Disorders

The present application claims the benefit of priority of U.S. Provisional Application No. 62/574,132, filed on October 18, 2017, U.S. Provisional Application No. 62/574,137, filed on October 18, 2017, and U.S. Provisional Application No. 62/574, 141 , filed on October 18, 2017; the contents of these applications are each incorporated herein by reference.

Neurodegenerative diseases are those that affect neurons, whereas Lysosomal storage disorders (LSDs) are a group of inherited metabolic diseases caused by defects in lysosomal homeostasis. In addition, ageing by itself can lead to problems with a person's ability to move around as well as some degree of decline in cognitive capacity, symptoms often including forgetfulness, decreased ability to maintain focus, decreased problem-solving capacity and/or reduced spatial awareness. Mobility problems may include unsteadiness while walking, difficulty getting in and out of a chair, or falls. Muscle weakness, joint problems, pain, disease and neurological (brain and nervous system) difficulties - common conditions in older people - can all contribute to mobility problems. Sometimes several mild problems occur at one time and combine to seriously affect mobility. If left unchecked, symptoms can progress into more serious conditions, such as dementia and depression, or even neurodegenerative disease, such as Alzheimer's disease.

For neurodegenerative diseases, the degenerative process can involve the progressive loss of neuronal structure, the progressive loss of neuronal function, or progressive neuron cell death. Such progressive neurodegeneration often results in physical disability and mental deterioration. Many neurodegenerative diseases are severely progressive and unremitting, and there are few, if any, curative treatments. Although the process of neurodegeneration is not fully understood, therapeutic agents that are shown to be broadly neuroprotective are thought to be applicable to neurodegenerative diseases generally. In addition, many neurodegenerative diseases are associated with lysosomal dysfunction. This includes both

neurodegenerative lysosomal storage disorders (LSDs) and many other

neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, where links to lysosomal defects have been suggested.

To date, for example, LSDs encompass over 70 diseases with a collective clinical frequency of 1 :5000 live births. These diseases can be classified into two main groups: primary storage disorders resulting from a direct deficiency in degradation pathways (typically lysosomal enzyme deficiency disorders), and secondary storage disorders which are caused by malfunctioning downstream lysosomal proteins or processes that impact the lysosome (e.g. , defects in trafficking pathways).

The pathology of LSDs affects many of the body's systems, but most commonly the nervous system. Progressive neurodegeneration resulting in physical disability and mental deterioration are common symptoms. Such disorders are generally severely progressive and unremitting. They tend to present in the first few years of life and the severe progression results in frequent hospitalization. If left untreated, patients often die in their mid-teens. Adult-onset patients have also been described. Current therapeutic approaches for LSDs are limited. There are few, if any, curative treatments and many of the therapeutic options merely improve quality of life. For example, some LSDs have been responsive to bone marrow

transplantation or enzyme replacement therapy. Additionally, some benefit has been reported in a clinical trial of substrate reduction therapy (SRT) using an inhibitor of glycosphingolipid (GSL) biosynthesis: the imino sugar drug, miglustat (Patterson, 2006). However, there are currently no general non-specific treatments that benefit all LSDs.

Moreover, many factors are believed to contribute to age-related cognitive decline, including oxidative stress and free radical damage, chronic low-level inflammation, declining hormone levels (like estrogen, testosterone, DHEA and pregnenolone), inner arterial lining (endothelium) dysfunction, insulin resistance, excess body weight, suboptimal nutrition, loneliness, lack of social network and high stress, amongst other things.

There remains a need for developing improved treatments for neurodegenerative diseases, LSDs, and for patients with signs and symptoms of ageing, such as impaired mobility and cognitive decline. For example, new therapies could benefit elderly people, by preventing or reducing symptoms such as impaired mobility and cognitive decline. Furthermore, although impaired mobility and/or cognitive function may be often associated with ageing, such signs may also be observed in any subject that presents with lower baseline levels of mobility and/or cognitive function. There remains a need for new therapies to prevent or reduce such symptoms in subjects suffering therefrom.

The present disclosure addresses a need to develop improved and widely

applicable treatments for neurodegenerative diseases, LSDs, and for preventing or reducing symptoms, such as impaired mobility and cognitive decline. For instance, the present disclosure describes leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof for use in a method of improving cognitive function, mobility, or cognitive function and mobility, and for treating a neurodegenerative disease or LSD, or one or more symptoms of a neurodegenerative disease or LSD in a subject. The neurodegenerative disease may, but need not, be associated with lysosomal dysfunction.

In one embodiment, there is disclosed leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof for use in a method of treating a neurodegenerative disease or LSD, or one or more symptoms associated with a neurodegenerative disease or LSD. In one embodiment, the neurodegenerative disease is not cerebellar ataxia or Niemann-Pick type C disease. In another embodiment, the LSD is not Niemann-Pick Type C. In one embodiment of the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, is disclosed for direct delivery in a subject in need thereof, for use in a method of treating a neurodegenerative disease or LSD, wherein the subject is asymptomatic. In another embodiment, there is disclosed leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof for use in a method of delaying onset of a neurodegenerative disease or LSD, or one or more symptoms of a

neurodegenerative disease or LSD that would otherwise be expected to manifest according to typical disease progression.

In a further embodiment, the present disclosure includes leucine, or a pharmaceutically acceptable salt thereof, for direct deliver in a subject in need thereof, for use in a method of treating a LSD or neurodegenerative disease, or one or more symptoms associated with a LSD or neurodegenerative disease, wherein the method comprises administering a therapeutically effective amount of the leucine or a pharmaceutically acceptable salt thereof to the subject in need thereof for a duration chosen from at least about 3 months, at least about 6 months, at least about 1 year, at least about 2 years, and at least about 5 years.

In one embodiment, the present disclosure describes leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof for use in a method of delaying progression of a LSD or neurodegenerative disease, or one or more symptoms associated with a LSD or neurodegenerative disease over time as compared to typical disease progression, wherein the method comprises administering a therapeutically effective amount of the leucine, or a pharmaceutically acceptable salt thereof for a duration chosen from at least about 3 months, at least about 6 months, at least about 1 year, at least about 2 years, and at least about 5 years.

In a further embodiment, leucine, or a pharmaceutically acceptable salt thereof, is disclosed for direct delivery in a subject in need thereof, for use in a method of reversing progression of a LSD or neurodegenerative disease, or one or more symptoms associated with a LSD or neurodegenerative disease over time, wherein the method comprises administering a therapeutically effective amount of the leucine, or a pharmaceutically acceptable salt thereof for a duration chosen from at least about 3 months, at least about 6 months, at least about 1 year, at least about 2 years, and at least about 5 years.

In another embodiment, leucine, or a pharmaceutically acceptable salt thereof, is disclosed for direct delivery in a subject in need thereof, for use in a method of improving in the subject a biochemical marker of a LSD or neurodegenerative disease over time, wherein the method comprises administering a therapeutically effective amount of the leucine, or a pharmaceutically acceptable salt thereof for a duration chosen from at least about 3 months, at least about 6 months, at least about 1 year, at least about 2 years, and at least about 5 years. In another embodiment, the present disclosure includes leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in the subject in need thereof, for use in a method of reducing the severity of a LSD or neurodegenerative disease or reducing the severity of or eliminating one or more existing symptoms associated with a LSD or neurodegenerative disease. In one embodiment, the neurodegenerative disease is not cerebellar ataxia or Niemann-Pick Type C. In one embodiment, the LSD is not Niemann- Pick Type C.

In a further embodiment, the present disclosure includes leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof, for use in a method of providing neuroprotection in the subject having, suspected of having, or at risk of having a LSD or neurodegenerative disease, wherein the method comprises administering a therapeutically effective amount of the leucine, or a pharmaceutically acceptable salt thereof for a duration chosen from at least about 3 months, at least about 6 months, at least about 1 year, at least about 2 years, and at least about 5 years. In one embodiment, the present disclosure includes leucine, or a pharmaceutically acceptable salt thereof, for direct delivery to the central nervous system in a method disclosed herein, wherein the direct delivery is by an administration chosen from intranasal administration, intraventricular administration, intrathecal administration, intracranial administration, and administration via nasal mucosal grafting. In one embodiment, leucine, or a pharmaceutically acceptable salt thereof, is disclosed for direct delivery to the central nervous system in a method disclosed herein, wherein the direct delivery is by intrathecal administration.

Additional embodiments of the present disclosure include, leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof, for use in a method of delaying progression of a neurodegenerative disease or a lysosomal storage disorder (LSD). In another embodiment, leucine, or a pharmaceutically acceptable salt thereof, for direct deliver y in a subject in need thereof, for use in a method of providing neuroprotection, wherein the subject has a neurodegenerative disease or a LSD. In an embodiment, the leucine is in racemate form, in an enantiomeric excess of the L- enantiomer or in an enantiomeric excess of the D-enantiomer. In another embodiment, the methods further comprise administering the leucine in a dose of between 1.5 g and 10 g per day. Further still, in an embodiment, the methods further comprise administering the leucine, or a pharmaceutically acceptable salt thereof for a treatment duration of two weeks or more. For example, the methods may also comprise administering the leucine, or a pharmaceutically acceptable salt thereof, before the onset of a symptom of the disease or disorder to be treated. Yet in an additional embodiment, the methods further comprise administering another therapy or agent intended to prevent or treat the disease or disorder to be treated. In one embodiment, the present disclosure provides for a kit for delaying progression of a neurodegenerative disease or a LSD in a subject, the kit comprising a means for diagnosing or prognosing a neurodegenerative disease or a LSD, and leucine, or a pharmaceutically acceptable salt thereof. For example, the kit comprises a means for diagnosing or prognosing a neurodegenerative disease or a LSD, and leucine, or a pharmaceutically acceptable salt thereof. In a further embodiment of the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, is used as a

neuroprotective agent in a subject having a neurodegenerative disease or a LSD. In a further embodiment of the methods, the kits, or the uses, the neurodegenerative disease is associated with defects in lysosomal storage. In an embodiment of the methods, the kits, or the uses, the neurodegenerative disease is alcoholism, Alexander's disease, Alper's disease, Alzheimer's Disease, amyotrophic lateral sclerosis (ALS), ataxia telangiectasia, neuronal ceroid lipofuscinoses, Batten disease, bovine spongiform encephalopathy (BSE), Canavan disease, cerebral palsy, Cockayne syndrome, corticobasal degeneration, Creutzfeldt-Jakob disease, frontotemporal lobar degeneration, Huntington's disease, HIV-associated dementia, Kennedy's disease, Lewy body dementia, neuroborreliosis, Machado-Joseph disease, multiple system atrophy, multiple sclerosis, multiple sulfatase deficiency, mucolipidoses, narcolepsy, Niemann Pick disease,

Parkinson's Disease, Pick's disease, Pompe disease, primary lateral sclerosis, prion diseases, progressive supranuclear palsy, Refsum's disease, Schilder's disease, subacute combined degeneration of spinal cord secondary to pernicious anaemia, Spiel meyer-Vogt- Sjogren- Batten disease, spinocerebellar ataxia, spinal muscular atrophy, Steele- Richardson-Olszewski disease, or Tabes dorsalis.

In a further embodiment of the methods, the kits, or the uses, the LSD is Niemann-Pick Type C (NPC1 and/or NPC2 defect), Smith-Lemli-Opitz Syndrome (SLOS), an inborn error of cholesterol synthesis, Tangier disease, Pelizaeus-Merzbacher disease, a neuronal ceroid lipofuscinosis, a primary glycosphingolipidosis, Farber disease or multiple sulphatase deficiency. Additionally, in another embodiment of the method, the kit, or the use, the primary glycosphingolipidosis is Gaucher disease, Fabry disease, GM1 gangliosidosis, GM2 gangliosidosis, Krabbe disease or metachromatic leukodystrophy (MLD). A further embodiment of the method, the kit, or the use, the LSD is NPC, Tay- Sachs disease, Sandhoff disease, GM1 gangliosidosis, Fabry disease, a

neurodegenerative mucopolysaccharidosis, MPS I, MPS IH, MPS IS, MPS II, MPS III, MPS IIIA, MPS NIB, MPS NIC, MPS HID, MPS, IV, MPS IV A, MPS IV B, MPS VI, MPS VII, MPS IX, a disease with secondary lysosomal involvement, SLOS, or Tangier disease. In an additional embodiment of the methods, the kits, or the uses, the neurodegenerative disease is cerebellar ataxia, Niemann Pick disease, parkinsonism, neuronopathic Gaucher disease, Sandhoff's disease, Louis-Barr syndrome, Alzheimer's disease, Parkinson's disease, multiple systems atrophy, fronto-temporal dementia or lower body Parkinson's syndrome. In still a further embodiment of the methods, the kits or the uses, the neurodegenerative disease is Niemann Pick disease, Niemann Pick type C, Niemann Pick type A, Tay-Sachs disease, Sandhoff's disease, amyotrophic lateral sclerosis (ALS), multisystemic atrophy cerebellar type (MSA-C), fronto-temporal dementia with

parkinsonism, corticobasal-degeneration-syndrome, progressive supranuclear palsy or cerebellar downbeat nystagmus. In an embodiment of the methods, the kits, or the uses, the LSD is Niemann Pick disease, Niemann Pick type C, Niemann Pick type A, Tay-Sachs disease, Sandhoff's disease or mucolipidosis type II.

In at least some embodiments, there is provided leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof, for use in a method of improving cognitive function. In another embodiment, there is provided leucine, or a pharmaceutically acceptable salt thereof, for use in a method of improving mobility in a subject. In a further embodiment, the subject is an elderly subject. Further, there is provided leucine, or a pharmaceutically acceptable salt thereof delivery directly to the subject in need thereof, for use in a method of improving mobility and/or cognitive function, wherein the subject is an elderly subject.

In another embodiment, there is provided a method of improving mobility and/or cognitive function in an elderly subject, the method comprising directly administering a

therapeutically effective amount of leucine, or a pharmaceutically acceptable salt thereof, to the subject. In one embodiment, the cognitive function is one or more selected from the group consisting of perception, memory, creation of imagery, awareness, reasoning, thinking and capacity for judgment. According to the present disclosure, leucine, or pharmaceutically acceptable salt thereof may be used to treat an age-related decrease in cognitive function and/or mobility.

In one embodiment, the leucine is used in a dose of between 0.5 g and 15 g, for example between 4 g and 10 g per day. In another embodiment, the leucine is used in a dose of more than 4 g to no more than 6 g per day. The dose of leucine may be administered, for example, across two or more

administrations. In one embodiment, the dose of leucine is administered across three administrations.

In one embodiment, the method comprises administering the leucine for a treatment duration of two weeks or more. In another embodiment, the method comprises administering the leucine for a treatment duration of seven weeks or more.

In one embodiment, the method comprises administering the leucine in a dose of between 1.5 g and 10 g, for example between 4.5 g and 10 g per day, taken across three administrations per day, for a treatment duration of two months or more.

In one embodiment, the subject is a well elderly subject. The subject may be otherwise healthy, except for an impairment of mobility and/or cognitive function where the mobility and/or cognitive function has reduced as the subject has aged i.e. reduced due to the aging process. In one embodiment, the subject does not have vertigo, and/or a neurological and/or neurodegenerative disease, disorder or condition. In one embodiment, the subject does not have vertigo.

In another aspect, the present disclosure provides use of leucine, or a pharmaceutically acceptable salt thereof, for improving cognitive function, mobility, or cognitive function and mobility in a subject.

In another aspect, the present disclosure provides a method of improving cognitive function, mobility, or cognitive function and mobility in a subject, the method comprising directly administering a therapeutically effective amount of leucine, or a pharmaceutically acceptable salt thereof, to the subject.

In another aspect, the present disclosure provides use of leucine, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for improving cognitive function, mobility, or cognitive function and mobility in a subject.

In another aspect, the present disclosure provides leucine, or a pharmaceutically acceptable salt thereof, for direct delivery to the central nervous system in a method disclosed herein, wherein the direct delivery is by an administration chosen from intranasal administration, intraventricular administration, intrathecal administration, intracranial administration, administration via nasal mucosal grafting, intravenous administration (e.g. IV injection) and oral administration (P.O). In another aspect, the present disclosure provides leucine, or a pharmaceutically acceptable salt thereof, for direct delivery to the central nervous system in a method disclosed herein, wherein the direct delivery is by intrathecal administration.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing summary, as well as the following detailed description of the disclosure, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, the attached drawings illustrate some, but not all, alternative embodiments. It should be understood, however, that the disclosure is not limited to the precise arrangements and instrumentalities shown. These figures, which are incorporated into and constitute part of the specification, assist in explaining the principles of the disclosure.

Figure 1 shows photographs of treated (Figure 1A) and untreated (Figure 1 B) A/pc7 ^{~ _} mice at nine weeks of age.

Figures 2A and 2B show weight data for A/pc7 ^{~ _} mice compared to wild-type (Npc1 ^+/+ ) mice, with and without acetyl-DL-leucine treatment from weaning.

Figures 3A - 3G show gait analysis data for A/pc7 ^~/_ mice compared to wild-type (A/pc7 ^+/+ ) mice, with and without acetyl-DL-leucine treatment from weaning. For example, diagonal support, cadence and step sequence data are shown in Figures 3A - 3C, respectively. Figures 3D and 3E show front paw (FP) data (stand mean and step cycle in panel D; duty cycle in panel E). Figures 3F and 3G show hind paw (HP) data (stand mean and step cycle in panel F; duty cycle in panel G).

Figures 4A - 4H show motor function analysis data for A/pc7 ^~/_ mice compared to wild-type (Npc1 ^+/+ ) mice, with and without acetyl-DL-leucine treatment from weaning. Centre rearing, activity, rearing and front to back (FR) count are shown in Figures 4A - 4D, respectively. Active time, mobile time, rearing time and total manual rearing count are shown in Figures 4E - 4H, respectively.

Figure 5 shows that treatment with acetyl-DL-leucine (0.1 g/kg from 3 weeks of age) is associated with a small but statistically significant increase in lifespan in the Npc1-/- mouse.

Figures 6A and 6B shows the reduction of lysosomal volume in non-neuronal NPC cells following treatment with acetyl-DL-leucine. Figures 6C-6H show the effect of treatment with acetyl-DL-Leucine on lysosomal volume in NPA, MLII , MPS NI B,

Aspartylglucosaminuria, MLI I IA, and MPS VI I patient fibroblasts, respectively.

Figure 7A shows a survival curve representing mortality in untreated or acetyl-leucine- treated wild-type and Sandhoff mice. Figure 7B shows bar crossing scores for untreated and acetyl-leucine-treated Sandhoff model mice. Figure 7C shows the step cycle time for untreated and acetyl-leucine-treated Sandhoff mice assessed at 12 weeks of age. Figures 8A-8C show the effect of treatment with acetyl-DL-leucine on glycosphingolipid (GSL) levels in GM2 gangliosidoses patient fibroblasts (Tay-Sachs disease, Sandhoff disease, and AB variant of Tay-Sachs disease, respectively).

Figure 9 shows a gait analysis matrix for a 75 year-old male patient diagnosed with corticobasal-degeneration-syndrome before and during treatment with acetyl-leucine, wherein fewer pink areas in the matrix indicate improvement compared to before treatment.

Figures 10A and 10B show the effect of treatment with acetyl-DL-leucine over time on the overall clinical severity score (CSS) and overall annual severity increment score (ASIS), respectively, of ten NPC patients.

Figures 11A-11J show the effect of treatment with acetyl-DL-leucine over time on the CSS subscores for each of the ten NPC patients.

Figures 12A and 12B show the effect of treating wild type NPC1 ^"A mice with acetyl-DL- leucine on levels of amyloid precursor protein C-terminal fragments (APP-CTFs) and levels of microtubule-associated protein 1 A/1 B-light chain 3-phosphatidylethanolamine conjugate (LC3-II), respectively.

Figures 13A-13C show that after treatment with acetyl-DL-leucine, a patient who had been diagnosed with downbeat nystagmus syndrome could partially suppress the nystagmus by visual fixation. Figure 14 shows the reduction of lysosomal volume in NPC Chinese Hamster Ovary

(CHO) cells following treatment with acetyl-DL-leucine, acetyl-D-leucine, acetyl-L-leucine, DL-leucine, D-leucine, and L-leucine, respectively.

Figure 15 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=13 (Baseline), 28 (Treatment) or 11 (washout) daily measurements, **** - p<0.0001. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods. Figure 16 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=1 1 (Baseline), 25 (Treatment) or 8 (washout) daily measurements, *- p<0.05. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods.

Figure 17 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=1 1 (Baseline), 18 (Treatment) or 5 (washout) daily measurements. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods.

Figure 18 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=6 (Baseline), 10 (Treatment) or 9 (washout) daily measurements. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods.

Figure 19 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=9 (Baseline), 20 (Treatment) or 3 (washout) daily measurements. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods. Figure 20 illustrates the Psychomotor Vigilance Task performance during baseline and treatment period. (A) Data is presented as mean ± SD of n=12 (Baseline), 23 (Treatment) or 9 (washout) daily measurements. Determination of statistical significance was performed via 1-way ANOVA with Tukey's correction. (B) Each individual data point is an average of the 10 trials that make up a daily test (mean ± SD, n=10). Dashed line indicates division between baseline/on-medication/washout periods. DESCRIPTION

Acetyl-leucine in racemate form (acetyl-DL-leucine) and salts of the same are effective in the treatment of vertigo of various origins, notably Meniere's vertigo and vertigo of inflammatory (vestibular neuritis) or toxic origin. For example, acetyl-leucine is marketed by Pierre Fabre Medicament in racemate form as an anti-vertigo medicament under the name Tanganil ^® . Clinical results of Tanganil ^® reported by various authors demonstrate an improvement in vertigo symptomology in more than 95% of cases, including the disappearance of vertigo attacks.

Acetyl-DL-leucine has been used in France to treat acute vertigo since 1957 and has an excellent safety profile, but its long-term safety in chronic use has not been determined. Despite numerous hypotheses, including stabilisation of membrane potential, its pharmacological and electrophysiological modes of action remain unclear. (Vibert N, Vidal PP. In vitro effects of acetyl-DL-leucine (tanganil) on central vestibular neurons and vestibulo-ocular networks of the guinea-pig. Eur J Neurosci 200 February; 13(4):735-48; Ferber-Viart C, Dubreuil C, Vidal PP. Effects of acetyl-DL-leucine in vestibular patients: a clinical study following neurotomy and labyrinthectomy. Audiol Neurootol 2009; 14(1): 17- 25). A FDG-μΡΕΤ study in a rat model of an acute unilateral labyrinthectomy (Zwergal A, Schlichtiger J, Xiong G, Beck R, Gunther L, Schniepp R et al. Sequential [F]FDG microPET whole-brain imaging of central vestibular compensation: a model of

deafferentation-induced brain plasticity. Brain Struct Fund 2016; 221 (1): 159-70) showed a significant effect of an L-enantiomer, N-acetyl-L-leucine, on postural compensation by activation of the vestibulo-cerebellum and a deactivation of the posterolateral thalamus ( Gunther L, Beck R, Xiong G, Potschka H, Jahn K, Bartenstein P et al. N-acetyl-L-leucine accelerates vestibular compensation after unilateral labyrinthectomy by action in the cerebellum and thalamus. PLoS One 2015; 10(3):e0120891). The symptomatic improvement of cerebellar ataxia using acetyl-DL-leucine was shown in a case series with cerebellar patients (Strupp M, Teufel J, Habs M, Feuerecker R, Muth C, van de

Warrenburg BP et al. Effects of acetyl-DL-leucine in patients with cerebellar ataxia: a case series. J Neurol 2013 October;260(10):2556-61). Another case series did not find benefit (Pelz JO, Fricke C, Saur D, Classen J. Failure to confirm benefit of acetyl-DL-leucine in degenerative cerebellar ataxia: a case series. J Neurol 2015 May;262(5): 1373-5). Quantitative gait analysis showed that acetyl-DL-leucine improved temporal gait variability in patients with cerebellar ataxia (Schniepp et al. (2015) Cerebellum; 3:8). In a one-month study involving 12 patients with Niemann-Pick Type C (NPC), symptomatic improvement of ataxia was shown (Bremova T, Malinova V, Amraoui Y, Mengel E, Reinke J, Kolnikova M et al. Acetyl-dl-leucine in Niemann-Pick type C: A case series. Neurology 2015 October 20;85(16):1368-75). Further, a PET study in patients with ataxia given acetyl-DL-leucine demonstrated an increased metabolism in the midbrain and lower brainstem in responders (Becker-Bense S, Feuerecker, R, Xiong G, Feil K, Bartenstein P, Strupp M, Dieterich M. FDG-PET in patients with cerebellar ataxia on- vs. off-treatment with Acetyl-DL-leucine. Abstract EAN 2015). Neither acetyl-leucine nor leucine is known to treat LSDs nor neurodegenerative diseases, which generally progress over the course of years to decades. The present disclosure surprisingly shows that leucine, or a pharmaceutically acceptable salt of the same, can be used in a method of treating a LSD or a

neurodegenerative disease in a subject in need thereof, for example, by delaying onset of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression, and/or by delaying or reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease, such as over long durations, as compared to typical disease progression.

Surprisingly, it has also been found, according to the present disclosure, that leucine, or a pharmaceutically acceptable salt of the same, improves mobility and cognitive function in the elderly.

These exemplary uses according to the present disclosure, as well as others described herein, were entirely unexpected, as such benefits had not been observed, and could not have been deduced, from the prior art teaching.

As evidenced by the Examples, which demonstrate effectiveness over a wide range of neurodegenerative diseases, the inventors believe that leucine is acting as a

neuroprotective agent and so inhibiting the neurodegeneration that would otherwise be expected to manifest. In addition, many neurodegenerative diseases are associated with defects in lysosomal storage, and, lysosomal dysfunction, such as aberrantly high levels of lysosomal storage, may be a cause of neuronal dysfunction and death. As evidenced by the Examples, but without wishing to be bound by any specific theory, the present inventors discovered, inter alia, that, leucine can improve cellular dysfunction (e.g., by reducing lysosomal volumes towards control values) and clinical abnormalities, and further provide neuroprotection. Surprisingly, the inventors show that leucine can also be used to benefit the elderly who, other than displaying the normal signs of ageing, may be in good health. Specifically, it has been found that leucine can improve mobility and cognitive function in the elderly. This was entirely unexpected, as such benefits had not been observed, and could not have been deduced, from the prior art teaching. The present disclosure shows that leucine can be used to treat subjects that have disorders distinct from ataxia (e.g. distinct from disorders such as cerebellar ataxia and Niemann Pick), and distinct from vertigo. For example, the subjects treated by the present disclosure may be otherwise healthy, except that they have an impairment of mobility where the mobility has been impaired due to the ageing process. The finding that leucine can be used to treat non-vertiginous disorders was surprising.

Consequently, the present disclosure provides leucine, or a pharmaceutically acceptable salt thereof, for direct delivery in a subject in need thereof, for use in a method of treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a

neurodegenerative disease. The present disclosure further provides leucine, or a pharmaceutically acceptable salt of the same, for direct delivery in a subject in need thereof, for use in a method of improving mobility and/or cognitive function, wherein the subject is an elderly subject.

"LSD", as used herein, refers to any disorder that involves dysfunction or disruption in the late endosomal/lysosomal system and the accumulation of undigested or partially digested macromolecules. The LSD may involve increased storage of lipids or non-lipids. LSDs are one of a heterogeneous group of inherited disorders often characterized by the accumulation of undigested or partially digested macromolecules resulting in cellular dysfunction (e.g., increased lysosomal volume compared to healthy subjects) and clinical abnormalities. A "subject", as used herein, may be a vertebrate, mammal or domestic animal. Hence, compositions according to the disclosure may be used to treat any mammal, for example livestock (e.g., a horse, cow, sheep or pig), pets (e.g., a cat, dog, rabbit or guinea pig), a laboratory animal (e.g., a mouse or rat), or may be used in other veterinary

applications. In one embodiment, the subject is a human being.

"Neurodegenerative disease", as used herein, refers to any disorder that affects neurons and involves the progressive loss of neuronal structure, the progressive loss of neuronal function, or progressive neuron cell death.

"Cognitive function" can mean any mental process that involves a symbolic operation, for example, perception, memory, creation of imagery, awareness, reasoning, thinking and capacity for judgment. Measures of cognitive functioning include assessment tools designed to measure, for example: (a) general intelligence, (b) nonverbal intelligence, (c) achievement, (d) attention/executive functioning, (e) memory and learning, (f) visual-motor and motor functioning and (g) language. Such assessment tools are well-known in the art and include, for example, Wechsler Adult Intelligence Scale and Woodcock-Johnson III Tests of Cognitive Abilities (both for assessing general intelligence), Raven Progressive Matrices (for assessing nonverbal intelligence), Wide Range Achievement Test and Woodcock-Johnson III Tests of Achievement (for assessing academic achievement), Conners' Continuous Performance Test II (for assessing attention/executive functioning), W\de Range Assessment of Memory and Learning (for assessing memory and learning), Bender Visual-Motor Gestalt Test, Halstead-Reitan Grip Strength Test, Halstead-Reitan Finger Tapping Test and Lafayette Grooved Pegboard Task (all for assessing visual-motor and motor functioning) and Peabody Picture Vocabulary Test (for assessing language). The phrase "improving cognitive function", as referred to herein, means a positive change in the ability of the subject to perform a symbolic operation, for example, to perceive, remember, create a mental image, have clarity of thought, be aware, to reason, think or judge. The term "decrease in cognitive function associated with ageing" as used herein refers to a decrease in cognitive function that is a direct consequence of the ageing process; in contrast with a decrease in cognitive function that is not a direct consequence of the ageing process. Clinical presentation may differ between subjects with a decrease in cognitive function associated with ageing and subjects with decrease in cognitive function that is not a direct consequence of the ageing process. The term "improving" may encompass treating and/or ameliorating any impaired mobility and/or cognitive decline in the subject. An age-related decrease in mobility and/or cognitive function may thus be partially or wholly reversed using leucine as described herein. "Mobility" refers to the ability of a subject to move. Mobility may be assessed in the elderly using one or more simple tests. As illustrated in the Examples, the "get up and go" test is a simple test capable of measuring mobility. In this test, the speed of sit to stand and walking to a target point is analysed, suitably as described in the Examples. For example, the test may begin with the subject sitting in a chair. At the start of the stop clock, the subject should rise unaided and walk to a target point. The target point may be 2-10 m away, optionally 4-6 m away. The stop clock should be stopped upon the subject reaching the target point. Any change in mobility, for example, over time or through treatment, can be monitored by using the "get up and go" test at two or more time points and comparing the results, again as illustrated in the Examples. Other suitable tests for measuring mobility include those used in the Elderly Mobility Scale (EMS), a 20-point validated assessment tool for the assessment of frail elderly subjects (Smith R. Validation and Reliability of the Elderly Mobility Scale. Physiotherapy 1994;80(1 1):744-7), considering locomotion, balance and key position changes. The phrase "improving mobility", as referred to herein, means a positive change in the ability of the subject to move. The positive change can be measured using any of the aforementioned tests on two or more occasions, for example, a first occasion to measure baseline mobility and a second occasion to measure mobility following a period of time (in which treatment may have been administered). The more confident the subject feels due to improved steadiness (with treatment, for example) the more rapidly s/he completes the test. Mobility could be said to be improved when at least a about 5% increase in performance in the relevant test, between two time points, is observed. For example, an increase in performance of at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or at least about 100% in the relevant test, between the two time points, is observed. Further for example, an increase in performance of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100% in the relevant test, between the two time points, is observed. The two time points may be one week apart, two weeks apart, three weeks apart, four weeks apart, two months apart, three months apart, four months apart, five months apart or even six months apart. Treatment may be administered during the intervening period. Thus, as an example, "improving mobility" can mean that the subject will demonstrate an at least about 5% increase in speed from a baseline measurement, as measured using the "get up and go" test as defined herein. For example, the subject may demonstrate an increase in speed in this test of at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or at least about 100%. Further for example, the subject may demonstrate an increase in speed in this test of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100%.

In one embodiment, the subject has a mobility disorder associated with ageing.

The term "mobility disorder associated with ageing" as used herein refers to an impairment in mobility that is a direct consequence of the ageing process; this is in contrast with an impairment in mobility that is not a direct consequence of the ageing process. Clinical presentation may differ between subjects with a mobility disorder associated with ageing and subjects with impairment in mobility that is not a direct consequence of the ageing process, for example subjects with ataxia. Ataxia may present as a subject slaloming during walking, while a mobility disorder associated with ageing may present as an increased propensity to falls. Thus, for example, cerebellar ataxia is not a mobility disorder associated with ageing. In addition to the mobility assessments disclosed above, mobility in a subject having a mobility disorder associated with ageing may be tested, for example, using assessments of balance and/or through monitoring the number of falls experienced by the subject. As used herein, the singular forms "a," "an," and "the" include plural reference.

The terms "approximately" and "about" mean to be nearly the same as a referenced number or value including an acceptable degree of error for the quantity measured given the nature or precision of the measurements.

As used herein, the terms "approximately" and "about" should be generally understood to encompass ± 20% of a specified amount, frequency or value. Numerical quantities given herein are approximate unless stated otherwise, meaning that term "about" or

"approximately" can be inferred when not expressly stated.

The terms "administer," "administration," or "administering" as used herein refer to (1) providing, giving, dosing and/or prescribing by either a health practitioner or his authorized agent or under his direction a composition according to the disclosure, and (2) putting into, taking or consuming by the patient or person himself or herself, a composition according to the disclosure.

References to "leucine" and "acetyl-leucine" throughout include pharmaceutically acceptable salts of the same, even if not expressly stated. The leucine or acetyl-leucine may be in racemic form, which means that the compound comprises about equal amounts of enantiomers. Alternatively, it may be present in an enantiomeric excess of either the L-enantiomer or the D-enantiomer. The leucine or acetyl-leucine may be in a single enantiomeric form of either the L-enantiomer or the D- enantiomer. In one embodiment, the single enantiomeric form is the L-enantiomer. The racemic and enantiomeric forms may be obtained in accordance with known procedures in the art.

A "pharmaceutically acceptable salt" as referred to herein, is any salt preparation that is appropriate for use in a pharmaceutical application. Pharmaceutically acceptable salts include, but are not limited to, amine salts, such as N,N'-dibenzylethylenediamine, chloroprocaine, choline, ammonia, diethanolamine and other hydroxyalkylamines, ethylenediamine, N-methylglucamine, procaine, N-benzylphenethylamine, 1-para-chloro- benzyl-2-pyrrolidin-T-ylmethylbenzimidazole, diethylamine and other alkylamines, piperazine, tris(hydroxymethyl)aminomethane and the like; alkali metal salts, such as lithium, potassium, sodium and the like; alkali earth metal salts, such as barium, calcium, magnesium and the like; transition metal salts, such as zinc, aluminum and the like; other metal salts, such as sodium hydrogen phosphate, disodium phosphate and the like;

mineral acids, such as hydrochlorides, sulfates and the like; and salts of organic acids, such as acetates, lactates, malates, tartrates, citrates, ascorbates, succinates, butyrates, valerates, fumarates and the like.

The leucine, or a pharmaceutically acceptable salt thereof of the same, may be formulated and administered to a subject in accordance with known teachings in the art. For example, the leucine, or a pharmaceutically acceptable salt thereof, may be formulated as a pharmaceutical composition. The pharmaceutical composition may comprise leucine, or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.

Reference to the pharmaceutical composition encompasses the active agent alone (e.g., leucine, or a pharmaceutically acceptable salt thereof) or in the form of a pharmaceutical composition.

The pharmaceutical composition may take any of a number of different forms depending, in particular, on the manner in which it is to be used. Thus, for example, it may be in the form of a powder, tablet, capsule, liquid, ointment, cream, gel, hydrogel, aerosol, spray, micellar solution, transdermal patch, liposome suspension or any other suitable form that may be administered to a person or animal in need of treatment.

A "pharmaceutically acceptable carrier" as referred to herein, is any known compound or combination of known compounds that are known to those skilled in the art to be useful in formulating pharmaceutical compositions. It will be appreciated that the carrier of the pharmaceutical composition should be one which is tolerated by the subject to whom it is given.

In one embodiment, the pharmaceutically acceptable carrier may be a solid, and the composition may be in the form of a powder or tablet. A solid pharmaceutically acceptable carrier may include, but is not limited to, one or more substances which may also act as flavouring agents, buffers, lubricants, stabilisers, solubilisers, suspending agents, wetting agents, emulsifiers, dyes, fillers, glidants, compression aids, inert binders, sweeteners, preservatives, dyes, coatings, or tablet-disintegrating agents. The carrier may also be an encapsulating material. In powders, the carrier may be a finely divided solid that is in admixture with the finely divided active agents according to the invention. In tablets, the active agent may be mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets may, for example, contain up to 99% of the active agents. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins. In another embodiment, the pharmaceutically acceptable carrier may be a gel and the composition may be in the form of a cream or the like.

The carrier may include, but is not limited to, one or more excipients or diluents. Examples of such excipients are gelatin, gum arabicum, lactose, microcrystalline cellulose, starch, sodium starch glycolate, calcium hydrogen phosphate, magnesium stearate, talcum, colloidal silicon dioxide, and the like.

In another embodiment, the pharmaceutically acceptable carrier may be a liquid. In one embodiment, the pharmaceutical composition is in the form of a solution. Liquid carriers are used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compositions. The leucine, or pharmaceutically acceptable salt thereof may be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fats. The liquid carrier may contain other suitable pharmaceutical additives such as solubilisers, emulsifiers, buffers, preservatives, sweeteners, flavouring agents, suspending agents, thickening agents, colours, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (partially containing additives as above, e.g. cellulose derivatives, such as sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration, the carrier may also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are useful in sterile liquid form compositions for parenteral administration. The liquid carrier for pressurised compositions may be a halogenated hydrocarbon or other pharmaceutically acceptable propellant.

Liquid pharmaceutical compositions, which are sterile solutions or suspensions, may be utilised by, for example, intramuscular, intrathecal, epidural, intraperitoneal, intravenous and subcutaneous injection. The active agent may be prepared as a sterile solid composition that may be dissolved or suspended at the time of administration using sterile water, saline, or other appropriate sterile injectable medium.

The compositions may be administered orally in the form of a sterile solution or suspension containing other solutes or suspending agents (for example, enough saline or glucose to make the solution isotonic), bile salts, acacia, gelatin, sorbitan monoleate, polysorbate 80 (oleate esters of sorbitol and its anhydrides copolymerized with ethylene oxide) and the like. The compositions may also be administered orally either in liquid or solid composition form. Compositions suitable for oral administration include solid forms, such as pills, capsules, granules, tablets, and powders, and liquid forms, such as solutions, syrups, elixirs, and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions, and suspensions.

Compositions may alternatively be administered by inhalation (e.g. intranasally).

Compositions may also be formulated for topical use. For instance, creams or ointments may be applied to the skin. Leucine, or a pharmaceutically acceptable salt thereof may be incorporated within a slow- or delayed-release device. Such devices may, for example, be inserted on or under the skin, and the medicament may be released over weeks or even months. Such devices may be advantageous when long-term treatment with leucine used according to the present disclosure is required and which may require frequent administration (e.g. at least daily administration).

In one embodiment, the pharmaceutical composition is a solid oral dosage form, such as a tablet. In tablets, the active agent may be mixed with a vehicle, such as a

pharmaceutically acceptable carrier, having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The tablets may contain up to 99% by weight of the active agents. Pharmaceutical compositions in solid oral dosage form, such as tablets, may be prepared by any method known in the art of pharmacy. Pharmaceutical compositions are usually prepared by mixing the active agent with conventional pharmaceutically acceptable carriers. A tablet may be formulated as is known in the art. Tanganil ^® , for example, includes wheat starch, pregelatinised maize (corn) starch, calcium carbonate and magnesium stearate as excipients. The same, or similar, excipients, for example, may be employed with the present disclosure.

The composition of each 700 mg Tanganil ^® tablet is as follows: 500 mg acetyl-DL-leucine, 88 mg wheat starch, 88 mg pregelatinised maize (corn) starch, 13 mg calcium carbonate and 11 mg magnesium stearate.

As discussed above, the leucine, or the pharmaceutically acceptable salt thereof may be formulated and administered as a pharmaceutical composition taking any number of different forms. For example, the leucine, or the pharmaceutically acceptable salt thereof may be formulated as a pharmaceutical composition to facilitate its delivery across the blood-brain barrier. As a further example, the leucine, or the pharmaceutically acceptable salt thereof may be formulated as a pharmaceutical composition for bypassing the blood- brain barrier. Formulations that facilitate delivery across the blood-brain barrier or that are suitable for administration in a manner that bypasses the blood-brain barrier may be used to prepare and administer leucine (not acetylated) as described herein. As demonstrated in the present disclosure, leucine exposure to cells exhibiting a lysosomal disease phenotype improved, like exposure to acetyl-leucine, the cellular dysfunction (e.g., by reducing lysosomal storage volumes towards control values), thereby demonstrating leucine's and acetyl-leucine's similar activity (see Figure 14). Such a delivery that crosses the blood-brain barrier or that is suitable for administration in a manner that bypasses the blood-brain barrier can be deemed "direct delivery" as used herein.

In one embodiment, the pharmaceutical composition (e.g., comprising leucine or salt thereof) is formulated for nanodelivery, e.g., colloidal drug-carrier systems. Suitable examples include but are not limited to liposomes, nanoparticles (e.g., polymeric, lipid and inorganic nanoparticles), nanogels, dendrimers, micelles, nanoemulsions, polymersomes, exosomes, and quantum dots. See, e.g., Patel et al., "Crossing the Blood-Brain Barrier: Recent Advances in Drug Delivery to the Brain," CNS Drugs 31 :109-133 (2017); Kabanov et al., "New Technologies for Drug Delivery across the Blood Brain Barrier," Curr Pharm Des., 10(12): 1355-1363 (2004); Cheng et al., "Highly Stabilized Curcumin Nanoparticles Tested in an In Vitro Blood-Brain Barrier Model and in Alzheimer's Disease Tg2576 Mice," The AAPS Journal, vol. 15, no. 2, pp. 324-336 (2013); Lahde et al. "Production of L-

Leucine Nanoparticles under Various Conditions Using an Aerosol Flow Reactor Method," Journal of Nanomaterials, vol. 2008, article ID 680897 (2008). For instance, as used herein, direct delivery may encompass formulations for nanodelivery.

In one embodiment, the pharmaceutical composition (e.g., comprising leucine or a salt thereof) is formulated for direct delivery to the central nervous system (CNS), such as by injection or infusion. Formulations for and methods of direct delivery to the CNS are known in the art. See, e.g., U.S. Patent No. 9,283, 181. Examples of such administration include but are not limited to intranasal, intraventricular, intrathecal, intracranial, administration via nasal mucosal grafting, intravenous administration (e.g. IV injection) and oral administration (P.O).

In one embodiment, the pharmaceutical composition is formulated for (and administered by) intranasal delivery. See, e.g., Hanson et al., "Intranasal delivery bypasses the blood- brain barrier to target therapeutic agents to the central nervous system and treat neurodegenerative disease," BMC Neurosci. 9(Suppl 3):S5 (2008). In one embodiment, the pharmaceutical composition is formulated for (and administered by) delivery via a nasal mucosal graft. In one embodiment, the pharmaceutical composition is formulated for (and administered by) intracerebroventricular injection or infusion. In another embodiment, the pharmaceutical composition is formulated for (and administered by) intrathecal intracisternal injection or infusion. In one embodiment, the pharmaceutical composition is formulated for (and administered by) intrathecal lumbar injection or infusion. For example, the active agent may be formulated for intrathecal administration and/or administered intrathecally in the same or a similar manner discussed by Ory et al., "Intrathecal 2-hydroxypropyl^-cyclodextrin decreases neurological disease progression in Niemann-Pick disease, type C1 : a non-randomised, open-label, phase 1-2 trial," Vol. 390, Issue 10104, pp. 1758-1768 (2017). Various techniques may be used including, without limitation, injection through a burrhole or cisternal or lumbar puncture or the like as known in the art. Various devices, whether internal (e.g., implanted) or external, may be used for delivery as known in the art, such as pumps, catheters, reservoirs, etc. In one embodiment, the administration interval is once every two weeks.

In yet a further embodiment, the pharmaceutical composition is formulated for (and administered by) intravenous injection or infusion. For example, leucine or a salt thereof may be formulated for intravenous administration using a needle or tube. In another embodiment, the pharmaceutical composition is formulated for (and administered by) oral administration. Intravenous and oral administrations are deemed to be encompassed by "direct deliver" as evidence suggests that leucine or a salt thereof can cross the blood- brain barrier.

In one embodiment, the administration interval is once every month. In one embodiment, the administration interval is once every two months. In one embodiment, the

administration interval is twice per month. In one embodiment, the administration interval is once every week. In one embodiment, the administration interval is twice or several times per week. In one embodiment, the administration interval is daily. In one

embodiment, the administration is continuous, such as continuous infusion.

Leucine, or a pharmaceutically acceptable salt thereof, may be administered in a dose or amount equivalent to those disclosed herein for acetyl-leucine, adjusted to account for either its direct delivery to the CNS or its delivery across the blood-brain barrier.

Similarly, leucine, or a pharmaceutically acceptable salt thereof may be administered in a dose or amount as disclosed herein; the dose may be adjusted according to its route of administration (e.g., direct delivery to the CNS).

In at least some embodiments, the present disclosure describes leucine and

pharmaceutically acceptable salts thereof, including compositions and methods thereof, for treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease in a subject in need thereof. The subject in need thereof may have a genetic, biochemical, or other similar identifiable marker of a LSD or a

neurodegenerative disease. For example, the marker of a LSD or a neurodegenerative disease may be a cellular marker. The subject in need thereof may have been diagnosed as having a LSD or a neurodegenerative disease. For example, the subject may have been diagnosed with a LSD or a neurodegenerative disease according to a genetic, biochemical, or other similar identifiable marker. The subject in need thereof may be suspected of having or at risk of having a LSD or a neurodegenerative disease. For example, the subject may have a genetic predisposition to a LSD or a neurodegenerative disease (e.g., the subject may have one or more family members with a LSD or a neurodegenerative disease). The subject in need thereof may be symptomatic (i.e., have one or more symptoms associated with a LSD or a neurodegenerative disease). The subject in need thereof may be asymptomatic. It should be understood that the terms "symptomatic" and "asymptomatic" are used with reference to symptoms of a LSD or a neurodegenerative disease. Subjects who have a genetic, biochemical, or other similar identifiable marker of a LSD or a neurodegenerative disease, such as subjects who have been diagnosed with a LSD or a neurodegenerative disease based on a genetic, biochemical, or other similar identifiable marker, but who have no further symptoms of the disease are included within the scope of "asymptomatic" for purposes of the present disclosure.

As used herein, "treating a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease" and the like refer to delaying onset of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression, reducing the severity of a LSD or a neurodegenerative disease, or reducing the severity of or eliminating one or more existing symptoms associated with a LSD or a neurodegenerative disease, delaying progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease over time as compared to typical disease progression, and/or reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease over time. "Treating a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease" may also refer to improving a biochemical marker of a LSD or a neurodegenerative disease.

As used herein, "typical disease progression," "disease progression that would typically be expected" and the like refer to the typical or expected progression of a LSD or a neurodegenerative disease, one or more symptoms associated with a neurodegenerative disease, or a biochemical marker of a LSD or a neurodegenerative disease if the subject were untreated. Typical or expected disease progression may be based, for example, on a known scale, index, rating, or score, or other suitable test, for assessing the progression of a LSD or a neurodegenerative disease, one or more symptoms of a neurodegenerative disease or associated with a LSD, or a biochemical marker of a LSD or a

neurodegenerative disease, such as those described as examples herein. The scale, index, rating, score, or other suitable test may correspond to the progression of the LSD or the neurodegenerative disease overall or to the progression of one or more symptoms associated with the LSD or the neurodegenerative disease. For instance, typical or expected disease progression may be based on the typical or expected onset or severity of the LSD or the neurodegenerative disease, or a symptom or collection of symptoms associated with the LSD or the neurodegenerative disease. The typical or expected disease progression may be determined on a subject-by-subject basis or may be based on what is typically observed for or experienced by a collection of subjects afflicted with the LSD or the neurodegenerative disease, such as a population or subpopulation of subjects. Subpopulations may include, for example, subpopulations of the same gender, of the same or similar age, of the same or similar timing for the onset of one or more symptoms, etc. In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to delaying onset of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression. As used herein, "delaying onset of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease" and the like refer to increasing the time to, or preventing, onset of the LSD or the neurodegenerative disease or one or more symptoms of the LSD or the neurodegenerative disease. For example, onset can be said to be delayed when the time to manifestation of a LSD or a

neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease takes at least 5% longer than that observed according to typical disease progression. Further, for example, an increase in time of at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100% is observed. In one embodiment, the subject is asymptomatic. The administration of leucine may be initiated at the time the subject is asymptomatic to delay onset of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression. In another embodiment, the subject is symptomatic. The administration of leucine may be initiated at the time the subject has some symptoms in order to delay onset of one or more additional symptoms of a LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression. The subject in need thereof may continue to receive treatment with leucine in accordance with the durations described herein. In one embodiment, the treatment prevents onset of one or more symptoms of the LSD or a neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression.

In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to reducing the severity of a LSD or a neurodegenerative disease, or reducing the severity of or eliminating one or more existing symptoms associated with a LSD or a neurodegenerative disease. The severity of a LSD or a neurodegenerative disease, or of the existing symptom(s), may be assessed using a known scale, index, rating, or score, such as those described as examples herein, or another suitable test for assessing severity. For example, the scale, index, rating, score, or other suitable test may correspond to the severity of the LSD or the neurodegenerative disease overall or to the severity of one or more symptoms associated with the LSD or the neurodegenerative disease. In one embodiment, the treatment improves such an assessment from a value or degree characteristic of a symptomatic patient to a value or degree characteristic of a non-symptomatic patient.

In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to delaying progression of a LSD or a neurodegenerative disease, or one or more symptoms associated with a LSD or a neurodegenerative disease over time as compared to typical disease progression, or reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms associated with a LSD or a neurodegenerative disease over time. The time over which the treatment delays or reverses progression may coincide with the duration of treatment as described herein. The treatment may delay or reverse progression over a duration of, for example, about seven days or more, about two weeks or more, about three weeks or more, about one month or more, about six weeks or more, about seven weeks or more or about two months or more. For example, the treatment may delay or reverse progression over a duration of about three months or more, about four months or more, about five months or more or about six months or more. It may delay or reverse progression over a duration of, for example, about 1 year or more, about 2 years or more, about 3 years or more, about 4 years or more, about 5 years or more, or about 10 years or more. The treatment may delay or reverse progression of the LSD or the neurodegenerative disease, or one or more symptoms associated with the LSD or the neurodegenerative disease over the lifetime of the patient.

In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to delaying progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a

neurodegenerative disease over time as compared to typical disease progression. As used herein, "delaying progression of a LSD or a neurodegenerative disease or one or more symptoms associated with a LSD or a neurodegenerative disease over time" and the like refer to slowing and/or stopping progression of the LSD or the neurodegenerative disease or one or more symptoms of the LSD or the neurodegenerative disease (e.g., slowing and/or stopping the worsening or increasing severity of the LSD or the

neurodegenerative disease or one or more symptoms of the LSD or the neurodegenerative disease) over time. Disease progression may be determined, for example, using a known scale, index, rating, or score, such as those described as examples herein, or another suitable test for assessing progression. For example, the scale, index, rating, score, or other suitable test may correspond to the progression of the LSD or the neurodegenerative disease overall or to the progression of one or more symptoms associated with the LSD or the neurodegenerative disease. In one embodiment, "delaying progression of a LSD or a neurodegenerative disease, or one or more symptoms associated with a LSD or a neurodegenerative disease" means that a subject's disease severity value (e.g., overall severity or severity of one or more symptoms) determined by a known scale, index, rating, score, etc., or other suitable test for evaluating severity, does not meaningfully increase (e.g., at least remains substantially constant). In one embodiment, "delaying progression of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease" means preventing the subject from reaching, or increasing the time taken for a subject to reach (e.g., decreasing the rate of change of increasing severity), a severity value according to a known scale, index, rating, score, etc., or other suitable test, for assessing progression compared to a value corresponding to typical disease progression. For example, progression can be said to be delayed when the time to reach a severity value takes at least 5% longer than that observed according to typical disease progression. Further for example, an increase in time of at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100% is observed. The time over which the treatment delays progression of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease may coincide with the duration of treatment as described herein. In one embodiment, the treatment delays progression for at least about three months, at least about four months, at least about five months, or at least about six months. The treatment may delay progression for at least about 1 year, at least about 2 years, at least about 3 years, at least about 4 years, at least about 5 years, or at least about 10 years. The treatment may delay progression over the lifetime of the patient.

In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to reversing progression of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a

neurodegenerative disease over time. As used herein, "reversing progression of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease over time" and the like refer to stopping progression and reducing the severity of the LSD or the neurodegenerative disease, or one or more symptoms of the LSD or the neurodegenerative disease over time. Disease progression and severity may be determined, for example, using a known scale, index, rating, or score, such as those described as examples herein, or another suitable test for assessing progression and severity. For example, the scale, index, rating, score, or other suitable test may correspond to the progression and severity of the LSD or the neurodegenerative disease overall or to the progression and severity of one or more symptoms associated with the LSD or the neurodegenerative disease. In one embodiment, "reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a

neurodegenerative disease over time" means that a subject's disease severity value (e.g., overall severity or severity of one or more symptoms) determined by a known scale, index, rating, score, etc., or another suitable test, for evaluating severity, improves over time (i.e., shows a reduction in severity over time). The time over which the treatment reverses progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease may coincide with the duration of treatment as described herein. In one embodiment, the treatment reverses progression for at least about three months, at least about four months, at least about five months, or at least about six months. In a further embodiment, the treatment reverses progression for at least about 1 year, at least about 2 years, at least about 3 years, at least about 4 years, at least about 5 years, or at least about 10 years. The treatment may reverse progression over the lifetime of the patient.

In one embodiment, "treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" refers to improving in the subject a biochemical marker of a LSD or a neurodegenerative disease (e.g., increased levels of the storage metabolite(s) or secondary biochemical changes resulting from the primary storage). A biochemical marker is a signal of disease activity and may provide ongoing indications of disease severity and progression over time. In one embodiment, the biochemical marker is improved in view of a control value. In one embodiment, the biochemical marker is chosen from increased lysosomal volume, increased

glycosphingolipid (GSL) levels, increased microtubule-associated protein 1 A/1 B-light chain 3-phosphatidylethanolamine conjugate (LC3-II) levels, and increased amyloid precursor protein C-terminal fragment (APP-CTF) levels. In one embodiment, the biochemical marker is increased lysosomal volume and the treatment reduces lysosomal volume in the subject. In one embodiment, the biochemical marker is increased glycosphingolipid (GSL) levels and the treatment reduces GSL levels in the subject. In one embodiment, the biochemical marker is increased microtubule-associated protein 1 A/1 B-light chain 3- phosphatidylethanolamine conjugate (LC3-II) levels and the treatment reduces LC3-II levels in the subject. In one embodiment, the biochemical marker is increased amyloid precursor protein C-terminal fragment (APP-CTF) levels and the treatment reduces APP- CTF levels in the subject. In one embodiment, the treatment improves a biochemical marker over time. For example, in one embodiment, improving a biochemical marker over time means that the treatment improves a biochemical marker over time toward a control value, prevents the progression of a biochemical marker over time, and/or delays the progression of the biochemical marker over time as compared to typical disease progression. The time over which the treatment improves a biochemical marker may coincide with the duration of treatment as described herein. In one embodiment, the treatment improves a biochemical marker for at least about three months, at least about four months, at least about five months, or at least about six months. The treatment may improve a biochemical marker for at least about 1 year, at least about 2 years, at least about 3 years, at least about 4 years, at least about 5 years, or at least about 10 years. The treatment may improve the biochemical marker over the lifetime of the patient.

A "symptom" of a LSD or a neurodegenerative disease includes any clinical or laboratory manifestation associated with a LSD or a neurodegenerative disease and is not limited to what the subject can feel or observe. Symptoms as described herein include, but are not limited to, neurological symptoms and psychiatric symptoms. Examples of neurological symptoms include ataxia, other movement disorders such as hypokinesia, rigor, tremor or dystonia, central ocular motor disorders such as vertical and horizontal supranuclear saccade/gaze palsy and neuropsychological deficits such as dementia. Examples of psychiatric symptoms include depression, behavioural disorders or psychosis. Onset of symptoms may range from birth to adulthood.

Progression of a neurodegenerative disease or a LSD or one or more symptoms of a LSD over time or through treatment can be monitored, for example, using one or more known tests at two or more time points and comparing the results. Disease progression and/or severity can be assessed, for example, using the Scale for the Assessment and Rating of Ataxia (SARA), Spinocerebellar Ataxia Functional Index (SCAFI), the International Cooperative Ataxia Rating Scale (ICARS), the brief ataxia rating scale (BARS), the modified Disability Rating Scale (mDRS), EuroQol 5Q-5D-5L (EQ-5D-5L), the visual analogue scale (VAS), neuropsychological tests, such as Wechsler Adult Intelligence Scale-Revised (WAIS-R), Wechsler Intelligence Scale for Children-IV (WISC-IV), Montreal Cognitive Assessment (MoCA), as well as scales used in movement disorders, such as the Unified Parkinson's Rating Scale (UPRS) or the Unified Multiple System Atrophy Rating Scale (UMSARS), or other suitable tests. For certain LSDs, such as NPC, particular scores have been developed and validated over the last decades, for instance the clinical severity score (CSS) and annual severity increment score (ASIS) (see Yanjanin et al., "Linear Clinical Progression, Independent of Age of Onset, in Niemann-Pick Disease, Type C," Am J Med Genet Part B 153B: 132-140) and the modified 6-Domain NP-C disability Scale (mDRS score). For example, an NPC patient's severity can be quantified by assigning a CSS, which assesses various parameters of the disease (ambulation, seizures, eye movement, etc.) and gives each parameter a score out of 5. A higher score equals a greater severity. The ASIS quantifies the annual rate of change in the CSS, calculated by dividing the CSS by the patient's age. In this regard, certain scores in these tests are characteristic of symptomatic LSD or neurodegenerative disease patients and evidence disease progression and/or severity.

Thus, "treating a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease", for example, may be equated to achieving an improved assessment, such as those described herein, of a SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-5L, VAS, WAIS-R, WISC-IV, CSS, UPRS, UMSARS, and/or MoCA score, or result of another test suitable for characterising a LSD subject or a neurodegenerative disease patient. For example, in one embodiment, "reducing the severity of a LSD or

neurodegenerative disease, or reducing the severity of or eliminating one or more existing symptoms of a LSD or a neurodegenerative disease" means improving a SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-5L, VAS, WAIS-R, WISC-IV, CSS, UPRS.UMSARS, and/or MoCA score, or a result of another suitable test, for evaluating severity, such as improving the score or result from a severity value characteristic of a symptomatic subject to a value characteristic of a non-symptomatic subject. In another embodiment, "delaying

progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease" means that a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-5L, VAS, WAIS-R, WISC-IV, CSS, UPRS, UMSARS, and/or MoCA score, or a result of another suitable test for evaluating progression, does not meaningfully increase (e.g., at least remains substantially constant). In a further embodiment, "delaying progression of a LSD or a neurodegenerative disease or one or more symptoms associated with a LSD or a neurodegenerative disease" means preventing a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D-5L, VAS, WAIS-R, WISC-IV, CSS, UPRS, UMSARS, and/or MoCA score, or a result of another suitable test for evaluating progression, from reaching, or increasing the time taken to reach, a value compared to that of typical disease progression. In another embodiment, "reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease over time" means that a subject's SARA, SCAFI, ICARS, BARS, mDRS, EQ-5D- 5L, VAS, WAIS-R, WISC-IV, CSS and/or MoCA score, or a result of another suitable test for evaluating progression, improves over time (i.e., shows a reduction in severity over time).

For example, to evaluate overall neurological status, mDRS, a four-domain scale

(ambulation, manipulation, language and swallowing), may be applied. Cerebellar function may be evaluated using SARA, an eight-item clinical rating scale (gait, stance, sitting, speech, fine motor function and taxis; range 0-40, where 0 is the best neurological status and 40 the worst), and SCAFI, comprising the 8-m-Walking-Time (8MW; performed by having patients walking twice as quickly as possible from one line to another excluding turning), 9-Hole-Peg-Test (9HPT) and the number of "PATA" repetitions over 10 s.

Subjective impairment and quality of life may be evaluated using the EQ-5D-5L

questionnaire and VAS. To assess ocular motor function, 3-dimensional videooculography (EyeSeeCam) may be used to measure the peak velocity of saccades, gain of smooth pursuit, peak slow phase velocity of gaze-evoked nystagmus (gaze-holding function), peak slow phase velocity of optokinetic nystagmus, and gain of horizontal vestibulo-ocular reflex. To evaluate the cognitive state, WAIS-R or WISC-IV, and MoCA, assessing different cognitive domains, including attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation with a maximum of 30 points and a cut-off score of 26, may be used. The skilled person will know how to perform these and other such tests. In one embodiment, leucine, or a pharmaceutically acceptable salt of the same, may be administered, for example, at a dose ranging from about 500 mg to about 15 g per day or ranging from about 500 mg to about 10 g per day, such as ranging from about 1.5 g to about 10 g per day, optionally by solid oral or liquid oral route. The leucine, or a pharmaceutically acceptable salt of the same, may be administered, for example, in a dose according to that of Tanganil ^® , which is prescribed to adults in a dose of 1.5 g to 2 g per day, 3-4 tablets in two doses, morning and evening. In another embodiment, leucine, or a pharmaceutically acceptable salt of the same, is administered in a liquid pharmaceutical composition, which is a sterile solution or suspension. For example, leucine, or a pharmaceutically acceptable salt of the same, may be administered to a subject by intrathecal or intravenous injection. Leucine may be prepared as a sterile solid composition that may be dissolved or suspended at the time of administration using sterile water, saline, or other appropriate sterile injectable medium, in at least some embodiments, leucine, or a pharmaceutically acceptable salt of the same, is administered by intrathecal or intravenous injection at a dose ranging from about 1 mg/mL to about 24 mg/mL. It may be from about 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 16, 17, 18, 19, 20, 21 , 22 mg/mL to about 23 mg/mL. It may be from about 18, 19, 20 mg/mL to about 21 mg/mL.

In another embodiment, leucine, or a pharmaceutically acceptable salt of the same, may be administered daily at a dose of about 3 mg/kg to about 113 mg/kg. It may be from about 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 , 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 , 52, 53, 54, 55, 56, 57, 58, 59, 60, 61 , 62, 63, 64, 65, 66, 67, 68, 69, 70, 71 , 72, 73, 74, 75, 76, 77, 78, 79, 80, 81 , 82, 83, 84, 85, 86, 87, 88, 89, 90, 91 , 92, 93, 94, 95, 96, 97, 98, 99, 100, 101 , 102, 103, 104, 105, 106, 107, 108, 109, 1 10, 1 11 mg/kg to about 112 mg/kg. In one embodiment, despite interspecies differences in metabolism, a daily administration of 60 mg/kg leucine, or a pharmaceutically acceptable salt of the same, in a rat is equal to about 8 g of leucine in patients.

If one enantiomer is administered, the doses may be reduced accordingly. For instance, if only L-leucine or if only D-leucine is administered, the dose may range from about 250 mg to about 15 g per day, range from about 250 mg to about 10 g per day, or range from about 250 mg to about 5 g per day, such as from about 0.75 g to about 5 g per day.

In one embodiment, the administered dose ranges from about 0.5 g to about 15 g per day, from about 0.5 g to about 13 g per day from about 1 g to about 10 g per day, or from about 1.5 g to about 7 g per day. It may be from about 0.5, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, or 14 g to about 15 g per day. It may be from about 2, 3, 4, 5, 6, 7, 8 or 9 g to about 10 g per day. It may be more than about 1.5 g per day, but less than about 15, 14, 13, 12, 11 , 10, 9, 8, 7, 6 or 5 g per day. In one embodiment, the dose ranges from about 4 g to about 6 g per day. In one embodiment, the dose ranges from about 4 g to about 5 g per day. In one embodiment, the dose is about 0.5, 1 , 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11 , 1 1.5, 12, 12.5, 13, 13.5, 14, 14.5, or 15 g per day. In one embodiment, the dose is about 4.5 g per day. In one embodiment, the dose is about 5 g per day. In one embodiment, these doses are administered in a solid oral dosage form, notably tablets. In another embodiment, these doses are for leucine when in its racemic form. Doses for leucine when an enantiomeric excess is present may be lower than those recited here, for example, around 50% lower. The above recited dose-ranges when halved are thus also explicitly encompassed by the present disclosure. In one embodiment, the total daily dose may be spread across multiple administrations, i.e. administration may occur two or more times a day to achieve the total daily dose. As an example, the required number of tablets to provide the total daily dose of leucine may be split across two administrations (for example, in the morning and evening) or three administrations (for example, in the morning, noon and evening). Each dose may be suitably administered with or without food. For example, leucine may be dosed by about 1 or about 2 hours before meals, such as at least about 20 minutes, at least about 30 minutes, at least about 40 minutes, or at least about 1 hour before meals, or may be dosed by about 1 , about 2, or about 3 hours after meals, such as waiting at least about 20 minutes, at least about 30 minutes, at least about 1 hour, at least about 1.5 hours, at least about 2 hours, or at least about 2.5 hours after meals. For example, a total daily dose of 4.5 g leucine may be administered as three Tanganil ^® (or equivalent) tablets before, with, or after breakfast, three further tablets before, with, or after lunch and three further tablets before, with, or after dinner.

Administration of leucine in accordance with the present disclosure may be initiated before or after a subject is found to have a genetic, biochemical, or other similar identifiable marker of a LSD or a neurodegenerative disease, such as, in the case of the former, when the subject is suspected of having or is at risk of having a LSD or a neurodegenerative disease. Administration may be initiated at or around the time a subject is found to have a genetic, biochemical, or other similar identifiable marker of a LSD or a neurodegenerative disease. Similarly, administration may be initiated before, at or around the time, or after a subject is diagnosed with a LSD or a neurodegenerative disease, such as before, at or around the time, or after a subject is found to have a genetic, biochemical, or other similar identifiable marker of a LSD or a neurodegenerative disease. Administration of leucine may be initiated when the subject is symptomatic or asymptomatic. In particular, one of the advantages of treatment with leucine, according to the present disclosure, is that the administration may be initiated as early as the time after a subject is found to have a genetic and/or biochemical marker of a LSD or a neurodegenerative disease but before the subject shows symptoms of the LSD or a neurodegenerative disease (other than the genetic and/or biochemical marker, i.e., the subject is asymptomatic) or before the subject shows one or more symptoms considered hallmarks of the disease. The treatment may delay onset of the LSD or a neurodegenerative disease or one or more symptoms associated with the LSD or a neurodegenerative disease, as described herein. The treatment may also be continued for a duration as described herein.

As discussed herein, an advantage of treatment with leucine, according to the present disclosure, is that it may be administered over a long duration of time to, for example, delay or even reverse progression of a LSD or a neurodegenerative disease or one or more symptoms of a LSD or a neurodegenerative disease in a subject as compared to typical disease progression. Treatment duration may be, for example, about seven days or more, about two weeks or more, about three weeks or more, about one month or more, about six weeks or more, about seven weeks or more, or about two months or more. In one embodiment, it is about three months or more, about four months or more, about five months or more or about six months or more. The treatment duration may be about 1 year or more, about 2 years or more, about 4 years or more, about 5 years or more, or about 10 years or more. The treatment duration may be the life-time of the patient.

Any and all combinations of dosage form, dose amount, dosing schedule and treatment duration are envisaged and encompassed by the invention. In one embodiment, the dose is from about 4 g to about 10 g per day, taken across one, two, or three administrations per day, for a treatment duration of about two months or more. In another embodiment, the dose is more than 4 g but no more than 5 g per day, taken across one, two, or three administrations per day, for a treatment duration of about six months or more. The dosage form may be a solid oral dosage form, notably tablets. The pharmaceutical compositions described herein may be used as a monotherapy (e.g., use of the active agent alone) for treating a LSD or a neurodegenerative disease in a subject. Alternatively, the pharmaceutical compositions may be used as an adjunct to, or in combination with, other known therapies, e.g., for treating a LSD or a neurodegenerative disease in a subject.

All LSDs, which may be classified in various ways, are within the scope of the present disclosure. In one embodiment, the LSD is chosen from any of glycogen storage disease, mucopolysaccaridoses, mucolipidoses, oligosaccharidoses, lipidoses, sphingolipidoses, and lysosomal transport diseases.

The sphingolipidoses may be chosen from any of Niemann-Pick disease type A/B, Gaucher disease types 1, 11, and III, Krabbe disease, Fabry disease, Schindler Disease, GM1 gangliosidosis, Morquio B disease, GM2 gangliosidoses, metachromatic

leukodystrophy, Farber disease, multiple sulfatase deficiency, lysosomal acid lipase deficiency and galactosialidosis. In one embodiment, the sphingolipidoses are chosen from Niemann-Pick disease type A, GM1 gangliosidosis, Tay-Sachs disease, the AB variant of Tay-Sachs disease, and Sandhoff disease.

The mucolipidoses may be chosen from any of mucolipidosis I, mucolipidosis II, mucolipidosis III, and mucolipidosis IV. In one embodiment the mucolipidosis is mucolipidosis II or mucolipidosis III.

The mucopolysaccharidoses may be chosen from any of MPS IH, MPS I H-S, MPS IS, MPS IIA, MPS MB, MPS IIIA-D, MPS IVA, MPS VI, MPS VII and MPS IX. In one embodiment, the mucopolysaccharidosis is MPS III or MPS VII. In one embodiment, the mucopolysaccharidosis is MPS 1MB.

The oligosaccharidoses may be chosen from any of beta-mannosidosis, alpha-fucosidosis, and aspartylglucosaminuria. In one embodiment, the oligosaccharidosis is

aspartylglucosaminuria.

The lipidoses may be chosen from any of Niemann-Pick disease type C, Niemann-Pick disease type D, neuronal ceroid lipofuscinoses (Type I to X inclusive), and Wolman disease. In one embodiment, the lipidosis is Niemann-Pick disease type C.

The glycogen storage disease may be chosen from Infantile-onset Pompe disease, Late- onset Pompe disease and Danon disease. The lysosomal transport diseases may be chosen from cystinosis, pycnodysostosis, sialic acid storage disease and infantile free sialic acid storage disease. The LSD may be a primary lysosomal hydrolase defect, a post-translational processing defect of lysosomal enzymes, a trafficking defect for lysosomal enzymes, a defect in lysosomal enzyme protection, a defect in soluble non-enzymatic lysosomal proteins, a transmembrane (non-enzyme) protein defect or an unclassified defect. In one embodiment, the LSD is chosen from a primary lysosomal hydrolase defect.

Primary lysosomal hydrolase defects include, but are not limited to, Tay-Sachs disease (β- hexosaminidase A defect), Sandhoff disease (β-hexosaminidase A+B defect), Fabry disease (a-galactosidase A defect), Krabbe disease (β-galactosyl ceramidase defect), Niemann-Pick Type A and B (sphingomyelinase defect), metachromatic leukodystrophy (arylsulphatase A defect), MPS IH (Hurler syndrome; a-iduronidase defect), MPS IS (Scheie syndrome; a-iduronidase defect), MPS IH-S (Hurler-Scheie syndrome; a- iduronidase defect), MPS II (Hunter syndrome; iduronate sulphatase defect), MPS IIIA (Sanfilippo A syndrome; heparan sulphamidase defect), MPS 1MB (Sanfilippo B syndrome; acetyl a-glucosaminidase defect), MPS NIC (Sanfilippo C syndrome; acetyl CoA: a- glucosaminide N-acetyltransferase defect), MPS MID (Sanfilippo D syndrome; N-acetyl glucosamine-6-sulphatase defect), MPS IV A (Morquio A disease; acetyl galactosamine-6- sulphatase defect), MPS IVB (Morquio B disease; β-galactosidase defect), MPS V

(redesignated MPS IS), MPS VI (Maroteaux Lamy Syndrome; acetyl galactosamine-4- sulphatase (arylsulphatase B) defect), MPS VII (Sly Syndrome; β-glucuronidase defect), MPS IX (hyaluronidase defect), Wolman/cholesteryl ester storage disease (WD; acid lipase defect), Pompe disease (Type II; a 1 ,4-glucosidase defect), aspartylglucosaminuna (glycosylasparaginase defect), fucosidosis (a-fucosidase defect), a-mannosidosis (a- mannosidase defect), β-mannosidosis (β-mannosidase defect), Schindler disease (N- acetylgalactosaminidase defect), sialidosis/ML I (a-neuraminidase defect), infantile neuronal ceroid lipofuscinosis (CLN1 ; palmitoyl protein thioesterase defect), late infantile neuronal ceroid lipofuscinosis (CLN2; carboxypeptidase defect), early infantile GM1 gangliosidosis, late infantile GM1 gangliosidosis, adult infantile GM1 gangliosidosis, Gaucher Disease Type 1 (Non-Neuronopathic), Gaucher Disease Type 2/3 (Neuronopathic), Neuronal Ceroid Lipofuscinosis Type 4 (CLN4; Kufs disease; Adult NCL; palmotoyl-protein thioesterase-1 deficiency (Type A); Cathepsin F deficiency (Type B)), Neuronal Ceroid Lipofuscinosis Type 10 (CLN10; Congenital Cathepsin D Deficiency), Pycnodysostosis (Cathepsin K defect), Infantile-Onset Pompe Disease, Late-Onset Pompe Disease, Farber Disease (Farber's lipogranulomatosis; ceramidase deficiency; Fibrocytic dysmucopolysaccharidosis; Lipogranulomatosis) and Galactosialidosis (protective protein cathepsin A defect, PPCA defect). In one embodiment, the primary lysosomal hydrolase defect is chosen from Tay-Sachs disease, Sandhoff disease, Niemann-Pick Type A, Niemann-Pick Type B, neuronal ceroid lipofuscinoses, Gaucher disease, Fabry disease, Krabbe disease, GM1 gangliosidosis, GM2 gangliosidosis, metachromatic leukodystrophy, and Farber disease. In one embodiment, the primary lysosomal hydrolase defect is chosen from Tay-Sachs disease, Sandhoff disease, Niemann-Pick Type A, Niemann-Pick Type B, and GM1 gangliosidosis.

In one embodiment, the LSD is chosen from a post-translational processing defect of lysosomal enzymes. Post-translational processing defects of lysosomal enzymes include, but are not limited to, mucosulphatidosis (MSD; multiple sulphatase defect), MLII (l-cell disease; N-acetyl glucosamine phosphoryl transferase defect) and MLIII (pseudo-Hurler polydystrophy; N-acetyl glucosamine phosphoryl transferase defect). In one embodiment, the LSD is chosen from a trafficking defect for lysosomal enzymes. Trafficking defects for lysosomal enzymes include, but are not limited to, mucolipidosis type II (l-cell disease; N-acetyl glucosamine phosphoryl transferase defect), mucolipidosis type IDA (pseudo-Hurler polydystrophy; N-acetyl glucosamine phosphoryl transferase defect) and mucolipidosis type INC.

In one embodiment, the LSD is a defect in lysosomal enzyme protection. Defects in lysosomal enzyme protection include, but are not limited to, galactosialidosis (protective protein cathepsin A (PPCA) defect). In one embodiment, the LSD is a defect in soluble non-enzymatic lysosomal proteins. Defects in soluble non-enzymatic lysosomal proteins include, but are not limited to, GM2 activator protein deficiency (variant AB), Niemann-Pick Disease Type C2 (NPC2), sphingolipid activator protein (SAP) deficiency. In one embodiment, the LSD is a transmembrane (non-enzyme) protein defect.

Transmembrane (non-enzyme) protein defects include, but are not limited to, Danon disease (lysosome-associated membrane protein 2 (LAMP2) defect), NPC (NPC1 defect), cystinosis (cystinosin defect), infantile free sialic acid storage disease (ISSD; sialin defect), Salla disease (free sialic acid storage; sialin defect), juvenile neuronal ceroid lipofuscinosis (CLN3, Batten disease), adult neuronal ceroid lipofuscinosis (Kufs disease; Adult NCL; palmotoyl-protein thioesterase-1 deficiency (Type A); Cathepsin F deficiency (Type B)), neuronal ceroid lipofuscinoses (NCL) (CLN6, CLN7, and CLN8) and mucolipidosis type IV (mucolipin defect). In one embodiment, the LSD is Niemann-Pick Type C1 or Niemann- Pick Type C2.

In one embodiment, the LSD is an unclassified defect. Unclassified defects include, but are not limited to, neuronal ceroid lipofuscinoses (NCL) (CLN5 and CLN9).

The LSD to be treated by the compositions and methods of the invention may be any of the neuronal ceroid lipofuscinoses, primary glycosphingolipidoses (i.e. Gaucher, Fabry, GM1 , GM2 gangliosidoses, Krabbe and metachromatic leukodystrophy (MLD)), Farber disease and multiple sulphatase deficiency. In one embodiment, the LSD has a significant central nervous system (CNS) involvement. For example, the LSD may be chosen from NPC, Tay-Sachs disease, Sandhoff disease, GM1 gangliosidosis or Fabry disease.

In one embodiment, the LSD is Niemann-Pick disease type A. In another embodiment, the LSD is Niemann-Pick disease type B. In another embodiment, the LSD is Niemann-Pick type C (C1 or C2) disease. The neurodegenerative disease may, but need not, be associated with lysosomal dysfunction (e.g., lysosomal storage defect). Neurodegenerative diseases, according to the present disclosure, not associated with lysosomal dysfunction include, but are not limited to, Alexander's disease, Alper's disease, cerebral palsy, Cockayne syndrome, corticobasal degeneration, HIV-associated dementia, Kennedy's disease, neuroborreliosis, primary lateral sclerosis, , Refsum's disease, Schilder's disease, subacute combined degeneration of spinal cord secondary to pernicious anaemia, hereditary motor and sensory neuropathy with proximal dominance, Wobbly Hedgehog Syndrome (WHS), progressive muscular atrophy (Duchenne-Aran muscular atrophy), progressive bulbar palsy, pseudobulbar palsy, HIV-associated neurocognitive disorders (HAND), Vascular Parkinsonism, lower body Parkinson's syndrome, cerebellar downbeat nystagmus, and cerebellar ataxia, which includes Spinocerebellar ataxia (SCA) 4, Spinocerebellar ataxia (SCA) 5 (Lincoln's Ataxia), Spinocerebellar ataxia (SCA) 8, Spinocerebellar Ataxia (SCA) 10, Spinocerebellar Ataxia (SCA) 1 1 , Spinocerebellar Ataxia (SCA) 12, Spinocerebellar Ataxia (SCA) 13, Spinocerebellar Ataxia (SCA) 14, Spinocerebellar Ataxia (SCA) 15/16, Spinocerebellar Ataxia (SCA) 18 (sensory/motor neuropathy with ataxia), Spinocerebellar Ataxia (SCA) 19/22, Spinocerebellar Ataxia (SCA) 20, Spinocerebellar Ataxia (SCA) 21 , Spinocerebellar Ataxia (SCA) 23, Spinocerebellar Ataxia (SCA) 25, Spinocerebellar Ataxia (SCA) 26, Spinocerebellar Ataxia (SCA) 27, Spinocerebellar Ataxia (SCA) 29,

Spinocerebellar Ataxia (SCA) 30, Spinocerebellar Ataxia (SCA) 31 , Spinocerebellar Ataxia (SCA) 32, Spinocerebellar Ataxia (SCA) 35, Spinocerebellar Ataxia (SCA) 36, Episodic Ataxia (EA) 1 , Episodic Ataxia (EA) 2, Episodic Ataxia (EA) 3, Episodic Ataxia (EA) 4, Episodic Ataxia (EA) 5, Episodic Ataxia (EA) 6, Episodic Ataxia (EA) 7, Spinocerebellar Ataxia (SCA) 28, Spinocerebellar Ataxia (SCA) 24 (spinocerebellar ataxia autosomal recessive type 4 (SCAR4); Spinocerebellar ataxia with saccadic intrusions), Tabes dorsalis, Ataxia with Oculomotor Apraxia Type 1 (AOA1), Ataxia with Oculomotor Apraxia Type 2 (AOA2), Ataxia with Oculomotor Apraxia Type 4 (AOA4), spinocerebellar ataxia autosomal recessive type 10 (SCAR 10), mitochondrial recessive ataxia syndrome

(MIRAS), Myclonic Epilepsy Myopathy Sensory Ataxia (MEMSA), Sensory Ataxic

Neuropathy Dysarthria Opthalmoparesis (SANDO), infantile-onset spinocerebellar ataxia, Hereditary Spastic Paraplegia 7 (HSP SPG7 gene), mitochondrial myopathy,

encephalopathy, lactacidosis, stroke syndrome (MELAS), myoclonic epilepsy with ragged red fibers (MERRF), neurogenic muscle weakness, ataxia, and retinitis pigmentosa

(NARP), Kearns-Sayre (KSS), Fragile X tremor/ataxia syndrome (FXTAS), Arts Syndrome, X-linked Spinocerebellar Ataxia 1 , X-linked Spinocerebellar Ataxia 2, X-linked

Spinocerebellar Ataxia 3, X-linked Spinocerebellar Ataxia 4 or X-linked Spinocerebellar Ataxia 5, Christianson type X-linked syndromic mental retardation, X-linked sideroblastic anemia, Idiopathic Late-Onset Cerebellar Ataxia, Sporadic Adult-Onset Ataxia of Unknown Etiology (SAOA), and cerebellar ataxia, neuropathy, vestibular areflexia syndrome

(CANVAS). In one embodiment, the neurodegenerative disease not associated with lysosomal dysfunction is corticobasal degeneration, SCA 28, and AOA4. As mentioned above, many neurodegenerative diseases are associated with lysosomal dysfunction, which includes both neurodegenerative lysosomal storage disorders (LSDs) and many other neurodegenerative diseases where links to lysosomal defects have been suggested. See, e.g., Boman et al., Journal of Parkinson's Disease, vol. 6, no. 2, pp. 307- 315 (May 2016); Makioka et al., Neuroreport, 23(5):270-276 (March 2012); Orr et al., Alzheimer's Research & Therapy, 5:53 (Oct. 2013); Barlow et al., Proc. Nat'l. Acad. Sci. USA, 18;97(2):871-6 (2000).

In one embodiment, the neurodegenerative disease is associated with lysosomal dysfunction (e.g., lysosomal storage defect). Neurodegenerative diseases, according to the present disclosure, associated with lysosomal dysfunction include, but are not limited to, alcoholism, Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Canavan disease, frontotemporal lobar degeneration, Huntington's disease, Lewy body dementia, multiple system atrophy (MSA-P/MSA-C), multiple sclerosis, narcolepsy, Parkinson's Disease, Smith Lemli Opitz Syndrome (SLOS) (an inborn error of cholesterol synthesis), Tangier disease, Pelizaeus-Merzbacher Disease, Pick's disease, frontotemporal dementia and parkinsonism linked to chromosome 17, prion diseases, including scrapie, transmissible mink encephalopathy, chronic wasting disease, bovine spongiform encephalopathy (BSE), feline spongiform encephalopathy, exotic ungulate encephalopathy, kuru, Creutzfeldt- Jakob disease, Gerstmann-Straussler-Scheinker syndrome, and fatal familial insomnia, progressive supranuclear palsy, spinal muscular atrophy, neurodegenerative LSDs, and cerebellar ataxia, which includes Spinocerebellar Ataxia (SCA) 1 , Spinocerebellar Ataxia (SCA) 2, Spinocerebellar Ataxia (SCA) 3 (Machado-Joseph disease), Spinocerebellar Ataxia (SCA) 6, Spinocerebellar Ataxia (SCA) 7, Spinocerebellar Ataxia (SCA) 17, dentatorubral-pallidoluysian atrophy, Autosomal Recessive Spastic Ataxia of Charlevoix- Saguenay (ARSACS), autosomal recessive cerebellar ataxia type 1 (Recessive Ataxia of Beauce (RAB), SYNE-1 mutation), autosomal recessive cerebellar ataxia type 2

(spinocerebellar ataxia autosomal recessive 9, SCAR9), ataxia with vitamin E deficiency (AVED), ataxia telangiectasia (Louis Barr disease), Freidreich's ataxia (FRDA), and ataxia with coenzyme Q10 deficiency. In one embodiment, the neurodegenerative disease associated with lysosomal dysfunction is chosen from alcoholism, Alzheimer's disease, amyotrophic lateral sclerosis (ALS), Canavan disease, frontotemporal lobar degeneration, Huntington's disease, multiple system atrophy (MSA-P/MSA-C), multiple sclerosis, narcolepsy, Parkinson's Disease, Smith Lemli Opitz Syndrome (SLOS) (an inborn error of cholesterol synthesis), Tangier disease, Pelizaeus-Merzbacher Disease, Pick's disease, frontotemporal dementia, frontotemporal dementia with parkinsonism, prion diseases, progressive supranuclear palsy, and spinal muscular atrophy. In one embodiment, the neurodegenerative disease associated with lysosomal dysfunction is chosen from ALS, MSA-P, MSA-C, frontotemporal dementia with parkinsonism, progressive supranuclear palsy, SCA 28, SCA 1 , and Alzheimer's disease.

Neurodegenerative LSDs are characterized by the accumulation of undigested or partially digested macromolecules resulting in cellular dysfunction and neurodegeneration, which is often progressive leading to physical disability and/or mental deterioration. They tend to present in the first few years of life and the severe progression results in frequent hospitalization. If left untreated, patients often die in their mid-teens. Adult-onset patients have also been described. Neurodegenerative LSDs, according to the present disclosure, include, but are not limited to, neuronal ceroid lipofuscinoses (Types 1-10), Gaucher disease Type 2/3 (neuronopathic), Krabbe disease, multiple sulfatase deficiency, mucolipidoses, including mucolipidosis I, mucolipidosis II, and mucolipidosis IV, Niemann- Pick Disease Type A, Niemann-Pick Disease Type B, Niemann-Pick Disease Type C, Infantile-Onset Pompe Disease, Late-Onset Pompe Disease, Tay-Sachs disease, Sandhoff disease, Farber disease, galactosialidosis, Fabry disease, Schindler disease, GM1 gangliosidosis, AB variant GM2 gangliosidosis, metachromatic leukodystrophy

(MLD), mucopolysaccharidoses, including MPS IH, MPS IS, MPS IH-S, MPS II, MPS IIIA, MPS NIB, MPS NIC, MPS MID, and MPS VII, beta-mannosidosis, aspartylglucosaminuria, fucosidosis, Salla disease, infantile free sialic acid storage disease (ISSD), and Danon disease. In one embodiment, the neurodegenerative LSD is chosen from NPC, NPA, mucolipidosis II, MPS NIB, aspartylglucosaminuria, mucolipidosis IIIA, MPS VII, Sandhoff disease, Tay-Sachs disease, the AB variant of Tay-Sachs disease, and GM1

gangliosidosis. In one embodiment, the neurodegenerative disease is not chosen from a neurodegenerative LSD.

In one embodiment, the neurodegenerative disease is a Motor Neuron Disease. In one embodiment, the Motor Neuron Disease is chosen from primary lateral sclerosis, progressive muscular atrophy, progressive bulbar palsy, pseudobulbar palsy, ALS, Alzheimer's disease, Canavan disease, frontotemporal lobar degeneration, Huntington's disease, multiple sclerosis, narcolepsy, Parkinson's Disease, Pelizaeus-Merzbacher disease, and spinal muscular atrophy.

In one embodiment, the neurodegenerative disease is cerebellar ataxia. In one

embodiment, the neurodegenerative disease is Niemann-Pick disease. In one

embodiment, the neurodegenerative disease is Niemann-Pick type C. In one embodiment, the neurodegenerative disease is Niemann-Pick type A. In one embodiment, the neurodegenerative disease is parkinsonism. In one embodiment, the neurodegenerative disease is neuronopathic Gaucher disease. In one embodiment, the neurodegenerative disease is Tay-Sachs disease. In one embodiment, the neurodegenerative disease is Sandhoffs disease. In one embodiment, the neurodegenerative disease is Fabry disease. In one embodiment, the neurodegenerative disease is GM1 gangliosidosis. In one embodiment, the neurodegenerative disease is Louis-Barr syndrome. In one embodiment, the neurodegenerative disease is Alzheimer's disease. In one embodiment, the

neurodegenerative disease is Parkinson's disease. In one embodiment, the

neurodegenerative disease is multiple system atrophy. In one embodiment, the

neurodegenerative disease is multiple system atrophy type C (MSA-C). In one

embodiment, the neurodegenerative disease is multiple system atrophy type P (MSA-P). In one embodiment, the neurodegenerative disease is fronto-temporal dementia. In one embodiment, the neurodegenerative disease is fronto-temporal dementia with

parkinsonism. In one embodiment, the neurodegenerative disease is lower body

Parkinson's syndrome. In one embodiment, the neurodegenerative disease is amyotrophic lateral sclerosis (ALS). In one embodiment, the neurodegenerative disease is corticobasal- degeneration-syndrome. In one embodiment, the neurodegenerative disease is

progressive supranuclear palsy. In one embodiment, the neurodegenerative disease is cerebellar downbeat nystagmus. In one embodiment, the neurodegenerative disease is SCA 28. In one embodiment, the neurodegenerative disease is ataxia telangiectasia. In one embodiment, the neurodegenerative disease is SCA 1. In one embodiment, the neurodegenerative disease is AOA4.

Major symptoms of Parkinson's Disease (PD) include rigidity, tremor, and slow movement. There are other diseases in which these symptoms are prevalent. These diseases, and PD itself, fall under the umbrella term Parkinsonism. PD can be referred to as Primary

Parkinsonism. Other examples of Parkinsonisms include: Multiple System Atrophy; Progressive Supranuclear Palsy; Normal pressure hydrocephalus; and Vascular or arteriosclerotic parkinsonism. Those diseases that can be classed as Parkinsonisms, but are not PD, can also be referred to as "Parkinson-Plus Syndromes". Unlike PD patients, individuals with Parkinson-Plus Syndromes do not respond to L-Dopa. The term

"parkinsonism" as used herein may refer to a motor syndrome whose main symptoms are tremor at rest, stiffness, slowing of movement and postural instability. Parkinsonian syndromes can be divided into four subtypes, according to their origin: primary or idiopathic; secondary or acquired; hereditary parkinsonism; and Parkinson plus syndromes or multiple system degeneration. In one embodiment, the parkinsonism is a Parkinson plus syndrome or multiple system degeneration.

In one embodiment, the parkinsonism is vascular (arteriosclerotic) Parkinsonism, lower- body Parkinsonism, Multiple System Atrophy with predominant parkinsonism (MSA-P), Multiple System Atrophy with cerebellar features (MSA-C; Sporadic olivopontocerebellar atrophy (OPCA)), Shy-Drager syndrome, Progressive Supranuclear Palsy (Steele-

Richardson-Olszewski syndrome), Lewy body dementia, Pick's disease, or frontotemporal dementia and parkinsonism linked to chromosome 17.

Niemann-Pick diseases are a heterogeneous group of autosomal recessive LSDs.

Common cellular features include abnormal sphingomyelin (SM) storage in mononuclear phagocytic cells and parenchymal tissues, as well as (hepato)splenomegaly. Among the three main subgroups of Niemann-Pick disease (A-C), NPC (previously classified as NPC and NPD and now appreciated to be a single disease) is classified as a fatal neurovisceral LSD caused by abnormal intracellular cholesterol transport-induced accumulation of unesterified cholesterol in late endosome/lysosomal compartments. Outside the CNS, the cellular characteristics of NPC include abnormal accumulation of unesterified cholesterol and other lipids (e.g. GSLs) within late endosome/lysosomal compartments. Conversely, there is no net elevation in cholesterol in the CNS (although it does have an altered distribution) but there are highly elevated levels of GSLs. Progressive neurodegeneration is particularly characterised by sequential degeneration of GABAergic Purkinje neurons in the cerebellum, which parallels the onset and progression of cerebellar ataxia and other aspects of neurological dysfunctions seen during the course of NPC. Genetic studies have shown that NPC disease is caused by mutations in either the Npc1 or Npc2 genes. The precise mechanistic link between these two genes remains unknown and the functional roles of these proteins remains enigmatic. NPC1 encodes a multimembrane spanning protein of the limiting membrane of the late endosome/lysosome, whereas NPC2 is a soluble cholesterol binding protein of the lysosome. When NPC 1 is inactivated, sphingosine is the first lipid to be stored, suggesting that NPC1 plays a role in the transport of sphingosine from the lysosome, where it is normally generated as part of sphingolipid catabolism. Elevated sphingosine in turn causes a defect in calcium entry into acidic stores resulting in greatly reduced calcium release from this compartment. This then prevents late endosome-lysosome fusion, which is a calcium dependent process, and causes the secondary accumulation of lipids (cholesterol, sphingomyelin and

glycosphingolipids) that are cargos in transit through the late endocytic pathway. Other secondary consequences of inhibiting NPC1 function include defective endocytosis and failure to clear autophagic vacuoles. It has been shown that the NPC1/NPC2 cellular pathway is targeted by pathogenic mycobacteria to promote their survival in late endosomes.

The NPC mouse model shares a number of pathological features with, e.g., Alzheimer's disease (AD). Microtubule-associated protein 1 A/1 B-light chain 3- phosphatidylethanolamine conjugate (LC3-II) levels have previously been reported to be elevated in the NPC mouse. LC3-II is a marker of autophagosome formation, and increased levels of LC3-II can reflect impaired clearance of autophagic vacuoles.

Autophagosomes are formed, but are not cleared. Autophagy is impaired in AD, and AD brains exhibit increased levels of LC3-II. In addition, amyloid precursor protein (APP) is the precursor molecule whose proteolysis generates beta amyloid (Αβ). Αβ plaques are a hallmark of the AD brain and have been proposed to be a causative factor in disease pathology. Amyloid precursor protein C-terminal fragments (APP-CTFs), which are an intermediate in the proteolysis of APP to Αβ, accumulate in the AD brain and also progressively accumulate in the brains of NPC1 mice.

Tay-Sachs disease is a fatal hereditary disorder of lipid metabolism characterised especially in CNS tissue due to deficiency of the A isozyme of β-hexosaminidase.

Mutations in the HEXA gene, which encodes the a subunit of β-hexosaminidase, cause the A isozyme deficiency. Tay-Sachs is a prototype of a group of disorders, the GM2 gangliosidoses, characterized by defective GM2 ganglioside degradation. The GM2 ganglioside (monosialylated ganglioside 2) accumulates in the neurons beginning already in fetal life.

Sandhoff disease results from a deficiency of both the A and B (basic) isozymes of β- hexosaminidase. Mutations in the HEXB gene, which encodes the β subunit of β- hexosaminidase, cause the B isozyme deficiency.

GM1 gangliosidosis is caused by a deficiency of β-galactosidase, which results in lysosomal storage of GM1 ganglioside (monosialylated ganglioside 1).

Fabry disease is caused by a deficiency of a-galactosidase, which results in lysosomal storage of a ceramide trihexoside.

In one embodiment, the neurodegenerative disease is not cerebellar ataxia. In one embodiment, the neurodegenerative disease is not Niemann Pick disease. In one embodiment, the neurodegenerative disease is not Niemann Pick type C disease. In one embodiment, the neurodegenerative disease is not cerebellar ataxia or Niemann Pick disease (e.g., Niemann Pick type C disease).

In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats weight loss, gait deterioration, and/or motor function deterioration associated with

Niemann-Pick disease (e.g., Niemann-Pick type C or A) or mucolipidosis type II. For example, the leucine, or a pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of weight loss, gait deterioration, and/or motor function deterioration associated with Niemann-Pick disease (e.g. Niemann-Pick type C or A) or mucolipidosis type II. In one embodiment, the weight loss, gait deterioration, and/or motor function deterioration is associated with Niemann- Pick type A or mucolipidosis type II. In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats gait deterioration, motor function deterioration and/or reduced mobility associated with

Sandhoff s disease. For example, the leucine, or a pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of gait deterioration, motor function deterioration, and/or reduced mobility associated with Sandhoff s disease.

In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats reduced co-ordination, tremors, reduced mobility, cognitive impairment, and/or gait deterioration associated with Tay-Sachs disease. For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of reduced co-ordination, tremors, reduced mobility, cognitive impairment, and/or gait deterioration associated with Tay-Sachs disease. In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats speech deterioration (e.g., fluency of speech and/or modulation of voice), gait

deterioration, reduced mobility, reduced swallowing functions, and/or paresis associated with amyotrophic lateral sclerosis (ALS). For example, the leucine, or a pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of speech deterioration (e.g., fluency of speech and/or modulation of voice), gait deterioration, reduced mobility, reduced swallowing functions, and/or paresis associated with ALS. In another embodiment, the leucine, or the pharmaceutically acceptable salt thereof treats reduced sleep quality associated with ALS. For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of reduced sleep quality associated with ALS.

In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats speech deterioration, gait deterioration, and/or increased propensity to falls associated with multisystemic atrophy cerebellar type (MSA-C). For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of speech deterioration, gait deterioration, and/or increased propensity to falls associated with MSA-C.

In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats gait deterioration, increased propensity to falls, and/or speech deterioration associated with fronto-temporal dementia with parkinsonism. For example, the leucine, or the

pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of gait deterioration, increased propensity to falls, and/or speech deterioration associated with fronto-temporal dementia with

parkinsonism.

In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats increased propensity to falls and/or gait deterioration associated with corticobasal- degeneration-syndrome. For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of increased propensity to falls and/or gait deterioration associated with corticobasal-degeneration-syndrome. In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats gait deterioration associated with progressive supranuclear palsy. For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of gait deterioration associated with progressive supranuclear palsy. In one embodiment, the leucine, or the pharmaceutically acceptable salt thereof, treats oscillopsia, deterioration of spatial orientation, deterioration of visual acuity, and/or increase in postural sway associated with cerebellar downbeat nystagmus. For example, the leucine, or the pharmaceutically acceptable salt thereof, may delay onset of, reduce the severity of or eliminate, or delay or reverse the progression of oscillopsia, deterioration of spatial orientation, deterioration of visual acuity, and/or increase in postural sway associated with cerebellar downbeat nystagmus.

There is also provided a method of treating a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease in a subject in need thereof, the method comprising administering a therapeutically effective amount of leucine, or a pharmaceutically acceptable salt thereof, to the subject.

A "therapeutically effective amount" of an agent is any amount which, when administered to a subject, is the amount of agent that is needed to produce the desired effect, which, for the present disclosure, can be therapeutic and/or prophylatic. The dose may be determined according to various parameters, such as the specific form of leucine used; the age, weight and condition of the patient to be treated; the type of the disease; the route of administration; and the required regimen. A physician will be able to determine the required route of administration and dosage for any particular patient. For example, a daily dose may be from about 10 to about 225 mg per kg, from about 10 to about 150 mg per kg, or from about 10 to about 100 mg per kg of body weight. Also disclosed is a kit for treating a LSD or a neurodegenerative disease in a subject, comprising a means for diagnosing or prognosing the disease/disorder, and leucine, or a pharmaceutically acceptable salt thereof.

The means for diagnosing or prognosing a LSD or a neurodegenerative disease may include a specific binding agent, probe, primer, pair or combination of primers, an enzyme or antibody, including an antibody fragment, which is capable of detecting or aiding in the detection of a LSD or a neurodegenerative disease, as defined herein. The kit may comprise LysoTracker ^® , which is a fluorescent marker and is commercially-available from both Invitrogen and also Lonza. The LysoTracker ^® may be blue, blue-white, yellow, green or red. The kit also comprises leucine, or a pharmaceutically acceptable salt thereof, as defined herein. The kit may further comprise buffers or aqueous solutions. The kit may further comprise instructions for using the leucine, or pharmaceutically acceptable salt thereof in a method of the invention.

In a further embodiment, there is disclosed leucine, or a pharmaceutically acceptable salt thereof, for use in a method of providing neuroprotection in a subject in need thereof (e.g., a subject having, suspected of having, or at risk of having a LSD or a neurodegenerative disease).

"Neuroprotection" and its cognates, as used herein, refer to prevention, a slowing in, and/or a reversed progression of neurodegeneration, including, but not limited to, progressive loss of neuronal structure, progressive loss of neuronal function, and/or progressive neuronal death. Providing neuroprotection may result in delaying onset of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a

neurodegenerative disease that would otherwise be expected to manifest according to typical disease progression, reducing the severity of a LSD or a neurodegenerative disease or reducing the severity of or eliminating one or more existing symptoms associated with a LSD or a neurodegenerative disease, delaying progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease over time as compared to typical disease progression, and/or reversing progression of a LSD or a neurodegenerative disease, or one or more symptoms of a LSD or a neurodegenerative disease over time. The time over which neuroprotection is provided may coincide with the duration of treatment as described herein. The treatment may provide neuroprotection over a duration of, for example, about seven days or more, about two weeks or more, about three weeks or more, about one month or more, about six weeks or more, about seven weeks or more or about two months or more. The treatment may provide neuroprotection over a duration of, for example, about three months or more, about four months or more, about five months or more or about six months or more. It may provide neuroprotection over a duration of, for example, about 1 year or more, about 2 years or more, about 3 years or more, about 4 years or more, about 5 years or more, or about 10 years or more. The treatment may provide neuroprotection over the lifetime of the patient.

As evidenced by the Examples, the inventors believe that leucine is acting as a

neuroprotective agent and so inhibiting the neurodegeneration that would otherwise be expected to manifest.

In another embodiment, a method of providing neuroprotection in a subject in need thereof (e.g., a subject having, suspected of having, or at risk of having a neurodegenerative disease or a LSD) comprises administering a therapeutically effective amount of leucine, or a pharmaceutically acceptable salt thereof, to the subject.

Also disclosed is a kit for providing neuroprotection in a subject in need thereof (e.g., a subject having, suspected of having, or at risk of having a LSD or a neurodegenerative disease), the kit comprising a means for diagnosing or prognosing the disease/disorder, and leucine, or a pharmaceutically acceptable salt thereof.

The present disclosure further includes a kit for use in the methods of the invention, e.g., treating a LSD or a neurodegenerative disease in a subject, providing neuroprotection in said subject, improving motility and cognitive function, e.g., in the elderly, the kit comprising one or more containers comprising leucine or a pharmaceutically acceptable salt thereof, e.g., one, two, three, four, five, or six or more containers/bottlers or sachets, and at least one container comprising a liquid such as liquid carriers for preparing solutions, supsensions, emulsions, syrups, or elixirs for formulating the leucine for administration to a subject in need thereof.

The present disclosure further includes the use of leucine, or a pharmaceutically acceptable salt thereof, as a neuroprotective agent in a subject in need thereof (e.g., a subject having, suspected of having, or at risk of having a LSD or a neurodegenerative disease).

In at least some embodiments, leucine, or a pharmaceutically acceptable salt thereof may be used to improve balance in a subject, wherein the subject has impaired balance associated with ageing. According to the present disclosure, the impaired balance associated with ageing is not vertigo.

In some embodiments, the subject may, for example, not have benign paroxysmal positional vertigo (BPPV); vestibular neuritis; vertigo related to Meniere's disease,

Wallenberg's syndrome, cerebellar ischemia, perilymph fistula or acoustic neurinoma; or recurring vertigo of traumatic or toxic origin.

According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, may be used to treat balance disorder associated with ageing.

According to the present disclosure, leucine, or pharmaceutically acceptable salt thereof, may be used to increase a subject's stability, for example when standing and/or walking, wherein the subject has decreased stability associated with ageing. According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, may be used to reduce a subject's unsteadiness whilst walking, wherein the subject has increased unsteadiness associated with ageing.

According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, may be used to treat a subject with impaired gait wherein the impaired gait is associated with ageing. The subject may have senile gait disorder. According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, may be used to increase gait velocity and or cadence in a subject wherein the subject has impaired gait velocity and or cadence associated with ageing. According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof, may be used to treat a subject that has a pre-disposition to falls, wherein the predisposition to falls is associated with ageing

Cognitive function may also be assessed using reaction speed and/or alertness tests, such as the Psychomotor Vigilance Task (e.g. as disclosed in the Examples). This test assesses components including fine motor skills; psychomotor speed; lapses of attention; instability of alertness; and impulsivity induced by fatigue.

For example, the Psychomotor Vigilance Task (PVT) is a sustained-attention, reaction- timed task that measures the speed with which subjects respond to a visual stimulus. The subject monitors a screen and presses the screen as quickly as possible upon the appearance of visual stimuli. The visual stimuli will then disappear and reappear (at irregular time intervals) e.g., 10 times over the course of the test, with the subject touching the screen as quickly as possible upon each reappearance. Test performance is quantified from an average of the e.g. 10 reaction times.

Any change in cognitive function, for example, over time or through treatment, can be monitored by using one or more of these well-established tests at two or more time points and comparing the results.

In at least some embodiments, a subject shows a positive change in their ability to perform a symbolic operation, for example, to perceive, remember, create a mental image, have clarity of thought, be aware, to reason, think or judge. The positive change can be measured using any of the aforementioned tests on two or more occasions, for example, a first occasion to measure baseline cognitive function and a second occasion to measure cognitive function following a period of time (in which treatment may have been

administered). Cognitive function could be said to be improved when at least about a 5% increase in performance in the relevant test, between two time points, is observed. For example, an increase in performance of at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or at least about 100% in the relevant test, between the two time points, is observed. Further for example, an increase in performance of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100% in the relevant test, between the two time points, is observed. The two time points may be one week apart, two weeks apart, three weeks apart, four weeks apart, two months apart, three months apart, four months apart, five months apart or even six months apart. Treatment may be administered during the intervening period. Thus, as an example, "improving cognitive function" can mean that the subject will demonstrate an at least about 5% increase in performance from a baseline measurement, as measured using the well-established Wechsler Adult Intelligence Scale. For example, the subject may demonstrate an increase in performance in this test of at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or at least about 100%. Further for example, the subject may demonstrate an increase in performance in this test of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90% or at least 100%.

According to the present disclosure, leucine, or a pharmaceutically acceptable salt thereof may be used to increase reaction speed, for example the speed in which a subject responds to a visual stimulus.

In one embodiment, the subject has a decrease in cognitive function associated with ageing.

Also envisaged and encompassed by the present disclosure is the prevention of impaired mobility and/or cognitive decline in the elderly, using leucine as described herein. Thus, an age-related decrease in mobility and/or cognitive function may never occur at all, using leucine as described herein. In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject to improve cognitive function, mobility, or cognitive function and mobility. In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject to treat an age-related decrease in cognitive function and/or mobility.

In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject that has a decrease in cognitive function associated with ageing and/or a mobility disorder associated with ageing.

In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject, wherein the subject is a human aged 40 or over; 50 or over; 60 or over; 70 or over; 75 or over; 80 or over; 85 or over; 90 or over; or 95 or over.

In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject, wherein the subject is an elderly subject.

In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject, wherein the method improves cognitive function in said subject.

In at least some embodiments, the method comprises administering leucine, or a pharmaceutically acceptable salt thereof, to a subject, wherein the method improves mobility in said subject. In at least some embodiments, the cognitive function is one or more selected from the group consisting of perception, memory, creation of imagery, awareness, reasoning, thinking and capacity for judgment. In at least some embodiments, leucine or a pharmaceutically acceptable salt thereof is in racemate form, in an enantiomeric excess of the L-enantiomer or in an enantiomeric excess of the D-enantiomer. In at least some embodiments, the method comprises administering leucine in a dose from 0.5 to 15 g, between 1.5 g and 10 g, for example between 4 g and 10 g per day.

All of the features described herein (including any accompanying claims, abstract and drawings), and/or all of the steps of any method so disclosed, may be combined with any of the above aspects in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Examples

The invention will now be explained in further detail in the following Examples, which demonstrate the utility of leucine and acetyl-leucine in treating a LSD or a

neurodegenerative disease in a subject and providing neuroprotection in said subject, and further demonstrate the utility of leucine and acetyl-leucine in improving motility and cognitive function, for example in the elderly.

Example 1

In Vivo Mouse Study - Methods

Mouse Model

This study made use of an authentic mouse model of NPC, the A/pc7 ^{" _} (BALB/cNctr- Npc1 ^m1N /J) mouse, which is null for the NPC1 protein and displays all the hallmarks of the clinical disease (Loftus, 1997).

This mutant strain arose spontaneously and has a lifespan in the range of 10-14 weeks and therefore has a course of disease more acute that the vast majority of patients. The mutant mouse has been exploited successfully, not only for determining the ontogeny of disease and underlying pathogenic mechanisms, but also for the evaluation of

experimental therapies. Analyses using these mice have been undertaken at the whole animal, cellular, and molecular levels (Baudry, 2003; Smith, 2009; Cologna, 2014;

Cologna, 2012). It is the most intensively studied animal model of NPC.

Prior to about 4-5 weeks of age NpcV ^~ mice have no discernible behavioural indication of disease that distinguishes them from wild-type littermates. First indications of behavioural deficits, such as tremor and ataxic gait, appear by weeks 5-6; by weeks 7-8 defects in motor coordination become more apparent, and by 9-10 weeks ataxia is advanced and accompanied by increased loss in weight and poor coat condition as feeding and drinking becomes difficult (humane end point applied) (Smith, 2009).

Wild-type (Npc1 ^+/+ ) littermates were used as a control.

Treatment Protocol

A group of Npc1 ^~ ' ^~ mice and a group of Npc1 ^+/+ mice were treated with 0.1 g/kg acetyl-DL- leucine, provided mixed in the mouse chow, from weaning (three weeks of age). Separate groups of Npc1 ^~ ' ^~ and Npc1 ^+/+ mice were left untreated, as controls.

Coat Condition

The coat condition of /Vpc7 ^{_ ~} mice, with and without acetyl-DL-leucine treatment, was compared by simple observation of the mice at nine weeks of age. Weight Data

Animals were weighed twice a week. Weights were averaged (mean) across all mice in each group and compared.

Gait Analysis

Gait analysis was performed on mice at eight weeks of age using a CatWalk ^® 15.0 system according to manufacturer's instructions (Noldus, Nottingham, UK). Five runs were recorded per animal.

CatWalk ^® parameters measured were: 1. Stand Mean: average duration (s) of paws in contact with glass plate;

2. Step Cycle: duration (s) between two consecutive contacts of the same paw;

3. Duty Cycle: percentage of time paws in contact with plate compared with time to complete a step cycle; 4. Step Sequence (AB): percentage of time spent walking in LF-RH-RF-LH alternating pattern (LF: left front; RH: right hind; RF: right front; LH left hind);

5. Cadence: step per seconds in a trial;

6. Diagonal Support: percentage of time with simultaneous contact of diagonal paws with the glass plate (RF&LH or RH&LF). Motor Function Analysis

Motor function analysis was performed on mice at eight and nine weeks of age using an Open Field Activity Monitor according to manufacturer's instructions (Linton Instruments, Amlogger Software). Each mouse was placed in a plastic cage with bedding and analysed for five minutes. Rears were counted manually. Motor function parameters measured were:

1. Centre Rearing: mice rearing on hind legs unsupported;

2. Rearing: mice rearing on hind legs with and without the support of cage walls;

3. Activity: regular movement of the animal including walks;

4. Front to Back (FR) count: movement of the animal from front to back of the cage; 5. Active Time: duration (s/min) of activeness regardless of movement;

6. Mobile Time: duration (s/min) of mobility;

7. Rearing Time: duration of any rearing. Results

Coat Condition Figure 1 B shows an untreated Npc1 ^~ ' ^~ age matched littermate. /Vpc ^_ mice were observed as having poor coat condition at nine weeks of age, as feeding and drinking had become difficult (see Figure 1 B).

In distinct contrast, Figure 1A shows an Npc '- mouse treated with acetyl-DL- leucine from weaning. NpcV ^~ mice treated with acetyl-DL-leucine had a smooth and glossy coat, reminiscent of wild-type (Npc1 ^+/+ ) littermates (see Figure 1A).

Weight Data

As can be seen in Figure 2A, wild-type (Npc1 ^+/+ ) mice progressively put on weight for the duration of the study, i.e. from three weeks to 10 weeks of age. Further, Figure 2A shows the mean weight per group of mice at each point in time (/Vpc7 ^_/~ untreated, n = 1 ; Npc ' ^~ acetyl-DL-leucine 0.1 g/kg, n = 3; Npc1 ^+/+ untreated, n = 3; Npc1 ^+/+ acetyl-DL-leucine 0.1 g/kg, n = 2).

Treatment with acetyl-DL-leucine had no significant effect on this weight gain.

/Vpc7 ^{_ ~} mice initially put on weight, largely in the same manner as Npc1 ^+/+ controls.

However, the NpcV ^~ mice then began to lose weight from six weeks of age. At the end of the study (10 weeks of age), the mice weighed nearly as little as at just four weeks of age.

Treatment with acetyl-DL-leucine delayed these weight loss symptoms by two weeks compared to the untreated group.

A comparison of the weight changes in /Vpc7 ^_/~ mice, with and without acetyl-DL-leucine treatment, is shown in Figure 2B. In particular, Figure 2 B shows the change in weight (%) per group of mice at each point in time, for the /Vpc7 ^_/~ mice only. The beneficial effect of acetyl-DL-leucine treatment in delaying weight loss is clearly evident from this Figure.

Gait Analysis

The results of the gait analysis are shown in Figure 3. Diagonal support, cadence and step sequence data are shown in Figures 3A - 3C, respectively. Figures 3D and 3E show front paw (FP) data (stand mean and step cycle in Figure 3D; duty cycle in Figure 3E). Figures 3F and 3G show hind paw (HP) data (stand mean and step cycle in Figure 3F; duty cycle in Figure 3G). Data are presented as mean ± SEM. n=3 for Npc1 ^+/+ untreated, n=2 for Npc1 ^+/+ treated, n=1 for NpcV ^~ untreated (hence no statistical analysis performed), n=3 for Npc treated.

The first bar in each graph shows the gait properties of wild-type (Npc1 ^+/+ ) mice.

The second bar in each graph shows the gait properties of wild-type (Npc1 ^+/+ ) mice treated with acetyl-DL-leucine. There was no significant difference in gait properties between these mice and their untreated littermates.

The third bar in each graph shows the gait properties of an Npc mouse. On the whole, this mouse showed poor gait compared to Npc1 ^+/+ mice. The mouse spent extremely little time, if any, in diagonal support (Figure 3A) or step sequence (Figure 3C), and its hind paw function in stand mean (Figure 3F) and duty cycle (Figure 3G) were also drastically hindered.

The fourth bar in each graph shows the gait properties of NpcV ^~ mice treated with acetyl- DL-leucine. These mice demonstrated significantly improved gait compared to their untreated littermates. In fact, they showed similar gait properties to Npc1 ^+/+ mice. Motor Function Analysis

Analysis at eight weeks of age revealed no difference in motor function properties between NpcV ^~ and wild-type (Npc1 ^+/+ ) mice (data not shown).

By nine weeks of age, however, defects in motor coordination had become apparent.

The results of the motor function analysis at nine weeks are shown in Figure 4. Centre rearing, activity, rearing and front to back (FR) count are shown in Figures 4A - 4D, respectively. Active time, mobile time, rearing time and total manual rearing count are shown in Figures 4E - 4H, respectively. Data are presented as mean ± SEM. n=3 for Npc1 ^+/+ untreated, n=2 for Npc1 ^+/+ treated, n=1 for Npc1 ^~ ' ^~ untreated (hence no statistical analysis performed), n=3 for Npc ' ^~ treated. The first bar in each graph shows the motor function properties of wild-type (Npc1 ^+/+ ) mice. The second bar in each graph shows the motor function properties of wild-type (Npc1 ^+/+ ) mice treated with acetyl-DL-leucine. There was no significant difference in motor function properties between these mice and their untreated littermates.

The third bar in each graph shows the motor function properties of an Npc ' ^~ mouse. On the whole, this mouse showed poor motor function compared to Npc1 ^+/+ mice. The mouse spent extremely little time, if any, rearing (panel H), particularly on its hind legs

unsupported (panel A).

The fourth bar in each graph shows the motor function properties of A/pc7 ^~/_ mice treated with acetyl-DL-leucine. These mice demonstrated significantly improved motor function compared to their untreated littermates. In fact, they showed similar motor function properties to Npc1 ^+/+ mice.

Lifespan

It was also observed that treatment of the Npc1-/- mouse with acetyl-DL-leucine (0.1 g/kg from 3 weeks of age) is associated with a statistically significant increase in lifespan (Figure 5). This data further indicates the effect of acetyl-leucine in delaying the onset of the disease.

Conclusion

Where Npc1 ^~ ' ^~ mice had discernible indication of disease that distinguished them from wild-type littermates from 5-6 weeks of age, NpcV ^~ littermates treated with acetyl-DL- leucine from weaning did not display such symptoms until two or more weeks later.

Treatment of NpcV ^~ mice with acetyl-DL-leucine delayed onset and progression of NPC symptoms and showed evidence of neuroprotection.

It is reasonable to expect that, as acetyl-DL-leucine provided general neuroprotection, that the results observed in NPC will also be observed in other neurodegenerative disorders, and neurodegenerative disorders that are associated with defects in lysosomal storage. Example 2

Methods

A fibroblast cell line from an NPC patient was treated for 3 days with N-acetyl-DL-leucine (1 mM) and relative lysosomal volume was quantified via LysoTracker, a fluorescent dye that accumulates in acidic organelles. Increased LysoTracker fluorescence is indicative of an increase in lysosomal size and/or number, and is a hallmark of NPC cells.

In addition, fibroblasts derived from Niemann-Pick A (NPA), Mucolipidosis Type II (MLII), Mucopolysaccharidosis Type NIB (MPS NIB), Aspartylglucosaminuria, Mucolipidosis Type IIIA (MLIIIA), and Mucopolysaccharidosis Type VII (MPS VII) patients were treated with acetyl-DL-Leucine (1 mM) for 6 days and lysosomal volume was quantified via

LysoTracker.

Results

Treatment of fibroblasts derived from an NPC patient of mild clinical severity with 1 mM N- acetyl-DL-leucine was associated with a significant decrease in LysoTracker fluorescence, indicative of reduced lysosomal volume over time (Figure 6A). These findings were replicated in fibroblasts obtained from additional NPC patients of variable clinical severity that were treated with 1 mM N-acetyl-DL-leucine for 72 hours (Figure 6B).

Fibroblasts derived from NPA, and MLII, MPS NIB, Aspartylglucosaminuria, MLIIIA, and MPS VII patients were observed to have elevated LysoTracker fluorescence levels relative to age-matched wild-type controls (Figures 6C-6H). This is indicative of an expanded lysosome occurring as a result of lipid storage compared to fibroblasts from healthy individuals. Treatment with acetyl-leucine was associated with a statistically significant reduction in LysoTracker fluorescence toward control level in both the NPA, and MLII, and MPS NIB fibroblasts relative to untreated NPA, and MLII, and MPS NIB fibroblasts, respectively (Figures 6C-6E), and was associated with a trend in reducing LysoTracker fluorescence toward control level in the aspartylglucosaminuria, MLIIIA, and MPS VII fibroblasts relative to untreated aspartylglucosaminuria, MLIIIA, and MPS VII fibroblasts, respectively (Figures 6F-6H). The reduction in LysoTracker fluorescence was indicative of a decrease in lysosomal volume (Figures 6C-6H and 6D). Data presented in Figures 6A - 6D show the results after 6 days of the treatment for each cell line, respectively with 1 mM acetyl-leucine, with lysosomal volume expressed as fold change relative to untreated wild- type fibroblasts. The asterisks (*/****) indicates a p-values of ( <0.05/0.001) versus untreated disease fibroblasts. Conclusion

N-acetyl-DL-leucine treatment was associated with the rectification of disturbed lysosomal storage by reducing lysosomal volume and thus acetyl-leucine directly corrected a phenotype of these lysosomal storage disorders. These diseases represent different classes of LSDs, and thus these results further support utility of acetyl-leucine's effect against a broad range of lysosomal storage disorders.

Example 3

Sandhoff disease is a disorder which may result from the autosomal recessive inheritance of mutations in the HEXB gene, which encodes the beta-subunit of beta-hexosaminidase. As a result of this, GM2 ganglioside fails to be degraded and accumulates within lysosomes in cells of the periphery and the central nervous system (CNS).

This study made use of a mouse model of Sandhoff disease, the exb ^~ ' ^~ mouse, as descrbed in Jeyakumar et al. (Jeyakumar, M. et al. (1999) Proc. Natl. Acad. Sci. USA 96: 6388-6393).

Wild-type (Hexb ^+/+ ) mice were used as controls. Lifespan

Treatment with acetyl-DL-Leucine was associated with a statistically significant increase in the lifespan of the Sandhoff mouse (Figure 7A). In Figure 7A, acetyl-leucine-treated mice were treated with 0.1 g/kg acetyl-leucine from 3 weeks of age. The asterisks (*) indicates a p-value of <0.05 vs untreated Sandhoff mice. Data is average of n=6 mice per group. Without treatment, the median survival time of Sandhoff mice was 1 12 days. Treatment with acetyl-leucine (0.1 g/kg body weight since 3 weeks of age) increased the median lifespan to 120 days. Motor function

Treatment of Sandhoff mice with acetyl-leucine gave rise to improvements in motor function as indicated by bar crossing and step cycle studies.

Bar crossing test The bar crossing test is a method for assessing motor function in mice in which the mouse is placed hanging from the centre of a horizontal bar by its front limbs. A wild-type mouse with normal motor function will be able to engage its hind limbs and thereby move to one of the platforms at either end of the bar, and in doing so complete the test.

An untreated Sandhoff mouse is able to complete the test up until around 11 weeks of age. After this point motor function and hind-limb mobility/engagement have deteriorated to the point to which the mouse cannot complete the test, and will drop from the bar onto the padded surface below.

Treatment of the Sandhoff mouse model with acetyl-DL-leucine (0.1 g/kg body weight from 3 weeks of age) was associated with improved motor function and hind-limb

mobility/engagement as assessed via the bar-crossing test (Figure 7B). In Figure 7 B, acetyl-leucine treatment of 0.1 g/kg body weight was provided from 3 weeks of age. The acetyl-leucine treated Sandhoff mice retained the ability to complete the test up to 13 weeks of age (inclusive). Data shown is the mean of 6 mice per group. The treated Sandhoff mice retained the ability to complete the test up to 13 weeks of age (inclusive). Step cycle

Step cycle is the length of time taken during locomotion by a limb from the time it leaves the ground until it leaves the ground on the next occasion.

Step cycle time was assessed at 12 weeks of age in untreated and acetyl-leucine treated Sandhoff model mice. Acetyl-leucine treatment constituted 0.1 g/kg body weight acetyl- leucine from 3 weeks of age.

Treatment of the Sandhoff mouse model with acetyl-leucine was associated with significantly faster front step cycle times (p<0.05 vs untreated SH mouse), significantly faster hind step cycle times (p<0.01 vs untreated SH mouse) and significantly faster average step cycle times (p<0.001 vs untreated SH mouse) (Figure 7C). In Figure 7 C, Acetyl-leucine treatment of 0.1 g/kg body weight was provided from 3 weeks of age. Front step cycle refers to the mouse's front limbs, hind step cycle to the mouse's rear limbs, and average step cycle takes into account all of the mouse's limbs. The asterisks (*/**/***) indicate p-values of \<0.05/0.01/0.001 versus untreated Sandhoff mouse. Data shown is mean ± Stdev.

Thus, acetyl-leucine treatment was associated with a faster step cycle in the Sandhoff mouse model, which may indicate improvement in motor function.

Conclusions These studies demonstrate that acetyl-leucine treatment of a mouse model of Sandhoff disease may give rise to improvements in motor function as assessed by two independent experiments, as well as significantly increased lifespan.

Example 4

GM2 gangliosidoses are a group of lysosomal storage disorders arising from defects in β- hexosaminidase activity. The group encompasses Tay-Sachs disease, Sandhoff disease, and the AB variant of Tay-Sachs disease.

Fibroblasts derived from GM2 patients (Tay-Sachs disease, Sandhoff disease, and the AB variant of Tay-Sachs disease) and healthy controls were treated with acetyl-DL-leucine (1 mM for 6 days) prior to extraction and quantification of glycosphingolipid (GSL) levels via high performance liquid chromatography (HPLC).

In the absence of treatment, fibroblasts derived from all 3 varieties of GM2 gangliosidosis demonstrated elevated GSL levels when compared to untreated wild-type controls. In all 3 cases, treatment with acetyl-DL-leucine (1 mM for 6 days) was associated with a reduction in GSL storage. In the case of Tay-Sachs disease, this decrease was statistically significant (p<0.05). In the case of Sandhoff disease and the AB variant of Tay-Sachs, there was a trend towards decreased GSL levels associated with treatment. Data presented in Figures 8A - 8C show the results of the treatment for each cell line, respectively, with GSL levels adjusted for protein content and expressed as fold change relative to levels in untreated wild-type fibroblasts. Example 5 Patient 1

The patient in this case study was a 28 year-old male who was genetically diagnosed with Tay-Sachs disease and who exhibited dysarthrophonia, tremor, ataxia of stance and gait, paraparesis and muscle atrophies. In particular, the patient was not able to stand or walk, could do single steps with strong support, and had distinct postural instability, ocular movement disorder, dysphagia and dysarthria, and mild cognitive function disorder. First symptoms were observed at the age of 16 years.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 15.5/40. In addition, results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): 21.6 s

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 48.3 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 44.9 s MW PATA Word Test: 20

Montreal Cognitive Assessment (MoCA): 18/30

Video of the patient was also recorded for later comparison.

The day following this examination, the patient was started on therapy with acetyl-leucine, at a dose of 3 g per day for the first week, followed by a dose of 5 g per day for the second week onwards.

After one month and four months, respectively, the patient was re-examined while continuing treatment. After one month, the patient had improved fine motor skills and reduced hand tremor, for example while eating or drinking. Walking was not markedly changed. After four months, the patient was in stable condition with slightly improved cognitive function but had deterioration of stance, gait and fine motor function. The patient's SARA scores and results from the patient's SCAFI analyses are shown below compared to baseline. Table 1. Patient Evaluation Parameters

Overall, the patient exhibited an improvement in symptoms following acetyl-leucine treatment.

Patient 2

The patient in this case study was a 32 year-old female who was genetically diagnosed with Tay-Sachs disease and who exhibited ataxia of stance and gait, fine motor impairment, paraparesis of lower extremities, and muscle atrophies. In particular, walking was not possible without support, and the patient suffered from dysphagia and speech disorder, ocular movement disorder, and mild cognitive function disorder. First symptoms were observed at the age of 7 years.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 10.5/40. In addition, results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were: Mean 8-meters Walking Test (8MW): 12.5 s

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 21.5 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 35.5 s

MW PATA Word Test: 18

Montreal Cognitive Assessment (MoCA): 21/30

Video of the patient was also recorded for later comparison.

The day of the examination, the patient was started on therapy with acetyl-leucine at a dose of 3 g per day for the first week, followed by a dose of 5 g per day for the second week onwards.

After one month, the patient was re-examined while continuing treatment and showed increased enunciation, improved postural stability, and enhanced cognitive function. Stance and gait were possible without support. The patient's SARA score and results from the patient's SCAFI analysis are shown below compared to baseline.

Patient 3

The patient in this case study was an 8 year-old male who was genetically diagnosed with Tay-Sachs disease and who had epileptic cramps (tonic-clonic, about 10 seconds, self- limiting) almost every day before falling asleep, ocular movement disorder, anarthria, distinct problems in cognitive function and concentration (neurological examination was not possible), was not able to stand or walk by himself, and was very limited in daily activities (eating, washing or dressing himself was not possible). First symptoms were observed at the age of 9 months.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 36/40, a mRDS score of 18/24, a EQ- 5D-5L visual scale of 50, and a 8MWT of 18.1 (only with strong support).

The patient was started on therapy with acetyl-leucine at a dose of 1.5 g per day for the first week, followed by a dose of 3 g per day for the second week onwards.

After one month, the patient was re-examined while continuing treatment and showed increased fine motor skills (was able to grab small things), increased motivation (tried more often to walk by himself), improved postural stability, gait and stance, and could speak single words. The patient's SARA, mRDS, EQ-5D-5L visual scale, and 8MWT scores are shown below compared to baseline.

Example 6

The patient in this case study was a 13 year-old male who was genetically diagnosed with GM1 Gangliosidosis and who was not able to stand or walk by himself, was very limited in daily activities (eating, washing, dressing himself was not possible), and had ocular movement disorder, anarthria, and distinct problems in cognitive function and

concentration (neurological examination was not possible). First symptoms were observed at the age of 2 years.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 35/40, a mRDS score of 15, and a EQ- 5D-5L visual scale of 50.

The patient was started on therapy with acetyl-leucine at a dose of 1.5 g per day for the first week, followed by a dose of 3 g per day for the second week onwards.

After one month, the patient was re-examined while continuing treatment and showed a stable general condition, increased gait (more fluent), and stable stance in natural position. The patient's SARA, mRDS, and EQ-5D-5L visual scale scores are shown below compared to baseline.

Example 7 Patient 1 The patient in this case study was a 73 year-old male who had previously been diagnosed with amyotrophic lateral sclerosis (ALS).

The patient's symptomatology was characterised by progredient dysarthria (nasal and slurred speech) and weakness of the right dorsiflexor with consequent foot drop over the course of the previous three years.

Clinically, the patient showed bulbar speech, a 3/5 paresis of the right foot-dorsiflexors and big toe-lift, generalised exaggerated reflexes and spastic tone increase of the right lower limb. EMG showed spontaneous activity and cMRT did not show any pathology.

The patient was started on medication with Riluzol around the time of ALS diagnosis. However, the clinical symptomatology remained unchanged.

The patient was then started on therapy with acetyl-DL-leucine, at a dose of 3 gram per day for the first week, then a dose of 5 gram per day for the second week onwards. The results were documented by video.

After 15 days of treatment, a medical examination was conducted in which the patient reported significant improvement of speech. The patient was able to speak more fluently and was able to modulate his voice better compared to pre-medication (which was documented by video).

After a further 20 days, a further medical examination was conducted in which the patient reported further improvement of speech. In addition, the patient reported improvement of gait. The paresis of the right foot-dorsiflexors and consequently the foot drop had improved dramatically and were clinically hardly detectable. In addition, the patient reported an improvement in sleep: falling asleep much quicker, sleeping longer and feeling clearly more rested in the morning.

The patient continued on the treatment for approximately another 30 days. About 7 days after the patient stopped treatment, a medical examination was conducted in which the patient reported no further subjective improvement of either speech or paresis of the right dorsiflexor. Sleep had also deterioriated. After about 1-2 additional weeks off the acetyl- leucine treatment, the patient reported deterioration of speech. The patient resumed treatment at that time and, about two months later, reported stable symptomatology. Compared to the at the time when acetyl-leucine treatment was first initiated, a slight deterioration of speech could be observed.

As the patient had not observed any improvement of speech, the patient asked to stop the medication. Approximately 2-3 weeks later, the patient again reported deterioration of speech after discontinuation of acetyl-DL-leucine treatment. The patient resumed treatment and reported improved symptomatology, in particular speech.

Overall, the patient exhibited an improvement in symptoms following acetyl-leucine treatment.

Patient 2

The patient in this case study was a 74 old male who had been previously diagnosed with ALS.

The patient's symptomatology was characterised by progredient dysarthria (nasal and slurred speech) and concomitant dysphagia, and weakness while walking for over a year, and a paresis of the left upper limb for approximately four months. EMG had shown generalised polyphasic activity and chronic neurogenic impairment in the bulbar, cervical and lumbar segment.

Clinical examination of the patient showed severe dysarthria, hypomotility of the tongue, 2/5-3/5 paresis of the left arm with impairment of fine motor skills, generalised exaggerated reflexes and fasciculations. Medication with Riluzol had been started one month earlier.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then a dose of 5 g per day for the second week onwards.

After approximately 2 months, the patient was re-examined and he reported progredient deterioration of the motor function of the left hand, but a discrete improvement of walking. In addition, swallowing functions have remained stable.

Patient 3 The patient in this case study was a 66 year old male who had been previously diagnosed with ALS.

The patient's symptomatology was characterized by progredient weakness and atrophy of both proximal upper extremities, slight impairment of fine motor skills, and generalized fasciculations and cramps. EMG had shown pathologic spontaneous activity and chronic neurogenic change, MRT of the brain and cervical column did not show any pathology . Medication with Riluzol was started.

About two months later, a clinical examination showed a 3/5 to 4/5 paresis of both shoulders and proximal arms and a slowing of fine motor scills, generalized fasciculations, and normal reflexes. The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then a dose of 5 g per day for the second week onwards.

After one month, the patient did not report improvement of symptomatology, with no improvement of muscle force of upper limbs. Medication with acetyl-DL-leucine was suspended and the patient was asked to report worsening of symptomatology.

Patient 4

The patient in this case study was a 66 year old male who had been diagnosed with ALS. The patient's symptomatology was characterized by progressive weakness and atrophy of both proximal upper extremities, slight impairment of fine motor skills, and generalized fasciculations and cramps. EMG showed pathologic spontaneous activity and chronic neurogenic change. MRT of the brain and cervical column did not show any pathology. Treatment with riluzole was started.

A clinical examination showed a 3/5 to 4/5 paresis of both shoulders and proximal arms, a slowing of fine motor scills, generalized fasciculations, and normal reflexes, and an ALS- FRS score of 44/48.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then a dose of 5 g per day for the second week onwards. After about one month, the patient reported subjective improvement of dysphagia and less hypersalivation. His relatives reported improved and more vital facial expression.

Weakness of limbs was unchanged. Therapy was suspended and, 10 days later, the patient reported worsening of symptomatology, particularly subjective deterioration of dysphagia and hypersalivation. The patient resumed continuous treatment.

The patient was re-evaluated about 8 weeks later and symptomatology remained stable. The patient's ALS-FRS score was 43/48. Compared to symptomatology around the time of diagnosis, there was only a slight progression of weakness of gait and upper limbs.

Example 8 Acetyl-leucine treatment was demonstrated to give rise to improvements in 3 patients who had been diagnosed with multisystemic atrophy cerebellar type (MSA-C).

Patient 1

Patient 1 in this case study was a female in her late 50s who had shown progressive ataxia with speech problems and walking problems for the previous three years. Clinical examination of the patient revealed central cerebellar ocular motor signs, moderate dysarthrophonia, mild limb ataxia, and moderate ataxia of stance and gait. Furthermore, a MRI of the patient showed atrophy of the cerebellum and the brainstem, in particular of the pons and mesencephalon. The patient was accordingly diagnosed as having MSA-C. The patient was started on treatment with acetyl-DL-leucine, at a dose of 5 g per day (2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal).

After one week of treatment the patient already showed a significant improvement in speech.

Patient 2

The patient in this case study was a 77 year-old male who had been diagnosed with MSA- C. The patient's symptomatology was characterised by progressive difficulties of walking and insecure gait with a tendency to fall (the patient fell approximately 10 times a month). The patient exhibited dizziness, hypokinetic-rigid syndrome, saccadic eye movements, dysmetria in the coordination test, and autonomic dysfunction, for example erectile dysfunction, orthostatic hypotension and incomplete bladder emptying over the course of the last four years.

Before treatment was commenced, the patient's symptoms remained unchanged over at least a three-month period.

The patient was started on treatment with acetyl-DL-leucine at a dose of 3 gram per day for the first week, followed by a dose of up to 5 gram per day.

After 3 weeks of treatment, a further examination was carried out. The patient and his wife reported significant improvement of gait: the patient walks more securely and the falls completely stopped. In addition, dizziness experienced by the patient substantially improved. The patient was instructed to stop the medication and after one week the patient reported a deterioration of gait and dizziness. The patient reported feeling more insecure walking, with a strong tendency to fall.

The patient was then instructed to restart the medication, which he continued for a further 40 days and then again stopped. During clinical examination 7 days after stopping the medication, the patient confirmed progressive deterioration of gait and dizziness two days after stopping the treatment, and a very strong tendency to fall 5 days after stopping the treatment. The patient subsequently returned to continuous treatment.

Patient 3 The patient in this case study was a 76 year-old male who had been diagnosed with oligosymptomatic MSA-C.

The patient's symptomatology was characterised by progressive difficulties in walking and insecure gait (without falls), as well as dizziness. Clinically, the patient showed saccadic eye movement and dysmetria in the coordination tests. cMRI showed an atrophy of the mesencephalon, and FDG-PET of the brain showed a reduced metabolism of the striatum and cerebellum. The patient's posturography test results were pathological with a high tendency to fall.

Before treatment was commenced, the patient's clinical symptomatology remained unchanged over at least a one-year period.

Gait analysis was performed, which showed atactic gait, and reduced speed and increased track width compared to the normal range, and fluctuations of gait. The patient was then started on treatment with acetyl-DL-leucine at a dose of 3 gram per day for the first week, followed by a dose of 5 gram per day for the second week onwards.

After one month of treatment, a further examination was carried out. Gait analysis showed an improvement of gait speed, and reductions of track width and gait fluctuations.

Table 5. Gait analysis parameters.

The patient was instructed to stop the medication and he reported progressive deterioration of gait and dizziness approximately two to three weeks after stopping the medication.

The patient subsequently returned to continuous treatment and symptomatology re- improved. Treatment was again suspended and the patient was evaluated three weeks later. The patient reported deterioration of symptoms, especially dizziness. Gait analysis showed an increased gait width comparable to pre-therapy status:

Table 6. Gait analysis parameters.

Example 9

The patient in this case study was a 59 year-old male with progredient personality change characterised by apathy, lethargy and indifference. In addition, the patient showed a mainly left-side hypokinetic-rigid syndrome with impairment of fine motor skills and reduced resonation of left arm. Furthermore, the patient showed generalised bradykinesia and gait disorder with small steps and 2-3 falls per month. The patient also shows slurred speech and cognitive deficits concerning psychomotoric slowing and reduced semantic word fluency. The patient was diagnosed with frontotemporal dementia with parkinsonism and Datscan revealed a reduction of dopamine receptors supporting the diagnosis. FDG-PET of the brain showed a mainly frontal reduced metabolism.

The patient exhibited little improvement during treatment with L-Dopa and Ropinirol. The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 gram per day for one week, then a dose of 5 gram per day for 4 weeks.

After approximately one month of acetyl-leucine treatment, medication was stopped and the patient was re-examined 13 days later.

The patient and his wife and daughter reported a significant improvement of gait under therapy with acetyl-leucine and in addition the patient's falls stopped. The patient also exhibited an improvement of speech, which was less slurred, more comprehensible and subjectively much more controlled. After suspension of treatment the symptoms worsened.

Example 10 The patient in this case study was a 75 year-old male with progressive insecure gait disorder and dizziness leading to backward falls. In addition, the patient presented a mainly left-sided hypokinetic-rigid syndrome with apraxia and alien-limb phenomenon.

The patient was diagnosed with corticobasal syndrome. A Datscan revealed a reduction of dopamine-receptors and an MRI showed an atrophic motorcortex of the right hemisphere supporting the diagnosis.

The patient exhibited no improvement during treatment with L-Dopa.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. Gait analysis was performed before treatment

commenced. After 20 days of acetyl-leucine treatment, the patient was re-examined. An improvement of dizziness symptoms and significant reduction in the frequency of falls was noted. Table 7. Gait analysis parameters.

There was an objective improvement in gait analysis parameters, for example in speed, maximal speed, cadence and reduced double stance (Table 2 and Figure 9).

After 8 weeks of acetyl-leucine treatment, medication was stopped and the patient was reexamined 6 days later.

The patient reported an increase of dizziness symptoms two days after suspension of treatment (the sensation of being drunk).

The patient subsequently returned to continuous treatment. Example 11

Patient 1

The patient in this case study was a 76 year-old female with dizziness, which mainly occurred while walking. No falls were reported. The patient also exhibited gait disorder with small steps and generalised bradykinesia and vertical gaze palsy with impairment of fine motor skills.

The patient was diagnosed with progressive supranuclear palsy. Datscan revealed a reduction of dopamine-receptors and FDG-PET of the brain showed a mainly frontal reduced metabolism, supporting the diagnosis.

The patient exhibited little improvement during treatment with L-Dopa.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for one week, then a dose of 5 g per day for 4 weeks. After 27 days of acetyl-leucine treatment, medication was stopped and the patient was re-examined 60 days later. The patient reported a significant reduction of dizziness and slight improvement of gait under therapy with acetyl-leucine. After suspension of treatment, the symptoms worsened.

The patient was re-examined about two months later and reported a stable

symptomatology of underlying progressive supranuclear palsy; there was no clinical progression. The PSPRS Score remained stable, and the reduction of dizziness was still significant.

Patient 2

The patient in this case study was a 66 year-old female with symmetric hypokinetic-rigid syndrome, gait disorder with insecure and small steps (strong tendency to fall) and vertical gaze palsy with impairment of fine motor skills. The patient was diagnosed with progressive supranuclear palsy. Datscan revealed a reduction of dopamine-receptors and FDG-PET of the brain showed a mainly frontal reduced metabolism, supporting the diagnosis. There was no levodopa response.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. Gait analysis was performed before treatment commenced. After 17 days of treatment, medication was stopped and the patient was reexamined 4 days later. The patient reported no significant improvement of gait or hypokinetic rigid syndrome.

Table 8. Gait analysis parameters.

The patient was reevaluated about two months later and reported no deterioration of symptoms after stopping medication.

Patient 3 The patient in this case study was a 56 year-old male with symmetric hypokinetic-rigid syndrome, insecure and history of falls and vertical gaze palsy with impairment of fine motor skills. The patient was diagnosed with progressive supranuclear palsy. Datscan revealed a reduction of dopamine-receptors and FDG-PET of the brain showed a frontomesial and parietotemporal reduced metabolism, supporting the diagnosis. There was no levodopa response.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. Gait analysis was performed before treatment commenced. After 17 days of treatment, medication was stopped and the patient was reexamined 4 days later. The patient reported no significant improvement of gait or hypokinetic rigid syndrome.

Table 9. Gait analysis parameters.

The patient was reevaluated about two months later and reported no deterioration of symptoms after stopping medication.

Patient 4

The patient in this case study was a 76 year-old male with progredient gait disorder, insecure and small steps (strong tendency to fall), camptocormia, slow and hypometric saccades, blepharospasmus and impairment of fine motor skills. The patient was diagnosed with progressive supranuclear palsy. MRI showed discreet atrophy of the mid brain (Mickey Mouse sign). There was a slight levodopa response.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. Gait analysis was performed before treatment commenced. After three weeks of treatment, medication was stopped and the patient was re-examined. The patient reported gait with increased subjective security and with reduced frequency of falls. Gait analysis showed improvement of gait with increased speed, max. speed, and step cycle length and reduction of track width, double stance and coefficient of variation.

Table 10. Gait analysis parameters.

After three months without medication, the patient reported a progression of hypokinetic- rigid syndrome. Gait worsened, with more frequent falls.

Example 12 Patient 1

The patient in this case study was a 42 year-old male engineer who had suffered from dizziness and postural imbalance for almost one year.

The patient was diagnosed with downbeat nystagmus: the patient was severely impaired by blurred vision (oscillopsia) due to the nystagmus, and experienced difficulties while reading and writing. The patient's visual acuity was: right 0.75, left 0.67, binocular 0.83, and the downbeat nystagmus was documented by video-oculography. The patient also exhibited increased body sway, which was documented by posturography.

Treatment with 4-aminopyridine (Fampyra, 10 mg twice daily) for four weeks did not give rise to any benefit.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day (1 g upon waking, 1 g prior to lunch and 1 g prior to the evening meal) for one week, then a dose of 5 gram per day (2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal). After 10 days, the patient reported significant benefit and that the effect developed slowly. The patient continued with this treatment dosage, and no side-effects resulted. A temporary suspension of the medication led to a considerable deterioration.

The patient was re-examined approximately 14 weeks after starting acetyl-leucine treatment, during which the patient reported to be very happy with the benefit. The patient's reading and writing were much better, because of reduced oscillopsia: the image of the visual surrounding was stable. The patient was able to suppress the nystagmus by visual fixation. In addition, the patient's spatial orientation was improved. Clinical examination by two independent examiners revealed a reduction of the nystagmus and video-oculography showed that the patient could suppress the nystagmus by visual fixation. The patient's visual acuity was: right 0.83, left 1.0, binocular 1.

Posturography demonstrated a reduction of postural sway. Overall, this case study demonstrates improvement in the patient's symptoms for this indication.

Patient 2

The patient in this case study was diagnosed with downbeat nystagmus. The patient showed postural imbalance and dizziness. The patient did not benefit from Fampyra®. The patient began taking acetyl-DL-leucine (3 g/day for the first week; 5 g/day thereafter) and subsequently showed improvement of gait, with the ability to walk much longer distances (one hour), and improved alertness. The patient's downbeat nystagmus also improved (documented by video-oculography). The patient could partially suppress the nystagmus by visual fixation, as evaluated using a target center (dot presented in the center of a display for 30 seconds, Figure 13A) and in complete darkness using goggles covered with special glasses for 45 seconds (Figure 13B). The results (median of slow phase velocity, SPV) were as follows: Target Center— horizontal: -0.02 s, vertical: 2.41 s; Complete Darkness— horizontal: 0.05 7s, vertical: 3.27 7s (Figure 13C). The patient was able to minimize eye movements while fixating, as shown in Figure 13A. Gait analysis showed an increase of self-chosen velocity from 56 to 85 cm/sec and maximal gait velocity from 122 to 155 cm/sec. Medication was then suspended.

About one month after stopping acetyl-DL-leucine treatment, the patient's symptomatology worsened. Gait analysis showed a decrease of self-chosen velocity from 85 to 72 cm/sec and maximal gait velocity from 155 to 113 cm/sec.

Example 13

Patient 1 The patient in this case study was a 70 year-old female with mainly right sided hypokinetic- rigid syndrome and tremor, antecollis, frequent falls, orthostatic dysfunction and urge incontinence.

The patient was diagnosed with with multiple system atrophy Parkinson type (MSA-P). Datscan revealed a mainly left sided reduction of dopamine-receptors and FDG-PET of the brain showed a mainly parieto-occipital reduced metabolism. There was a discreet Levodopa response (100/25mg 3 x daily).

The patient began taking acetyl-DL-leucine (3 g/day for the first week; 5 g/day thereafter). After 3 weeks on acetyl-DL-leucine, the patient was evaluated and reported no significant improvement of gait, reduction of falls or improved hypokinetic rigid-syndrome. Medication was stopped.

6 weeks later the patient did not report deterioration of symptoms after stopping medication.

Patient 2 The patient in this case study was a 78 year-old male diagnosed with multiple system atrophy Parkinson type (MSA-P). The patient's symptomatology was characterized by a progressive hypokinetic-rigid syndrome, orthostatic dysfunction and consecutive dizziness and balance disorder. The patient showed saccadic eye movement and symmetric rigor of both upper limbs. Balancing on an imaginary tightrope was associated with insecureness and loss of balance. FDG-PET of the brain showed a reduced metabolism of both parietal and occipital cortex, suggestive for Lewy-Body-Dementia.

The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. The patient was examined before initiation of treatment and showed the clinical symptomatology described above, with very pronounced insecure gait and dizziness.

After one month of treatment, medication was stopped and the patient was evaluated. The patient reported subjective improvement of dizziness and clinical examination showed improved balancing on an imaginary tightrope, which the patient performed without any difficulties compared to the prior examination. Gait analysis was performed. After one month without medication, the patient reported stable symptomatology. No worsening of dizziness or insecurity of gait was reported. Gait analysis was performed.

After two months without medication, a gait analysis was performed and showed reduction of velocity of gait, reduction of step length and worsening of FGA-Score. The patient reported a worsening of general symptomatology, including progressive weakness of legs and increased insecureness of gait.

Table 11. Gait analysis parameters.

Patient 3

The patient in this case study was a 78 year-old male diagnosed with multiple system atrophy Parkinson type (MSA-P). The patient's symptomatology was characterized by progressive hypokinetic-rigid syndrome, urinary incontinence, incipient cognitive dysfunction, and gait disorder with small steps and 2-3 falls per month. Cognitive deficits were characterized by psychomotoric slowing and intermittent mental confusion. Datscan revealed a reduction of dopamine-receptors, which supported the diagnosis. FDG-PET of the brain showed a mainly striatal reduced metabolism. Levodopa therapy was suspended due to side effects. The patient was started on treatment with acetyl-DL-leucine, at a dose of 3 g per day for the first week, then 5 g per day. The patient evaluated after one month on acetyl-DL- leucine. The patient's wife reported a significant improvement of cognitive function.

Episodes of mental confusion completely disappeared. The patient's cognitive structure seemed much clearer and straighter. There was no improvement of gait function. The patient's wife supported continuing the medication.

Example 14

The patient in this case study was a 45-year-old male diagnosed with spinocerebellar ataxia 28 (SCA 28). Genetic testing showed a known pathogenic variant in AFG3L2. The patient's symptomatology was characterized by progressive cerebellar syndrome since the age of 30, characterized by slurred speech, unstable gait, balance disorder and dizziness. The patient's father and grandmother suffered from a similar symptomatology. The patient showed saccadic eye movements and dysmetria in the coordination tests, ataxic gait, slurred speech, exaggerated reflexes of the lower limbs, spasticity of the lower limbs and a positive Babinski sign on the left. cMRI showed a marked atrophy of the cerebellum.

The patient was started on treatment with acetyl-DL-leucine at a dose of 5 g per day. A gait analysis was performed before treatment commenced. After about one month of treatment, medication was stopped and the patient was evaluated. The patient reported an improvement of the symptomatology, in particular reduced dizziness (almost vanished), and a more stable gait. The patient reported that he no longer walked like a robot and could climb the stairs without using the banisters. A gait analysis was performed, which showed an improvement of parameters.

Table 12. Gait analysis parameters. Before After treatment Standard values (±

treatment for one month SD)

Self-chosen speed (cm/

101 118 126.61 (21.43) sec)

Maximum speed (cm/ sec) 188 201 182.94 (25.37)

Cadence (steps/minute) 100 105 1 15.52 (9.36)

Track width (cm) 14.5 11.7 9.43 (2.27)

Step cycle length (cm) 122 135 131.55 (17.98)

Double stance (%) 24.9 23.8 18.76 (3.46)

Coefficient of variation

4.1 2.1 1.88 (0.79)

(temporal)

Functional Gait

24/30 23/30 28.9 (1.5)

Assessment

Example 15 Patients 1 & 2

The patients in this case study were 2 female siblings, 24 (Patient 1) and 19 (Patient 2) years old, respectively. The patients suffer from ataxia telangiectasia.

Patient 1 showed delayed developmental milestones. The patient did not walk until 2 years of age and had progression of cerebellar ataxia signs and symptoms, seizures, together with generalized, distal pronounced hypertonia and telangiectasias on the eyes, ears, and chest. Diagnosis was established at the age of 9 years. Patient 1 's ocular motor function showed downbeat-nystagmus with gaze straight-ahead and in the gaze to the left greater than right, gaze-holding nystagmus upward, vertical and horizontal saccadic smooth pursuit, and hypometric saccades horizontally and vertically, with restricted motility upward.

Before treatment was commenced, examination of Patient 1 indicated a Scale for

Assessment and Rating of Ataxia (SARA) score of 22/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): 21.8 s

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 90.2 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 125.8 s

MW PATA Word Test: 12.5

Visual analog scale (as evaluated by the patient): 99

Results from video-oculography were:

Table 13. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus

Centrum 0.54 6.9

Vpravo -1.16 6.2

Vl'avo 12.2 12.6

Nadol -0.14 6.9

Nahor -0.39 5.95

Patient 1 began treatment with acetyl-DL-leucine (5 g/day) following examination. After one month of treatment, the patient was re-evaluated. Caregivers reported an

improvement of speech and gait. The patient herself did not perceive any change.

Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 15.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): 18.5 s MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 77.9 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 101.3 s MW PATA Word Test: 13

Visual analog scale (as evaluated by the patient): 85

Results from video-oculography were:

Table 14. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus

Center 0.4 4.77

Right -0.95 4.83

Left 8.2 8.85

Down -0.44 5.29

Up 0.72 2.67

Patient 1's SARA and SCAFI subsets improved after treatment, and video-oculography showed significant improvement of fixation stability and decrease of intensity of downbeat- nystagmus.

Patient 2 showed delayed developmental milestones, seizure at the age of 1 , generalized hypotonia, contractures of low extremities with pes equinovarus bilaterally, areflexia, acute lymphoblastic leukemia at the age of 3 years, slightly enlarged spleen, hypercholesterolemia, hypochromatic microcytic anemia, pigmental naevi, and vitiligo. First symptoms were noticed by the patient's parents at the age of 15 months. Patient 2's ocular motor function showed square wave jerks, gaze-holding nystagmus left greater than right with vertical component, downbeat-nystagmus, saccadic smooth pursuit, vertical gaze palsy upward greater than downward, and impaired convergence.

Before treatment was commenced, examination of Patient 2 indicated a Scale for

Assessment and Rating of Ataxia (SARA) score of 28.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform without support MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 300 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 299.2 s

MW PATA Word Test: 13.5

Visual analog scale (as evaluated by the patient): 45

Results from video-oculography were: Table 15. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus

Center -2 6.18

Right -3.97 7.6

Left -0.24 9.49

Down -2.86 5.58

Up -1.11 4.97 Patient 2 began treatment with acetyl-DL-leucine (5 g/day) following examination. After one month of treatment, the patient was re-evaluated. Caregivers reported an

improvement of fine motor function, hand tremor, and speech. The patient herself did not perceive any benefit. Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 23.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform without support MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 300 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 300 s MW PATA Word Test: 14

Visual analog scale (as evaluated by the patient): 80

Results from video-oculography were:

Table 16. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus

Center -1.45 5.6

Right -3.45 6.56

Left 3.58 7

Down -2.5 4.69

Up -0.51 3.15

Video-oculography showed improvement of fixation stability and significant improvement of downbeat-nystagmus intensity in Patient 2.

Patient 3 The patient in this case study was a 19 year old female suffering from ataxia telangiectasia from early childhood, having:

-Delayed motor development, cerebellar ataxia signs and symptoms, pronounced axial hypotonia with acral hypertonia, severe contractures of feet with orthopedic deformities pes equinus et transversoplanus bilaterally and was thus confined to wheelchair, dysdiadochokinesis, and areflexia of low extremities with decreased proprioceptive perception; and

-Non-Hodgkin lymphoma, polymorphism MTHFR (C677T), lymphangioma of the lower lip, cholecystolithiasis, dilated cardiomyopathy, pigmental naevi, thoraco-lumbar

kyphoscoliosis, and scleral teleangiectasias on both eyes.

The patient's ocular motor function showed gaze-holding nystagmus to the right and to the left, saccadic eye movements, slow saccades to all directions, especially horizontally, pathological vestibulo-ocular reflex with corrective catch-up saccades, and pathological visual-fixation suppression of the vestibulo-ocular reflex. Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 23/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 150 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 161.6 s

MW PATA Word Test: 14

Visual analog scale (as evaluated by the patient): 80

Results from video-oculography were: Table 17. Video-oculography parameters. Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus [ s]

Center 3 -1.5

Right -0.4 -1

Left 7.3 2.5

Down 2.4 -0.2

The patient began treatment with acetyl-DL-leucine (5 g/day) about six months after the examination. After slightly over 7 months of treatment, the patient was re-evaluated. Caregivers and patient reported general improvement of well-being, without clearer specification. Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 21.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 124.5s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 147.5 s MW PATA Word Test: 10

Visual analog scale (as evaluated by the patient): 80 Results from video-oculography were: Table 18. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus [ s]

Center -0.1 0.4

Right -4.2 1.7

Left 1.7 0.1

Down -0.6 1.2

The patient showed slight improvement of SARA and SCAFI subset 9HPT, and significant improvement of fixation stability and decrease of intensity of gaze-holding nystagmus at all positions.

Patient 4

The patient in this case study was a 15 year-old female suffering from ataxia telangiectasia from 4-years of age. From 7-years of age, the patient showed severe cerebellar ataxia signs and symptoms, fine motor impairment, muscular hypotonia with areflexia, muscular atrophy, and plantar flexion with discrete contractures. The patient was confined to a wheelchair, but was able to walk with constant support. The patient had severe hemolytic anemia, hypogammaglobulinemia, telangiectasias on the scleras and chest, Secondary Cushing syndrome due to corticosteroid intake, and was suspected of having CNS Non- Hodgkin lymphoma.

The patient's ocular motor function showed slow deviation of the eyes upward, left beating nystagmus in the central position, gaze-holding nystagmus in all directions, horizontally with downbeating component, startle with sudden head movement.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 23.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 124.5 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 52.3 s MW PATA Word Test: 14

Visual analog scale (as evaluated by the patient): 70 Results from video-oculography were:

Table 19. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus [ s]

Right 3.7 -0.1

Left -6 0.6

Down 5.7 2.7

The patient began treatment with acetyl-DL-leucine (5 g/day) following the examination. After slightly over 1 month of treatment, the patient was re-evaluated. The patient and her mother reported improvement in handwriting, especially due to decreased hand tremor and fine motor function. The patient also reported that drinking was easier and no longer needed a straw. Family members described improvement of gait, with increased stability and needing less support. Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 18.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to perform

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 93.5 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 101.7 s MW PATA Word Test: 15.5

Visual analog scale (as evaluated by the patient): 70

Results from video-oculography were:

Table 20. Video-oculography parameters.

Slow phase velocity of the gaze- Horizontal Vertical

holding nystagmus [ s]

Center -0.2 4.8

Right -1 0.3

Left -0.8 1.9

Down -0.7 -2.3

The patient showed improvement of SARA and SCAFI subset 9HPT of the dominant hand. Video-oculography showed general improvement of fixation stability and decrease of intensity of spontaneous and gaze-holding nystagmus at all positions.

Patient 5

The patient in this case study was a 10 year-old boy suffering from ataxia telangiectasia from his early childhood, having:

-Delayed psychomotor development, instable walking at 14 months with increased incidence of falls, severe cerebellar ataxia signs and symptoms, dysarthria and dyslalia, fine motor impairment, infrequent head tremor, slow psychomotor tempo, hypotonia with muscular atrophy and hyporeflexia, anteflexia of the head with kyphosis in the thoracal area, pedes transversoplani, scapullae allatae, parasomnia with pavor nocturnus, and autism; and -Significant immunosuppression, telangiectasias on the soft palate, scleras, incontinence, and asthenic habitus.

The patient was confined to a wheelchair but was able to perform a few steps with strong constant support. The patient's ocular motor function showed oculomotor apraxia with pronounced head anteflexia, head and eye movement "en bloc" when looking to the right and left, vertical gaze palsy with slow vertical saccades and saccadic smooth pursuit, slow horizontal saccades to the left, saccade palsy to the right, restricted eye motility, especially vertically, and fixation instability in all positions.

Before treatment was commenced, examination of the patient indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 24.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to walk without constant support

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 102.7 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 1 16.8 s MW PATA Word Test: 6

Visual analog scale (as evaluated by the patient): 90

Results from video-oculography were:

Slow-phase velocity (SPV) of fixation and gaze-holding nystagmus, [°/s] Table 21. Video-oculography parameters.

Horizontal Vertical

Center 0.96 1.53

Right 0.21 2

Left 2.1 3.64

Down 0.71 3.91

Up 0.31 1.69 The patient began treatment with acetyl-DL-leucine (5 g/day) following examination. After about 1 month of treatment, the patient was re-evaluated. The patient's mother described a significant improvement of stability of the gait; prior to the therapy, he was constantly falling backward and had to be partially "transported". On medication, he was able to walk with only holding the caregiver ^' s hand.

Fine motor function, the intensity of hand tremor, and body holding improved.

Improvement of fine motor function was reflected in daily activities, such as eating and drinking independently. The patient gained 1.5 kg and had a better appetite. Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 20.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): not able to walk without support

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 103.6 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 88.8 s MW PATA Word Test: 7.5

Visual analog scale (as evaluated by the patient): 80

Results from video-oculography were:

Slow-phase velocity (SPV) of fixation and gaze-holding nystagmus, [°/s] Table 22. Video-oculography parameters.

Horizontal Vertical

Center 0.79 3.54

Right 1.17 2.36

Left 1.22 2.53

Down 0.62 1.08

Up 0.33 1.71 After almost 7 months of treatment, the patient was again re-evaluated. The patient's mother described significantly more stable gait; this finding remained constant from the first evaluation after treatment. The patient had improved concentration and speech. The patient could stand up on his own and was generally more independent with daily activities. The patient gained another 3 kg with improved appetite and showed improved strength.

Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 17.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): 15.3 s (holding of the hand)

MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 92.4 s

MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 98.3 s

MW PATA Word Test: 11 Visual analog scale (as evaluated by the patient): 100

The patient was re-evaluated after slightly over a year of treatment and showed improved social interaction, activity, and agility. The patient's parents reported improvement of incontinence. The patient developed a repeatedly occuring frontal localized pain with vomiting in the morning. Based on family history, it was suspected that the localized pain may be due to infantile migraine.

Examination indicated a Scale for Assessment and Rating of Ataxia (SARA) score of 16.5/40. Results from the patient's Spinocerebellar Ataxia Functional Index (SCAFI) analysis were:

Mean 8-meters Walking Test (8MW): 13.9 s (able to walk by himself, mother held hand) MW 9-Hole Pegboard Test Dominant (9HPTD) (right): 95.6 s MW 9-Hole Pegboard Test Non-Dominant (9HPTND): 127.6 s MW PATA Word Test: 14.5

Visual analog scale (as evaluated by the patient): 95

On treatment with acetyl-DL-leucine, the patient showed improved SARA and SCAFI subtests, increased quality of life, generally improved fixation stability and decrease of intensity of spontaneous and gaze-holding nystagmus, especially in the vertical plane (after 1 month).

Patient 6

The patient in this case study was a 10 year-old female suffering from ataxia telangiectasia who had ataxic gait and stance, fine motor function disorder with hand tremor, dysphagia and speech disorder, ocular movement disorder, and problems with cognitive function and concentration. First symptoms were observed at the age of one year.

After baseline examination, the patient started acetyl-DL-leucine treatment at 1.5 g/day for the first week and at 3 g/day for the second week onwards. The patient was evaluated after one month and six months of treatment, respectively. After one month of treatment, the patient showed increased fine motor skills with reduced hand tremor, improved postural stability and gait, increased enunciation, and increased self-confidence. After six months of treatment, the patient had stable general conditions, stable gait and stance, and improved handwriting. The patient, however, was suffering from anxiety, which would be expected to negatively influence the response. The patient's SARA and SCAFI scores at each evaluation are shown below.

Table 23. Patient Evaluation parameters.

Example 16

The patient in this case study was a female in her early 60s who was genetically diagnosed with Spinocerebellar Ataxia (SCA) 1. Before treatment, the patient had severe problems with speaking and swallowing, tremor of both arms, spasticity and moderate ataxia of stance and gait. The patient also had problems sleeping.

Three weeks on medication with acetyl-DL-leucine (5 g/day), all symptoms significantly improved, as further demonstrated by clinical examination, including spasticity and impairment of ocular motor function.

Three months later the medication was stopped. After two weeks, the intensity of the signs and symptoms were the same as before therapy. Treatment was started again, and the patient has remained, and continues, on the treatment after over two years, on the same dosage without any side-effects. The patient's daughter reported considerable progression of the disease over time with a persisting symptomatic effect, yet observed, anecdotally, that there was long-term symptomatic efficacy from treatment.

Example 17 The patient in this case study was a 70 year-old female with insecure gait and frequent falls, visual hallucinations at night, REM-sleep disorder. The patient had symmetric hypokinetic-rigid syndrome with impairment of fine motor skills and fluctuations in attention and awareness. The patient was diagnosed with Lewy Body dementia. FDG-PET of the brain showed a synaptic dysfunction in the parietal and occipital lobe and DATscan showed a

degeneration of presynaptic dopamine transporter, supporting the diagnosis. Treatment with Levodopa 100 mg 4 x daily and Quetiapin 25mg at night improved the

symptomatology. The patient started taking acetyl-leucine (3 g/day for one week; 5 g/day thereafter) and was evaluated after four weeks. The patient reported increased fatigue and a deterioration of balance and speech. Medication was reduced to 3 g/day, and the patient was instructed to stop medication about two weeks later.

The patient was re-evaluated about one month after ceasing medication and did not report improvement of symptomatology with the decreased dose and no deterioration of symptoms after stopping medication.

Table 24. Gait parameters.

Example 18

In this case study, four patients (male siblings) suffered from, and were later diagnosed with, ataxia with oculomotor apraxia type 4. The older three siblings were 12, 11 , and 10 years of age, respectively, at the time of disease onset. Prior to commencing treatment with acetyl-DL-leucine, by the age of 15/16 years, the three older siblings walked with an expedient, as reported by the patients' mother. The older siblings began treatment with acetyl-leucine at 25, 23, and 19 years of age, respectively, and have been on the treatment for approximately four years. No long-term clinical data is available for these three patients.

The youngest sibling was 11 years old at the time of onset. He began treatment with acetyl-DL-leucine at the age of 13. While on treatment, the youngest sibling did not walk with an expedient until nearly 18 years of age, as reported by the patient's mother. The patient's mother also reported that the youngest sibling had improved fine motor skills and improved speech at each age compared to his older siblings. No long-term clinical data is available for the youngest sibling.

Example 19

An NPC patient's severity may be quantified by assigning a clinical severity score (CSS), which assesses various parameters of the disease and gives each parameter a score out of 5 (higher score = greater severity). See Yanjanin et al., "Linear Clinical Progression,

Independent of Age of Onset, in Niemann-Pick Disease, Type C," Am J Med Genet Part B 153B: 132-140. In an untreated patient, one can typically predict how the CSS will change over time in an individual, as disease progression appears to be linear. For example, if Patient A moves from a CSS of 8 to a CSS of 12 between month 0 and month 12, it can be predicted that by month 36, the patient will have a CSS of 20. The annual severity increment score (ASIS) quantities the annual rate of change in the CSS, calculated by dividing the CSS of a patient by the patient's age. For example, if untreated Patient B had a CSS of 8 at two years of age, the patient's ASIS would be 4. Each year, the patient would be expected to progress by 4 CSS points, such that at 4 years of age, the patient's CSS would be 16. If therapeutic intervention slowed or arrested disease progression, one would expect the patient to have a smaller ASIS score after such therapy than at baseline.

Ten NPC patients were administered acetyl-leucine at 4.5 g/day over long durations. A CSS was determined at baseline, and at various time points, for eye movement, ambulation, speech, swallow, fine motor skills, cognition, memory, and seizures. An overall CSS was calculated at baseline and at each such time point by adding the individual CSS values for each parameter (eye movement, ambulation, etc.). The number of days post-initiation of therapy at which CSS was assessed was different for each patient, as shown in Table 25.

Table 25. Days post-initiation of acetyl-leucine administration at which CSS was assessed.

Tables 26-34 below show each CSS for overall, eye movement, ambulation, speech, swallow, fine motor skills, cognition, memory, and seizures, respectively.

Table 26. CSS overall.

Table 27. CSS eye movement.

Table 28. CSS ambulation.

Table 29. CSS speech.

Table 30. CSS swallow.

Table 31. CSS fine motor skills.

Table 32. CSS cognition.

Table 33. CSS memory.

Table 34. CSS seizures.

The ASIS at baseline and each time point was calculated using each patient's CSS and age at the time of assessment. The overall ASIS for each patient at each time point is shown below in Table 35.

Table 35. ASIS overall.

As shown in Table 26 and Figure 10A, none of the ten patients showed an overall increase in CSS over the course of the experiment. Patient 6 showed an increased CSS between baseline and time point 2, but returned to baseline by time point 3 and remained there at time point 4. Four of the ten patients (Patients 2, 5, 6, and 7) had a constant CSS over the course of the experiment, indicating that the disease did not progress in these individuals. Six of the ten patients (Patients 1 , 3, 4, 8, 9, and 10) showed a reduction in CSS over the course of the experiment, indicating that the disease did not progress and actually became less severe. Improvements were seen in different subscores: Patient 1 : ambulation;

Patient 3: fine motor skills; Patient 4: ambulation and speech; Patient 8: eye movement and fine motor skills; Patient 9: memory; Patient 10: cognition. Data presented in Figures 11A-1 1J show the CSS subscores for each patient, respectively, in the form of a bar graph.

As shown in Table 35 and Figures 10B, all ten patients showed a reduction in ASIS during treatment relative to ASIS at baseline. In Patients 2, 5, 6, and 7, CSS remained the same while age increased, resulting in a small reduction in ASIS. In Patients 1 , 3, 4, 8, 9, and 10, the reduction in ASIS was larger due to CSS decreasing while age increased.

Example 20

The Niemann-Pick Disease Type C (NPC) mouse model shares a number of pathological features with Alzheimer's disease (AD) as described herein. Wild type NPC1 ^"A mice were treated with acetyl-dl-leucine (0.1 g/kg body weight daily) from 3 weeks of age. Mice were sacrificed at 8 weeks of age. Levels of amyloid precursor protein C-terminal fragments (APP-CTFs) were evaluated relative to total amyloid precursor protein (APP) levels in the cerebellum for wild type, untreated wild type NPC1 ^"A mice, and AL-treated wild type NPC1 ^" '- mice. Levels of microtubule-associated protein 1 A/1 B-light chain 3- phosphatidylethanolamine conjugate (LC3-II) were also evaluated relative to levels of tubulin loading control for wild type, untreated wild type NPC1 ^"A mice, and AL-treated wild type NPC1 ^"A mice.

The APP-CTF data is shown in Figure 12A. The data replicated the previously noted accumulation of APP-CTFs in the NPC1 mouse brain. Treatment with acetyl-dl-leucine was associated with lowering of APP-CTFs.

The LC3-II data is shown in Figure 12B. The data replicated the previously noted accumulation of LC3-II in the NPC1 mouse brain. Treatment with acetyl-dl-leucine was associated with a lowering of LC3-II, indicative of a partial restoration of autophagic flux. Conclusion

Acetyl-leucine treatment was associated with an improvement in AD pathology in the NPC1 mouse brain.

Example 21

NPC Chinese Hamster Ovary (CHO) cells were treated in vitro for 72 hours with 1 mM of acetyl-DL-leucine, acetyl-L-leucine, acetyl-D-leucine, DL-leucine, L-leucine, and D-leucine, respectively. Relative lysosomal volume was quantified via LysoTracker.

The NPC CHO cells were observed to have elevated LysoTracker fluorescence levels relative to wild-type controls, which is indicative of increased lysosomal volume of the diseased phenotype.

Treatment of the NPC CHO cells with each of acetyl-DL-leucine, acetyl-L-leucine, acetyl- D-leucine, DL-leucine, L-leucine, and D-leucine significantly reduced lysosomal volume in the cells. Data presented in Figure 14 show the results for each treatment, with lysosomal volume expressed as fold change relative to untreated wild-type fibroblasts. The asterisks (**) indicate a p-value of <0.01 versus untreated NPC1-null.

The data shows that leucine and acetyl-leucine demonstrated similar activity in vitro and were both associated with the rectification of disturbed lysosomal storage by reducing lysosomal volume and thus directly corrected a phenotype of lysosomal storage disorders.

Example 22 Subject The subject is a 90-year-old male, and a retired physician with no signs of dementia. He has experienced progressive postural imbalance for five years with no extrapyramidal or cerebellar signs. He has experienced incomplete arousal wakefulness over the past two years but has normal sleep patterns. He had polio in his twenties and has aspects of post- polio syndrome, including partial vocal cord paralysis, muscle weakness and spinal misalignment. He leads an independent active life, reads prolifically and uses a laptop computer to communicate with family. His only medication was glaucoma eye drops at the time of this study.

Initial Treatment Treatment Protocol

Treatment with acetyl-DL-leucine (Tanganil ^® ) was started because the patient was suffering from imbalance and gait disorder. He initiated a one-month course comprising nine 500 mg tablets taken three times a day (TID) with meals, i.e., a total daily dosage of 4.5 g. Measurement of Mobility

The ability of the subject to move was measured in a home setting "get up and go test". This test involved the subject rising unaided from his chair and walking the length of his living area to his kitchen. This was timed over seven consecutive days prior to treatment, and over the next seven consecutive days once treatment with Tanganil ^® had started. Results

By 7-10 days of treatment the subject was more confident walking due to improved balance. In a home setting "get up and go test" the average time taken for the subject to rise unaided from his chair and walk the length of his living area to his kitchen, prior to Tanganil ^® treatment, was 40 ± 3 seconds. The average time taken for this once treatment had started was 30 ± 2 seconds. The subject was consistently 25% faster than pre- treatment. He had been struggling to get in and out of bed and that resolved at the same time. After 2-3 weeks of treatment the subject suddenly described being fully alert on waking and that his mind had cleared. His family noticed a significant improvement in his cognitive function, spatial awareness and general demeanor. He was able to navigate his environment without any of the confusion that had been evident prior to treatment. For example, his house contains numerous doors and, prior to treatment, he often had to stop and think twice about which door to open in order to access a certain room. After treatment this diminished, which was indicative of, inter alia, improved memory.

After one month the subject ceased taking acetyl-DL-leucine. His balance remained good for two weeks then deteriorated, whereas his cognition gradually declined to his pre- treatment status over one month. The "get up and go" test was also similar to his pre- treatment performance level.

Second Treatment

Treatment Protocol

The same subject then initiated another month of treatment, i.e. a further one-month course comprising nine 500 mg capsules taken TID with meals (total daily dosage of 4.5 g).

Results

The improvements the subject had noticed in the first month of treatment rapidly returned. Further Treatment Treatment Protocol

The subject now remains on acetyl-DL-leucine (Tanganil ^® ) at a dose of 4.5 g per day. Results

The improvements the subject had noticed in the first and second months of treatment have continued. The confusion that was evident prior to treatment is now entirely absent. He has experienced no side effects over eighteen months.

Conclusions The subject and his family agree that the acetyl-DL-leucine treatment has resulted in significant benefit on multiple neurological systems, in particular mobility and cognitive function, greatly improving his quality of life.

Example 23

The subject is a 75 year old male patient with balance disorder/senile gait disorder and impaired spatial orientation (non-vertiginous dizziness) leading to backward falls. In addition, the subject presents a very discreet symmetric hypokinetic-rigid syndrome. The subject was diagnosed as having a balance disorder in 2016. Datscan was borderline pathological (i.e. reduction in dopamine receptors indicating possible Parkinson's

Disease), however no improvement was observed during treatment with L-Dopa. An MRI on the subject showed unspecific white matter lesions and a slight atrophy of the right motocortex.

Day 0: the patient was started on a treatment regimen of acetyl-DL-leucine 3 gram per day for the first week, followed by 5 gram per day.

Day 14: The subject was subsequently re-evaluated. An improvement of dizziness symptoms was found along with a significant reduction in the frequency of falls. No change of hypokinetic-rigid syndrome was reported. Day 56: treatment was suspended.

Day 62: The subject was subsequently re-evaluated. The patient reported an increase of dizziness symptoms two days after suspension of treatment (noting the sensation of being drunk).

The study is continuing, with the subject returning to continuous treatment.

Example 24 An 86 year-old male patient was diagnosed with a mild slowly progressive postural imbalance and gait disorder five years earlier. This was described as feeling like a sailor on a ship when walking. From time to time the subject had to use a cane. The subject had no symptoms while sitting or lying. The subject also suffers from atrial fibrillation, and has bilateral hip prostheses.

Clinical examination of the subject revealed slowness of walking with increased body sway. There was evidence for a mild polyneuropathy. There was no evidence for vestibular, ocular motor or cerebellar dysfunction.

Laboratory tests of the vestibular system were normal. Posturography showed increased body sway. Gait analysis revealed small steps and reduced gait velocity.

MRI of the brain was normal.

The patient was treated with Tanganil ^® 500 mg in 3 separate doses throughout the day - 1 g upon waking, 1 g prior to lunch and 1 g prior to the evening meal for one week, followed by 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal.

Feedback by the subject's spouse 22 days after beginning treatment with acetyl-leucine indicated a significant reduction of dizziness and imbalance, and significant improvement of gait. Improvement was reported to have begun in the second week of treatment.

Medication was well tolerated. Further tests have not yet been possible due to the subject experiencing an unrelated illness (flu), but treatment is continuing.

Conclusion

Improvement of gait, reduction of dizziness and imbalance was reported by the spouse and the patient.

Example 25 An 89 year-old male patient presented with gait problems and postural imbalance for three years. There were no symptoms while sitting or lying. The course of the symptoms was slowly progressive. The patient had bilateral hearing problems, but otherwise the patient history was unremarkable.

Clinical examination of the patient revealed slowness of walking with increased body sway while standing with the eyes closed. There was no evidence for vestibular, ocular motor or cerebellar dysfunction.

Laboratory tests of the vestibular system (using video head impulse test, caloric irrigation, vestibular evoked myogenic potentials) were normal.

Video of the patient's gait was taken and the gait was quantitatively analysed (results are shown in Table 36).

An MRI of the patient's brain showed a mild subcortical vascular encephalopathy.

The patient was then treated with Tanganil ^® (500 mg) in 3 separate doses throughout the day - 1 g upon waking, 1 g prior to lunch and 1 g prior to the evening meal for one week, followed by 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal.

In a follow-up 3 weeks after beginning acetyl-leucine treatment the patient and his daughter reported that his gait and imbalance was significantly improved. He could get up much easier and more quickly. He also reported climbing stair cases is much easier. Video analysis shows that the patient is now even able to run. The medication was very well tolerated.

Conclusion

Improvement of gait, reduction of dizziness and imbalance during treatment with Tanganil ^® was reported by the patient and his daughter and further documented by gait analysis and video. The medication was also well tolerated.

The results of quantitative gait analysis before and after treatment are: Table 36

In summary, with acetyl-leucine treatment there was:

an increase of self-chosen gait velocity from 88 to 96 cm/sec; an increase of maximal gait velocity from 141 to 157 cm/sec; and an increase of so-called cadence (steps per minute) from 92 to 100. Overall, there was a significant improvement documented by these quantitative measures.

Example 26

A 77 year-old patient experienced progressive gait disorder with small steps and problems with the initiation of gait for more than five years. MRI showed a subcortical vascular encephalopathy (due to arterial hypertension for many years). Datscan revealed a slight reduction of dopamine-receptors. No improvement was observed during treatment with L- Dopa.

Day 0: the patient reported four falls over the previous three months and the patient's spouse reported mild cognitive impairment in the patient. The diagnosis was confirmed with severe reduction of gait velocity and impaired initiation of gait.

Quantitative gait analysis with the "gait-rite" showed a significant reduction of maximal gait velocity (84 cm/sec) and self-chosen gait velocity (55 cm/sec).

The patient was treated with 3 gram per day of acetyl-DL-leucine for two weeks with a considerable improvement of gait reported by the patient and his spouse.

Then medication was stopped with a worsening of symptoms.

Day 28: Re-evaluation revealed an impairment of gait which was documented by video.

Treatment with 3 gram per day of acetyl-DL-leucine was started again.

Day 42: In a further re-evaluation the subject's spouse reported a dramatic improvement with impact on functioning and quality of living. It was reported by the spouse that the subject's gait was even better than two years ago. No further falls were reported.

Clinical examination revealed significant improvement of gait and balance, the patient was now even able to run (documented by video). Quantitative gait analysis showed an increase of maximal gait velocity from 84 cm/sec to 130 cm/sec (running not quantified) and self-chosen gait velocity from 55 cm/sec to 62 cm/sec.

The subject is now undergoing continuous treatment with further follow-up examinations planned.

Example 27

A 59 year-old male patient was diagnosed with a postural imbalance with occasional falls and stumbles (at a frequency of 2-3 per month). His main complaints were experiencing problems going upstairs and downstairs, and problems walking on uneven ground. The subject reported no tendency to fall in a specific direction. The patient has also complained about a slow progressive cognitive decline, especially in terms of short memory and cognitive flexibility. His family members have noticed perseverations and occasional diffuseness in communication with him. Regarding his comorbidities, he was previously diagnosed with insulin-dependent diabetes mellitus, and with thyroxine-substituted hypothyreosis.

The patient was examined clinically by means of the following clinical assessments:

maximal distance to walk; timed Up and Go test; Scale for the Assessment and Rating of Ataxia (SARA). The patient was also examined by means of posturography after 1 month of the therapy with Tanganil ^® 500 mg (2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal). Medication was taken 30 minutes prior to the meal, or at least 2 hours after the meal.

Baseline (prior to commencement of treatment): Maximal distance to walk until the patient could not walk anymore because of fatigue was 1 km. The stance up-and-go test yielded 25.4 sec. SARA yielded 6.5/40. Clinical examination revealed accentuated postural imbalance, with intentional tremor and dysmetria bilaterally. Stance with feet together was possible with increased omnidirectional sway, which was especially pronounced in the dorsoventral and anteroposterior axes. Tandem stance and gait was not possible to perform due to an increased fall risk. Mean timed 8-meter-walking test was 6.5 sec. The tune-fork examination showed a decreased proprioception on the medial malleolus bilaterally.

During treatment with Tanganil ^® (2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal) for 1-month, the following assessments were made:

Objective Measurements: Maximal distance to walk increased to 1.5 km. The stance up- and-go test on medication yielded 21.2 sec. SARA yielded 2/40. The sway previously experienced became visibly calmer. Stance with feet together, as well as tandem stance and gait was possible with increased omnidirectional sway. Mean timed 8-meter-walking test yielded 4.4 sec.

Subjective Measurements: The patient had more energy, was more agile and interactive, especially after the morning dosage. Since the patient was keen on doing DIY in his house and garden, he described that he had more drive to do these activities, was much quicker and more efficient in his daily routine. His family members noticed that he is more coherent in his communication and his executive function improved as well. He was subjectively more postural stable, both when walking and going upstairs and downstairs. He did not have to hold the side rails in order to stabilise himself. Moreover, he did not record any falls during the therapy period of 1 month.

Side effects: Sleepiness was observed under the 2 g/1.5 g/1.5 g per day dosage regimen. The dosage was reduced to 1 g upon waking, 1 g prior to lunch and 1 g prior to the evening meal, daily after 1 month of the treatment. This led to a cease in these side-effect symptoms.

Current state: The improvements disclosed above remained unchanged on the lower dosage medication (1 g/1 g/1 g) for over 4 months. The side effects have not returned. The frequency of falls is currently between 0-1/month.

Example 28

Subject The subject is a 66-year old male with no apparent dysfunction in cognitive ability or movement/balance.

Study Design

The subject's reaction speed and alertness was assessed using the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The Psychomotor Vigilance Task (PVT) is a sustained-attention, reaction-timed task that measures the speed with which subjects respond to a visual stimulus. The subject is required to monitor a screen and press the screen as quickly as possible upon the appearance of visual stimuli. The visual stimuli will then disappear and reappear (at irregular time intervals) 10 times over the course of the test, with the subject touching the screen as quickly as possible upon each reappearance. Test performance is quantified from an average of the 10 reaction times. The tests were performed daily under comparable conditions. The subject was assessed for 2 weeks prior to taking acetyl-leucine, which constitutes the baseline period.

From Day 15 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal.

Daily treatments and assessments continued for 4 weeks. The subject then began a 2 week washout period. Due to reported improvement in balance on treatment we measured balancing ability at the end of the treatment period and at the end of the washout period. This assessment required the subject to close their eyes and lift their non-dominant foot around 6 inches off the ground. The subject was then timed to see how long they could remain upright and without significant wobbles. This was repeated three times, and the values averaged. Subjective Measurements

The subject reported an improvement in general alertness and a shortening of the time required to go from 'asleep' to 'fully awake'. He also noticed an improvement in his balance. Objective Measurements

Treatment with 5 g/day Acetyl-DL-Leucine was associated with a significant improvement in Psychomotor Vigilance Task performance, relative to the baseline period (0.444 ms vs 0.307 ms, p<0.0001) (Figure 15A). Upon beginning treatment at Day 15, test performance began to improve, reaching a new, lower baseline that was maintained from Day 19 until the end of the treatment period (Figure 15B). After beginning washout there was a notable decrease in test performance (Figure 15B), although this was not significantly different to the treatment period (0.307 ms (treatment) vs 0.3224 ms (washout), p-0.4747). Test performance during the washout period was also significantly better than in the baseline period (0.322 ms (washout) vs 0.444 ms (baseline), p<0.0001).

Balance was assessed on the last day of the treatment period. The subject was able to remain balanced for 7.27 seconds (average of 3 tests). This test was repeated at the end of the washout period. The length of time subject could remain balanced had decreased to 4.01 seconds (average of 3 tests). Adverse Events

The subject reported feeling a mild dizziness/lightheadedness on one occasion during the first week on medication. The subject reduced the daily dose from 5 g to 3 g for one day only and reported that the dizziness/lightheadedness abated. The next day the daily dose was increased back to 5 g. It remained at this level for the remainder of the 4 week treatment period, with no recurrence of dizziness or lightheadedness.

Example 29

Subject

The subject is a 29-year old male with no apparent dysfunction in cognitive ability or movement/balance.

Study Design The subject's reaction speed and alertness was assessed via the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The tests were performed daily under comparable conditions. The subject was assessed for 2 weeks prior to taking acetyl- leucine, which constitutes the baseline period. From Day 15 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal. Daily treatments and assessments continued for 4 weeks. The subject then began a 2 week washout period. Subjective Measurements

The subject reported an improvement in general alertness. He also reported a decrease in anxiety, possibly linked to being able to think with a clearer head. He reported no difference in balance.

Objective Measurements Treatment with 5 g/day Acetyl-DL-Leucine was associated with a small but statistically significant improvement in Psychomotor Vigilance Task performance, relative to the baseline period (0.3145 ms vs 0.3032 ms, p<0.05) (Figure 16A). Test performance was not significantly different during the washout period from either the baseline or on- treatment values (0.3032 ms vs 0.3145/0.3104 ms respectively). Adverse Effects

None reported.

Example 30

Subject The subject is a 55-year old female with no apparent dysfunction in cognitive ability or movement/balance.

Study Design The subject's reaction speed and alertness was assessed via the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The tests were performed daily under comparable conditions. The subject was assessed for 2 weeks prior to taking acetyl- leucine, which constitutes the baseline period. From Day 15 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2g upon waking, 1.5g prior to lunch and 1.5 g prior to the evening meal. Daily treatments and assessments continued for 4 weeks. The subject then began a 2 week washout period. Balancing ability was measured at the end of the treatment period and at the end of the washout period. This assessment required the subject to close their eyes and lift their non- dominant foot around 6 inches off the ground. The subject was then timed to see how long they could remain upright and without significant wobbles. This was repeated three times, and the values averaged. Subjective Measurements

The subject reported a shortening of the time required to go from 'asleep' to 'fully awake'. The treatment period coincided with travel for work, and a time difference of 8 hrs.

Objective Measurements

Treatment with 5 g/day Acetyl-DL-Leucine was not associated with significant changes in Psychomotor Vigilance Task performance, relative to the baseline period (0.2983 ms (baseline) vs 0.3025 ms (treatment), p- 5105) (Figure 17A). Test performance was not significantly different during the washout period from either the baseline or on-treatment values (0.3053 ms vs 0.2983/0.3025 ms respectively. Observation of individual day's results from the baseline and treatment period suggest that the values during the treatment period may show relatively little variation (Figure 17B).

The absence of a significant change in Psychomotor Vigilance Task performance may be due to the subject having a relatively fast baseline reaction speed.

Balance was assessed on the last day of the treatment period. The subject was able to remain balanced for 12 seconds (average of 3 tests). This test was repeated at the end of the washout period. The length of time subject could remain balanced had decreased to 8 seconds (average of 3 tests).

Adverse Effects None reported.

Example 31

Subject

The subject is a 50-year old male with no apparent dysfunction in cognitive ability or movement/balance. Study Design

The subject's reaction speed and alertness was assessed via the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The tests were performed daily under comparable conditions. The subject was assessed for 1 week prior to taking acetyl-leucine, which constitutes the baseline period. From Day 8 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal. Daily treatments and assessments continued for 2 weeks. The subject then began a 1 week washout period. Subjective Measurements

The subject reported no difference between on and off medication.

Objective Measurements

Treatment with 5 g/day Acetyl-DL-Leucine was associated with a small, non-statistically significant decline in Psychomotor Vigilance Task performance, relative to the baseline period (0.3112 ms (baseline) vs 0.3365 ms (treatment), p- 0.1545) (Figure 18A). Test performance was not significantly different during the washout period from either the baseline or on-treatment values (0.3129 ms vs 0.31 12/0.3365 ms respectively).

The absence of a significant change in Psychomotor Vigilance Task performance may be due to the subject having a relatively fast baseline reaction speed. Adverse Effects

None reported.

Example 32

Subject The subject is a 53-year old male with no apparent dysfunction in cognitive ability or movement/balance.

Study Design

The subject's reaction speed and alertness was assessed via the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The tests were performed daily under comparable conditions. The subject was assessed for 2 weeks prior to taking acetyl- leucine, which constitutes the baseline period.

From Day 15 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal. Daily treatments and assessments continued for 4 weeks. The subject then began a 2 week washout period.

We measured balancing ability at the end of the treatment period and at the end of the washout period. This assessment required the subject to close their eyes and lift their non- dominant foot around 6 inches off the ground. The subject was then timed to see how long they could remain upright and without significant wobbles. This was repeated three times, and the values averaged.

Subjective Measurements

The subject reported an improvement in general alertness and a shortening of the time required to go from 'asleep' to 'fully awake'.

Objective Measurements

Treatment with 5 g/day Acetyl-DL-Leucine was associated with statistically significant improvements in Psychomotor Vigilance Task performance, relative to the baseline period (0.3771 ms (baseline) vs 0.3385 ms (treatment), p<0.01) (Figure 19A). Test performance showed a statistically significant decline during the washout period (0.423 ms) relative to on-treatment (0.3385 ms, p<0.01) values, but was not significantly different relative to baseline (0.3771 ms, ns).

Balance was assessed on the last day of the treatment period. The subject was able to remain balanced for 7.9 seconds (average of 3 tests). This test was repeated at the end of the washout period. The length of time subject could remain balanced had decreased to 3.1 seconds (average of 3 tests).

Adverse Effects None reported.

Example 33

Subject

The subject is a 48-year old woman with no apparent dysfunction in cognitive ability or movement/balance.

Study Design The subject's reaction speed and alertness was assessed via the Mind Metrics App (Psychomotor Vigilance Task, 10 trials per test). The tests were performed daily under comparable conditions. The subject was assessed for 2 weeks prior to taking acetyl- leucine, which constitutes the baseline period. From Day 15 onwards, the subject took 5 g Acetyl-DL-Leucine (Tanganil ^® 500 mg, Pierre Fabre) daily. Medication was taken at least 2 hours after and 30 minutes prior to eating. The 5 g daily dose was taken in 3 separate doses throughout the day - 2 g upon waking, 1.5 g prior to lunch and 1.5 g prior to the evening meal. Daily treatments and assessments continued for 4 weeks. Subject then began a 2 week washout period. Subjective Measurements

The subject reported feeling less tired than usual and taking less time than was usual to go from asleep to fully awake.

Objective Measurements

Treatment with 5 g/day Acetyl-DL-Leucine was associated with statistically significant improvements in Psychomotor Vigilance Task performance, relative to the baseline period (0.3238 ms (baseline) vs 0.2996 ms (treatment), p<0.001) (Figure 20A). Test performance showed a statistically significant decline during the washout period (0.3374 ms) relative to on-treatment (0.2996 ms, p<0.001) values, but was not significantly different relative to baseline (0.3238 ms, ns). Adverse Effects

None reported.

Taken together, these examples demonstrate the utility of leucine and acetyl-leucine in benefiting a range of subjects, including the elderly, in terms of mobility and cognitive function. This is advantageous, since few therapeutic options are currently offered to patients with these very frequent signs and symptoms of ageing. Table 37 summarizes the data from Examples 28-33. As can be seen, acetyl-leucine is shown to increase cognitive function and/or mobility. Moreover, those subjects with high baseline reaction times showed most clinical benefit Table 37