PRIORITY BENEFIT

[0001] This application claims the benefit of U.S. provisional application No. 61/735,968, filed on December 11, 2012, U.S. provisional application No. 61/864,460, filed on August 9, 2013, and U.S. provisional application No. 61/871,754, filed on August 29, 2013, each of which is incorporated herein by reference in its entirety.

1. FIELD OF INVENTION

[0002] The invention relates to treatment of patients with Parkinson's disease and, in particular, motor impairments in patients with Parkinson's disease, using an aminopyridine.

2. BACKGROUND

2.1 Parkinson's Disease

[0003] Parkinson's disease (PD) is a central nervous system degenerative disorder. It is also known as idiopathic parkinsonism, or idiopathic Parkinson's disease. The cause of the disease remains unknown, but it is manifested by an impairment in neurons in the substantia nigra of the brain, resulting in lack of production of dopamine, a neurotransmitter. The reduction in dopamine levels can cause movement impairments via irregular nerve firing in the brain (National Institute of Neurological Disorders and Stroke, January 2006, NIH Publication No. 06- 139). Major motor impairments associated with PD include tremor, rigidity, bradykinesia, and postural instability.

[0004] Current pharmaceutical treatments for Parkinson's disease focus on dopaminergic agents, which either mimic dopamine, or increase levels of dopamine in the body. The most common therapy is levodopa, which is a metabolic precursor of dopamine. However, long term levodopa therapy is often accompanied by dyskinesias, which are sudden, involuntary

movements. Additionally, an "on-of ' effect develops with long term levodopa therapy, wherein the patient experiences normal movement during "on" times, and reverts to PD-related motor impairment during "off times. As levodopa therapy progresses, these side effects increase, and the "off times last longer. Other dopaminergic agents, anticholinergics and/or amantadine also are used either alone, or in combination with levodopa therapy. See Houghton et al., 2008, Parkinson's Disease: Medications, 4 Ed.

[0005] Surgical procedures such as deep brain stimulation have also been employed to alleviate symptoms of Parkinson's disease. Recent studies have shown that certain regions of the brain are hyperactive in PD and may be contributing to PD tremors, and cortical stimulation has been shown to improve symptoms of PD in a mouse model and in humans (Ni et al., 2010 Ann. Neurol. 68:816-824; Gradinaru et al, 17 April 2009 Science 324 (5925), 354-359; Khedr et al, 2006 Movement Disorders 21 :2201-2205; Helmich et al, 2011 Ann. Neurol. 69:269-281).

[0006] Although current therapies can alleviate some of the symptoms of PD, they have variable effectiveness, and are accompanied by unwanted side effects. Additionally, the patient's response to these therapies often decreases over time. Thus, there is an unmet medical need for additional drugs or therapies to alleviate the symptoms, such as motor symptoms, related to Parkinson's disease.

2.2 Aminopyridines

[0007] An exemplary property of certain aminopyridines is that they are potassium channel blockers. 4-aminopyridine (4-AP) is an example of an aminopyridine with such potassium channel blocking properties. At 4-AP plasma concentrations obtained in clinical studies, which are typically <1 microM (94 ng/mL ^"1 ), the potassium channel blocking activity of 4-AP appears to be selective for certain types of these channels. Interestingly, at high concentration (such as at millimolar concentrations) 4-AP is a broad-spectrum blocker of potassium channels. The clinical neurologic effects of 4-AP are consistent with the molecular mechanism of potassium channel blockade. At the cellular level, this action may increase neuronal excitability, relieve conduction block in demyelinated axons, and potentiate synaptic and neuromuscular transmission.

[0008] Studies of 4-aminopyridine have been conducted using intravenous (i.v.) administration and oral administration with immediate-release (IR), controlled-release (CR) or sustained-release (SR) formulations. Administration of IR capsules resulted in rapid and short- lasting peaks of 4-aminopyridine in the plasma. Early pharmacokinetic studies were conducted using an immediate release (IR) formulation for oral administration, which consisted of 4- aminopyridine powder in a gelatin-based capsule or oral solution. Administration resulted in rapidly changing 4-aminopyridine plasma levels that were not well tolerated. A sustained- release matrix tablet was then developed. The 4-aminopyridine-SR matrix tablet showed improved stability and an appropriate pharmacokinetic profile for dosing twice daily.

[0009] Sustained release compositions of 4-aminopyridine and related use of such compositions are set forth, e.g., in US Patent 5,370,879; US Patent 5,540,938; US Patent

8,007,826; and US Patent Publication US2005-0228030. For example, suitable formulations, methods of manufacture, pharmacokinetic characteristics of sustained release aminopyridine compositions and methods of treating various neurological disorders are further described in U.S. Patent No. 8,007,826 entitled "Sustained Release Aminopyridine Composition" issued on August 30, 2011; and U.S. Patent Publication No. 2005-0228030 entitled "Methods of Using Sustained Release Aminopyridine Compositions" published on October 13, 2005; the contents of each of which are incorporated herein by reference in their entireties.

[0010] Dalfampridine is the United States Adopted Name (US AN) for the chemical 4- aminopyridine (4-AP). It is FDA-approved as an extended release (ER), 10 mg tablet (see Ampyra ^® package insert) indicated to improve walking in subjects with multiple sclerosis (MS), as demonstrated by an increase in walking speed. The approved therapeutic dose of

dalfampridine is a 10 mg extended release tablet to be taken twice daily, approximately 12 hours apart, with or without food.

[0011] The effectiveness of dalfampridine in improving walking in patients with multiple sclerosis was evaluated in two double-blind, placebo-controlled phase 3 trials involving a total of 540 patients (Goodman et al, 2009 Lancet 373: 732-738; Goodman et al, 2010 Ann. Neurol. 68:494-502). The primary measure of efficacy in both trials was walking speed (in feet per second) as measured by the Timed 25-foot Walk (T25FW), using a responder analysis. A Responder was defined as a patient who showed faster walking speed for at least three visits out of a possible four during the double-blind period than the maximum value achieved in the five non-treatment visits. A statistically significantly greater proportion of patients taking

dalfampridine-ER 10 mg twice daily were Responders, compared to patients taking placebo. During the double-blind treatment period, a statistically significantly greater proportion of patients taking dalfampridine had increases in walking speed of at least 10%, 20%, or 30% from baseline, compared to placebo. In both trials, consistent improvements in walking speed were shown to be associated with improvements on a patient self-assessment of ambulatory disability, the 12-item Multiple Sclerosis Walking Scale (MSWS-12). [0012] Leg strength, assessed using the Lower Extremity Manual Muscle Test (LEMMT) was also studied in patients with multiple sclerosis. Leg strength was found to be statistically significantly improved with dalfampridine relative to placebo (p<0.05) (Goodman et al., 2008 Neurology 71 : 1134-1141; Goodman et al, 2009 Lancet 373: 732-738; Goodman et al, 2010 Ann. Neurol. 373: 494-502).

[0013] The effects of 4-AP on cortical facilitation have been studied (see Mainero et al., 2004 Neurology 62(11):2044-50). In addition, a double-blind, crossover clinical trial of 3,4- DAP in Essential Tremor (ET) was performed; however, no beneficial effect was detected (see Lorenz et al, 13 Jun 2006 Neurology 66(11): 1753-5).

[0014] In a 6-hydroxydopamine-induced rat model of Parkinson's disease, it was observed that administration of 4-AP at a high dose attenuated functional asymmetry in an apomorphine -induced rotational test, which effect was not confirmed by an elevated body swing test (Haghdoost-Yazdi et al, 2011 Behav. Brain Res. 223, 70-74).

[0015] Citation of a reference herein shall not be construed as an admission that such is prior art to the present invention.

3. SUMMARY OF THE INVENTION

[0016] Provided herein are methods for treatment of an impairment associated with Parkinson's disease in a human patient in need thereof, said method comprising administering to the patient an aminopyridine or a pharmaceutically acceptable salt thereof. In particular, disclosed herein is treatment that causes improvement in one or more motor impairments related to Parkinson's disease. In particular, the use of aminopyridines in such treatments is disclosed. In one embodiment, one or more aminopyridines are used in the methods disclosed herein. In one embodiment, the aminopyridine is a mono- or di-aminopyridine. In some embodiments, the mono-aminopyridine is 3 -aminopyridine or 4-aminopyridine. In one embodiment, the di- aminopyridine is 3,4-diaminopyridine. In another embodiment, the mono-aminopyridine is 4- aminopyridine.

[0017] In specific embodiments, the patient is administered a pharmaceutically acceptable salt of an aminopyridine. In certain embodiments, an aminopyridine itself, and not a pharmaceutically acceptable salt thereof, is used in any of the methods described herein. In preferred embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in a sustained release composition. In other embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an immediate release composition. In certain embodiments, the method in accordance with the invention comprises administering an aminopyridine or a pharmaceutically acceptable salt thereof once daily, twice daily or thrice daily. In other embodiments, the aminopyridine or the pharmaceutically acceptable salt thereof is administered to the patient once daily. In certain embodiments, the aminopyridine or the pharmaceutically acceptable salt thereof is administered to the patient twice daily.

[0018] In a specific embodiment, an aminopyridine (e.g., 4-AP) or a pharmaceutically acceptable salt thereof is in a sustained release composition, and is administered once or twice daily, preferably orally. In another specific embodiment, an aminopyridine (e.g., 4-AP) or a pharmaceutically acceptable salt thereof is in an immediate release composition, and is administered three times or more than three times daily, preferably orally.

[0019] In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof , preferably a therapeutically effective amount of the aminopyridine or salt, is

administered to the patient orally, intravenously, intramuscularly or subcutaneously. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to the patient orally. In some of the embodiments wherein an aminopyridine or a pharmaceutically acceptable salt thereof is administered orally, it is formulated in a form of a tablet, a pill or a capsule.

[0020] In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt, preferably a therapeutically effective amount of the aminopyridine or salt, is administered to the patient orally, in a sustained release composition b.i.d. (i.e., twice daily). In a preferred embodiment, the patient is orally administered 10 mg of 4-aminopyridine twice daily. In certain embodiments, twice daily administration comprises administration of an aminopyridine or a pharmaceutically acceptable salt thereof every 12 hours. In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof in a sustained release composition provides a T _max of about 2 hours to about 6 hours in a human. In another specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof, preferably a therapeutically effective amount of the aminopyridine or salt, is administered to the patient orally, in a sustained release composition once daily.

[0021] In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 4 mg to about 20 mg (e.g., about 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5 or 20 mg) twice daily, preferably in a sustained release composition. In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 4 mg to about 35 mg (e.g., about 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, or 35 mg) once daily, preferably in a sustained release composition. In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 5 mg to 20 mg, 5 mg to 15 mg, 5 mg to 10 mg, 5 mg to 7.5 mg, 7.5 mg to 12.5 mg, or 7.5 mg to 10 mg twice daily, or about 7.5 mg to 20 mg, 7.5 mg to 15 mg, 10 mg to 30 mg, 10 mg to 20 mg, 10 mg to 15 mg, 15 mg to 30 mg, 15 mg to 40 mg, or 20 mg to 40 mg once daily, preferably in a sustained release composition. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 5 mg twice daily, preferably in a sustained release composition. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 7.5 mg twice daily, preferably in a sustained release composition. In another embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 10 mg twice daily, preferably in a sustained release composition. In some of these embodiments, the aminopyridine is 4-aminopyridine. In specific embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 5 mg to 20 mg, 8 mg to 15 mg, 7.5 mg to 12.5 mg, or 10 mg to 15 mg once daily (e.g., in a sustained release

composition). In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 20 mg once daily, preferably in a sustained release composition. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 15 mg once daily, preferably in a sustained release composition. In another embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 10 mg once daily, preferably in a sustained release composition. In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof in a sustained release composition administered at a dose of 5 mg, 7.5 mg, or 10 mg twice daily provides a T _max of about 2 hours to about 6 hours in a human. In a certain

embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof in a sustained release composition administered at a dose of 10 mg, 15 mg, or 20 mg once daily provides a T _max of about 2 hours to about 6 hours in a human.

[0022] Motor impairments, or impairments of motor function, that can be treated in accordance with the methods described herein include, without limitation: general mobility impairments, walking impairments, gait impairments (e.g., gait freezing), unwanted acceleration of walking, postural instability, stooped posture, increase in falls, dystonia, dyskinesia, tremor, rigidity, bradykinesia, micrographia, dexterity impairment, motor coordination impairment, decreased arm swing, akathisia, speech impairment, problematic swallowing, sexual dysfunction, cramping and drooling. In some embodiments, the motor impairment treated in accordance with the methods described herein is either dyskinesia, dystonia, or motor fluctuation. In other embodiments, the motor impairment is either a tremor, bradykinesia, or rigidity. In certain embodiments, the motor impairment treated in accordance with the methods described herein is an impairment in general mobility. In some embodiments, the motor impairment or the general mobility impairment treated in accordance with the methods described herein is an impairment in walking. In one embodiment, the walking impairment treated in accordance with the methods described herein is a decrease in walking speed. In yet another embodiment, the walking impairment treated in accordance with the methods described herein is unwanted acceleration in walking. In specific embodiments, the general mobility impairment or walking impairment treated in accordance with the methods described herein is assessed (before or after

administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using 3D Gait analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement

Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Timed Up and Go Test (TUG), Timed 25-foot Walk Test (T25FW) and/or Freezing of Gait Questionnaire (FOGQ). In another embodiment, the motor impairment treated in accordance with the methods described herein is an impairment in stride time variability. In another embodiment, the motor impairment treated in accordance with the methods described herein is an impairment in double limb support variability.

[0023] In some embodiments, the motor impairment or the general mobility impairment treated in accordance with the methods described herein is an impairment in gait in a patient with PD. In certain embodiments, the impairment treated in accordance with the methods described herein is an abnormal gait in a patient with PD. In some embodiments, the impairment treated in accordance with the methods described herein is an abnormal manner and style of walking (i.e., walking gait) in a patient with PD. For example, impairments in gait that can be treated in accordance with the methods described herein include, without limitation, an impairment in stride length and freezing of gait. In one embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in stride length. In another embodiment, the gait impairment treated in accordance with the methods described herein is freezing of gait. In another embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in spatial gait kinematics. In another embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in turning time. In specific embodiments, the gait impairment treated in accordance with the methods described herein is assessed (before or after administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using 3D Gait analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Timed 25-foot Walk Test (T25FW) and/or Freezing of Gait Questionnaire (FOGQ).

[0024] In some embodiments, the motor impairment treated in accordance with the methods described herein is increase in falls. In certain embodiments, the motor impairment treated in accordance with the methods described herein is a balance impairment, such as postural instability or postural imbalance. In a specific embodiment, gait freezing and/or postural instability in a patient with PD are treated in accordance with the methods described herein. In one embodiment, postural instability in a patient with PD is treated in accordance with the methods described herein.

[0025] In certain embodiments, the motor impairment is assayable by a 3D Gait Analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Freezing of Gait

Questionnaire (FOGQ), Timed Up and Go test (TUG), or a Timed 25-Foot Walk test (T25FW). In specific embodiments, the motor impairment are assessed before and/or after the

administering step, wherein the impairment is assessed using a 3D Gait Analysis, Unified

Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Freezing of Gait Questionnaire (FOGQ), Timed Up and Go test (TUG), or a Timed 25-Foot Walk test (T25FW). In other embodiments, the level of impairment is assessed after repeated administering of the aminopyridine or a pharmaceutically acceptable salt thereof.

[0026] In a specific embodiment, one can combine an aminopyridine or a

pharmaceutically acceptable salt thereof with one or more other agents and/or physical or occupational therapies in concomitant therapy for the treatment of a patient with Parkinson's disease (PD). In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient concomitantly with one or more additional drugs or therapy. Concomitant administration can be concurrently, simultaneously, or sequentially (before or after). In a specific embodiment, concurrent administration can be over the same treatment period, e.g., on the same day, during the same week, or during the same two-week period, the same month, etc. For example, an aminopyridine or a pharmaceutically acceptable salt thereof can be administered concomitantly with another drug or drugs effective for the impairment associated with PD. In certain embodiments, the drug(s) administered concomitantly with an

aminopyridine or a pharmaceutically acceptable salt thereof is a dopaminergic agent, an anticholinergic agent, amantadine, or an adenosine A ₂ A receptor antagonist. In other

embodiments, the patient is concomitantly treated with one or more dopaminergic agents. In some embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a dopamine precursor (e.g., levodopa). In one embodiment, the dopaminergic agent used concomitantly with an aminopyridine or a

pharmaceutically acceptable salt thereof is levodopa. In some embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a dopamine agonist (e.g., apomorphine, bromocriptine, pramipexole, roprinirole or rotigotine). In some embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a drug that inhibits dopamine metabolism (e.g., MAO-B inhibitor, or a COMT inhibitor).

[0027] The Hoehn and Yahr (H & Y) Scale is a categorization of the severity of

Parkinson's disease related symptoms in a patient. The scale is divided into five stages, wherein stage 1 is the mildest form of PD, and stage 5 is the most severe. In one embodiment, the patient treated in accordance with the methods provided herein is stage 1, stage 2, stage 3, stage 4, or stage 5 on the H & Y Scale (or stage 1 to stage 5 on the H & Y Scale). In another embodiment, the patient treated in accordance with the methods provided herein is stage 1, stage 2, or stage 3 on the H & Y Scale (or stage 1 to stage 3 on the H & Y Scale). In further embodiments, the patient treated in accordance with the methods provided herein is stage 1 or stage 2 on the H & Y Scale. In one embodiment, the patient treated in accordance with the methods provided herein is stage 1 on the H & Y Scale. In another embodiment, the patient treated in accordance with the methods provided herein is stage 2 on the H & Y Scale. In yet another embodiment, the patient treated in accordance with the methods provided herein is stage 3 on the H & Y Scale. In a further embodiment, the patient treated in accordance with the methods provided herein is stage 4 on the H & Y Scale.

[0028] In a specific embodiment, provided herein is a method for treating a motor impairment associated with Parkinson's disease in a human patient in need thereof, said method comprising orally administering to the patient a sustained release composition of 4- aminopyridine. In another embodiment, 4-aminopyridine is administered to the patient in an amount of 10 mg twice daily. In certain embodiments, the patient is concomitantly treated with a dopamine precursor and/or a dopamine agonist. In another embodiment, the motor impairment in the patient is an impairment in gait. In yet another embodiment, the motor impairment in the patient is an impairment in walking. In some embodiments, the motor impairment in the patient is a decrease in walking speed. In a specific embodiment, the motor impairment is levodopa- resistant and/or dopaminergic agonist-resistant.

[0029] In a specific embodiment, the impairment is levodopa-resistant and/or

dopaminergic agonist-resistant. In one embodiment, a gait impairment, e.g., freezing of gait, is levodopa-resistant and/or dopaminergic agonist-resistant.

3.1 Terminology

[0030] In order to provide a clear and consistent understanding of the specification and claims, the following definitions are provided:

[0031] As used herein, if no fluid is mentioned or the context does not indicate otherwise, Cminss, C _maxss , C _avss values generally relate to blood plasma.

[0032] The term "gait," as used herein, refers to the pattern of movement of the limbs during locomotion over a solid substrate. In one embodiment, gait is the manner and style of walking.

[0033] The term "improvement" with respect to an impairment designates an alteration in a parameter in a therapeutic direction. As used herein, "improvement" also comprises stabilization of a parameter that would otherwise be deteriorating or moving in a non-therapeutic direction.

[0034] By "pharmaceutically acceptable," it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not prohibited for human or veterinary administration (as the case may be) by a regulatory agency such as the Food and Drug Administration or European Medicines Agency.

[0035] The term "pharmaceutically acceptable salt(s)," with reference to an

aminopyridine, as used herein, refers to a salt prepared from a pharmaceutically acceptable nontoxic acid or base, including an inorganic acid or base, or an organic acid or base. In one embodiment, the pharmaceutically acceptable salt is prepared from a pharmaceutically acceptable non-toxic acid which can be an inorganic or organic acid. In one embodiment, nontoxic acids include, but are not limited to, inorganic and organic acids such as acetic, alginic, anthranilic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethenesulfonic, formic, fumaric, furoic, galacturonic, gluconic, glucuronic, glutamic, glycolic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phenylacetic, phosphoric, propionic, salicylic, stearic, succinic, sulfanilic, sulfuric, tartaric acid, and p-toluenesulfonic acid. In one embodiment, the non-toxic acid is hydrochloric acid.

Suitable pharmaceutically acceptable salts will be apparent to those skilled in the art and include those described in S. M. Barge et al, "Pharmaceutical Salts," 1977, J. Pharm. Sci. 66: 1-19, which is incorporated herein by reference in its entirety.

[0036] Other terms and/or abbreviations are provided below:

Abbreviation or Specialist Term Explanation

Cmaxss Maximum measured plasma concentration at steady state

Cmin Minimum measured plasma concentration

Cminss Minimum measured plasma concentration at steady state

CNS Central nervous system

COMT Catechol-O-methyltransferase

CR Controlled release

Dalfampridine Fampridine, 4-aminopyridine

Dalfampridine-ER Dalfampridine-Extended Release, AMPYRA

DAP Di-aminopyridine

ER Extended release

Fampridine Dalfampridine, 4-aminopyridine

FOGQ Freezing of gait questionnaire

g, kg, mg, μg, ng Gram, kilogram, milligram, microgram, nanogram

GLP Good Laboratory Practice

h, hr Hour

H & Y Hoehn and Yahr

HPLC High performance liquid chromatography

IMAO-B MAO-B inhibitor

IR Immediate release

IRB Institutional Review Board

IV, i.v., or iv Intravenous

K ⁺ Ionic Potassium Abbreviation or Specialist Term Explanation

L, mL Liter, milliliter

LEMMT Lower Extremity Manual Muscle Test

LCMS, LC/MS/MS Liquid chromatography/ mass spectrometry

MAO-B Monoamine oxidase B

MDS-UPDRS Movement Disorder Society-Unified Parkinson's

Disease Rating Scale

Min Minute

MoCA, MOCA Montreal Cognitive Assessment

mM, μΜ Millimolar, micromolar

MS Multiple sclerosis

MSWS-12 12-item Multiple Sclerosis Walking Scale

NF National Formulary

PD Parkinson's disease

p.o. Oral

q.d. (qd) Once a day

SR Sustained-release

ss Steady state

T25FW Timed 25 Foot Walk

t.i.d. (tid) Three times daily

T ¹ max Time of the maximum measured plasma

concentration post-dose

TUG Timed Up and Go

UPDRS Unified Parkinson's Disease Rating Scale

USP United States Pharmacopeia

WS Walking speed Abbreviation or Specialist Term Explanation

3AP, or 3-AP 3 -aminopyridine

4AP, or 4-AP 4-aminopyridine

3,4 DAP, or 3,4-DAP 3 ,4-di-aminopyridine

4. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 shows information regarding 4-aminopyridine.

[0038] Figure 2 is a schematic showing the timetable of 4-AP and placebo dosing for the crossover trial described in Example 1 , Section 6.1.2.1.

[0039] Figure 3A shows Timed Up and Go Test (TUG) changes after 4-AP

administration. Measurements were performed in triplicates at the following time points:

pretreatment (1-pre), 2 hours after administration of 4-AP (2 -post), after 48 hours (3-48h), 30 days post 4-AP (4-30d) and repeated at 90 days pre 4-AP (5-pre/90d) and post 4-AP (6-post).

[0040] Figure 3B shows stride length changes after 4-AP administration. Stride is expressed as percentage from patient height. Measurements were performed at the following time points: pretreatment (1-pre), 2 hours after administration of 4-AP (2 -post), after 48 hours (3- 48h), 30 days post 4-AP (4-30d) and repeated at 90 days pre 4-AP (5-pre/90d) and post 4-AP (6- post).

5. DETAILED DESCRIPTION

5.1 Aminopyridines for Use in the Methods of the Invention

[0041] The invention provides use of an aminopyridine or a pharmaceutically acceptable salt thereof for treating a patient with Parkinson's disease (PD) and, in particular, for treating impairments associated with PD in a patient with PD. In particular embodiments, disclosed herein are uses of an aminopyridine or a pharmaceutically acceptable salt thereof for treating a motor impairment, such as an impairment in gait, in a patient with PD.

[0042] The structure of an aminopyridine is well known in the art. As shown in U.S. Patent No. 5,952,357, a mono- or diaminopyridine has the following structure:

, wherein x is 1 or 2.

[0043] Aminopyridines having the above structural formula wherein x is 1 are, e.g., 2- aminopyridine, 3- aminopyridine and 4- aminopyridine. Aminopyridine compounds having the above structural formula wherein x is 2 are, e.g., 2,3-diaminopyridine; 2,5- diaminopyridine; 2,6- diaminopyridine; 3,4- diaminopyridine; 4,5- diaminopyridine and 4,6- diaminopyridine.

[0044] In one embodiment, the aminopyridine is a mono- or di-aminopyridine. In one embodiment, the mono-aminopyridine is 3 -aminopyridine or 4-aminopyridine. In one

embodiment the di-aminopyridine is 3,4-diaminopyridine.

[0045] As will be appreciated, a pharmaceutically acceptable salt of an aminopyridine may be used instead of or in addition to an aminopyridine in any or all of the methods of treating discussed herein. Thus, in specific embodiments, a pharmaceutically acceptable salt of an aminopyridine (i.e., any pharmaceutically acceptable salt of any of the aminopyridine

compounds listed above) is used in the methods of treating a patient with PD, e.g., a motor impairment in a patient with PD, described herein. These salts can be prepared, for example, in situ during the final isolation and purification of the compounds or by separately reacting the purified compound in its free base form with a suitable organic or inorganic acid and isolating the salt thus formed. In some embodiments, a salt of a mono- or di-aminopyridine is used in the methods of the invention. In another embodiment, a salt of 3 -aminopyridine or 4-aminopyridine is used. In yet another embodiment, a salt of 3,4-diaminopyridine is used. In some embodiments, the pharmaceutically acceptable salt of an aminopyridine is prepared using acetic, alginic, anthranilic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethenesulfonic, formic, fumaric, furoic, galacturonic, gluconic, glucuronic, glutamic, glycolic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phenylacetic, phosphoric, propionic, salicylic, stearic, succinic, sulfanilic, sulfuric, tartaric acid, or p-toluenesulfonic acid. In one embodiment, one equivalent of an aminopyridine, as used herein, may form an acid salt with less than one or with one or more than one equivalent of an acid. In one embodiment an aminopyridine, as used herein, may form a dihydrochloride salt. In one embodiment an aminopyridine, as used herein, may form a phosphate salt. For further description of pharmaceutically acceptable salts that can be used in the methods described herein see, for example, S. M. Barge et al., "Pharmaceutical Salts," 1977, J. Pharm. Sci. 66: 1-19, which is incorporated herein by reference in its entirety.

[0046] In preferred embodiments, an aminopyridine itself, and not a pharmaceutically acceptable salt thereof, is used in any of the methods of treating PD, e.g., a motor impairment in a patient with PD, described herein.

5.2 Impairments Treated in Accordance with the Invention

[0047] The invention provides for treatment of patients who have Parkinson's disease (PD). In particular, the invention provides for treatment of one or more impairments associated with PD in a patient with PD. In a specific embodiment, the impairment is levodopa-resistant and/or dopaminergic agonist-resistant. In certain embodiments, provided herein are methods for treating one or more motor impairments in a patient with PD. In a specific embodiment, provided herein are methods for treating a walking impairment, for example a gait impairment, in a patient with PD. Such treating can be by administering any of the doses and dosage regimens described in this application.

[0048] Motor impairments, or impairments of motor function, that can be treated in accordance with the methods described herein include, without limitation: general mobility impairments, walking impairments, gait impairments (e.g., gait freezing), unwanted acceleration of walking, postural instability, stooped posture, increase in falls, dystonia, dyskinesia, tremor, rigidity, bradykinesia, micrographia, dexterity impairment, motor coordination impairment, decreased arm swing, akathisia, speech impairment, problematic swallowing, sexual dysfunction, cramping and drooling. Additional motor impairments that can be treated in accordance with the methods described herein include, without limitation: global body control impairments, coordination or balance impairments, endurance impairment, impairment in hand function, fine hand coordination loss or impairment, impairment in grip strength, impairment in hand strength, impairment in manual dexterity, muscle weakness, muscle tone impairment, range of motion impairment, spasticity, strength impairment/weakness, impairment in limb function, upper extremity function impairment, lower extremity function impairment, impairment in lower extremity muscle strength, speech impairments (e.g., dysarthria), impairment in jaw function, impairment in chewing, and impairment in jaw articulation. In a specific embodiment, the motor impairment is levodopa-resistant and/or dopaminergic agonist-resistant.

[0049] In certain embodiments, the motor impairment treated in accordance with the methods described herein is an impairment in general mobility. In some embodiments, the motor impairment or the general mobility impairment treated in accordance with the methods described herein is an impairment in walking. For example, impairments in walking that can be treated in accordance with the methods described herein include, without limitation, an impairment in walking velocity (walking speed) and unwanted acceleration in walking. In one embodiment, the walking impairment treated in accordance with the methods described herein is an

impairment in walking velocity (walking speed). In yet another embodiment, the walking impairment treated in accordance with the methods described herein is unwanted acceleration in walking. In specific embodiments, the general mobility impairment or walking impairment treated in accordance with the methods described herein is assessed (before or after

administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using 3D Gait analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement

Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Timed Up and Go Test (TUG), Timed 25-foot Walk Test (T25FW) and/or Freezing of Gait Questionnaire (FOGQ). In another embodiment, the motor impairment treated in accordance with the methods described herein is an impairment in stride time variability. In another embodiment, the motor impairment treated in accordance with the methods described herein is an impairment in double limb support variability.

[0050] In some embodiments, the motor impairment or the general mobility impairment treated in accordance with the methods described herein is an impairment in gait. In certain embodiments, the impairment treated in accordance with the methods described herein is an abnormal gait in a patient with PD. In some embodiments, the impairment treated in accordance with the methods described herein is an abnormal manner and style of walking (i.e., walking gait) in a patient with PD. For example, impairments in gait that can be treated in accordance with the methods described herein include, without limitation, an impairment in stride length and freezing of gait. In one embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in stride length. In another embodiment, the gait impairment treated in accordance with the methods described herein is freezing of gait. In another embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in spatial gait kinematics. In another embodiment, the gait impairment treated in accordance with the methods described herein is an impairment in turning time. In another embodiment, the impairment in gait is levodopa-resistant and/or dopaminergic agonist-resistant. In specific embodiments, the gait impairment treated in accordance with the methods described herein is assessed (before or after administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using 3D Gait analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Timed 25-foot Walk Test (T25FW) and/or Freezing of Gait Questionnaire (FOGQ).

[0051] In some embodiments, the motor impairment or an impairment in general mobility treated in accordance with the methods described herein is an impairment in basic mobility skills such as walking, turning and/or changing the position from sitting to standing (or standing to sitting). In specific embodiments, the general mobility impairment treated in accordance with the methods described herein is assessed (before or after administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using Timed Up and Go Test (TUG). In a specific embodiment, the motor impairment is levodopa-resistant and/or dopaminergic agonist-resistant.

[0052] In another embodiment, the impairment in walking treated in accordance with the methods described herein is a decrease in walking speed. In specific embodiments, the walking speed impairment treated in accordance with the methods described herein is assessed (before or after administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using Timed 25-foot Walk Test (T25FW).

[0053] In some embodiments, the motor impairment treated in accordance with the methods described herein is increase in falls. In certain embodiments, the motor impairment treated in accordance with the methods described herein is a balance impairment, such as postural instability or postural imbalance. In one embodiment, an impairment in postural balance treated in accordance with the methods described herein can be an impairment in postural balance while not in locomotion over a solid substrate. In another embodiment, an impairment in postural balance treated in accordance with the methods described herein can be an impairment in postural balance while in locomotion over a solid substrate. In particular embodiments, the methods provided herein are for treating a postural balance impairment or postural instability in a patient with PD when the patient is sitting, standing, reaching,

maintaining single-leg stance, and/or turning. In specific embodiments, the increase in falls treated in accordance with the methods described herein is assessed (before or after

administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using Freezing of Gait Questionnaire (FOGQ).

[0054] In a specific embodiment, gait freezing and/or postural instability in a patient with PD are treated in accordance with the methods described herein. In one embodiment, postural instability in a patient with PD is treated in accordance with the methods described herein.

[0055] In some embodiments, the motor impairment treated in accordance with the methods described herein is dyskinesia, dystonia and/or a motor fluctuation (e.g., "ON'VOFF" fluctuation in responsiveness to a therapy with another drug, e.g., a dopaminergic agent). In one embodiment, the motor impairment treated in accordance with the methods described herein is dyskinesia and/or dystonia. In specific embodiments, the motor impairment (e.g., dyskinesia, dystonia or fluctuation) treated in accordance with the methods described herein is assessed (before or after administration of an aminopyridine or a pharmaceutically acceptable salt thereof), or assayable, using Unified Parkinson's Disease Rating Scale (UPDRS) or Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS).

[0056] In other particular embodiments, the motor impairment treated in accordance with the methods described herein is a tremor, bradykinesia, or rigidity.

[0057] In certain embodiments, provided herein are methods for treating an impairment in one or more (e.g., one, two, three, four or more than four) parameters of gait in a patient with PD. Parameters of gait include, without limitation, step width, step or stride length, step speed, step time, step length symmetry, step length/leg length ratio, velocity (e.g., endpoint sway velocity), base of support (e.g., dynamic base of support) and percentage of gait cycle spent in double or single support per walking trial. In some embodiments, parameters of gait include, without limitation, freezing of gait, posture, length of stride, width of base, speed and/or fluidity of motion, arm swing, bilateral symmetry of motor activity, and neurological deficits or signs. In a specific embodiment, the impairment in gait is levodopa-resistant and/or dopaminergic agonist- resistant.

[0058] The motor functions, including impairment of motor functions and improvement in motor functions, of the patient can be assessed using any method known in the art. For example, assessment tests can include, without limitation the Timed 25 Foot Walk Test (T25FW), 3D Gait Analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS,

Freezing of Gait Questionnaire (FOGQ), and the Timed Up and Go Test (TUG). T25FW can be used to assess walking and gait. 3D Gait Analysis can be used to assess gait. In particular, 3D Gait Analysis can be used to measure gait velocity and/or stride length (e.g., Peak Motus® Software, Peak Performance, Centennial, CO can be used in the methods described herein).

UPDRS can be used to measure motor and non-motor functions in a patient with PD. In particular, UPDRS can be used to assess such motor impairments such as dyskinesias,

fluctuations or dystonia. FOGQ is another test that can be used to assess gait. In particular, FOGQ can be used to assess freezing of gait. In some embodiments, FOGQ can be used to assess susceptibility of a patient to falls. TUG can be used to assess general mobility in a patient. In particular, TUG can be used to assess basic mobility skills, e.g., in people who are elderly or have neurological conditions. TUG may evaluate sit-to-stand, walking (e.g., 3 minute walking), turning, and/or returning to the chair functions in a patient. Such assessments can be performed before and after administration of an aminopyridine or a pharmaceutically acceptable salt thereof to a patient in accordance with the methods disclosed herein. For example, a motor function in a patient with PD can be assessed before administering an aminopyridine and/or after

administering an aminopyridine (or a pharmaceutically acceptable salt thereof), e.g., at or after 1,

2, 3, 4, 5, 6, 7, 8, 9, 10 days; 1, 2, 3, 4, 5, 6, 7, 8 weeks; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 months; or 1, 2,

3, 4, 5 years since the commencement of treatment in accordance with the methods described herein. In particular embodiments, the impairments treated in accordance with the methods described herein are impairments (e.g., motor impairments) assayable by one or more of the following tests: the timed 25 Foot Walk Test (T25FW), 3D Gait Analysis, Unified Parkinson's Disease Rating Scale (UPDRS), Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), axial MDS-UPDRS, Freezing of Gait Questionnaire (FOGQ), and the Timed Up and Go Test (TUG).

[0059] In other embodiments, the motor functions, including impairments of motor functions and improvement in motor functions, can be assessed, without limitation, using: 2 minute walk test, 6 minute walk (6MW) test, Box & Block test, Six Spot Step Test, the Manual Muscle test for lower extremity function, Lower Extremity Manual Muscle Test (LEMMT), the Ashworth score, the Modified Ashworth Scale, grip strength test, 9-hole peg test, fine finger movement, rapid alternating fingers for upper extremity function, functional system scoring for sensory function, and finger-to-nose and heel-to-shin for ataxia. In particular, 2 minute walk test or 6MW test can be used to measure walking, LEMMT can be used to measure lower extremity muscle strength, and the Modified Ashworth Scale can be used to measure spasticity.

GAITRite™ technology (e.g., 26 foot GAITRite™) can be used to measure gait, e.g., stride length and velocity. The NeuroCom SMART Balance Master® can be used to measure gait and balance parameters such as step length. A Step Watch® accelerometer can be used to measure gait. Art-accepted upper extremity function assessments include, without limitation,

performance scale-self-report measures, hand-held dynamometry, and Upper Extremity Index (UEI). Other assessment tests that can be used to measure motor functions include but are not limited to: Berg Balance Scale (BBS), Kela Coordination Test, Postural Stability Test, Timed 10-meter Gait Test, Shoulder Tug Test, Grip Strength, Maximal isometric force of the knee extensors, muscle endurance tests, passive straight leg raise, TEMPA (upper extremity performance test for the elderly), the Jebsen-Taylor Hand Function Test, The Disabilities of the Arm, Shoulder and Hand (DASH) Questionnaire, and Manual Ability Measure-36 (MAM-36). Such assessments can be performed before and after administration of an aminopyridine or a pharmaceutically acceptable salt thereof to a patient in accordance with the methods disclosed herein. For example, a motor function in a patient with PD can be assessed before administering an aminopyridine and/or after administering an aminopyridine, e.g., at or after 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 days; 1, 2, 3, 4, 5, 6, 7, 8 weeks; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 months; or 1, 2, 3, 4, 5 years since the commencement of treatment in accordance with the methods described herein.

[0060] In specific embodiments, the treatment in accordance with the invention is to improve, ameliorate, or reduce the severity of an impairment (e.g., motor impairment such as a gait impairment) in a patient with PD. In certain embodiments, the treatment in accordance with the invention is to improve an impairment (e.g., motor impairment such as a gait impairment) in a patient with PD. In certain embodiments, the treatment in accordance with the invention is to improve general mobility in a patient with PD. In specific embodiments, the treatment in accordance with the invention is to improve gait (e.g., to improve one, two or more parameters of gait) in a patient with PD. In specific embodiments, the treatment in accordance with the invention is to improve freezing of gait, turning time, spatial gait kinematics, stride time variability, double limb support variability, stride velocity or stride length in a patient with PD. In specific embodiments, the treatment in accordance with the invention is to improve postural imbalance or decrease incidence of falls in a patient with PD. In specific embodiments, the treatment in accordance with the invention is to improve dystonia or dyskinesia in a patient with PD. In another specific embodiment, the treatment in accordance with the invention is to improve motor fluctuations in a patient with PD (e.g., "ON'VOFF" fluctuation in responsiveness to a therapy with another drug, e.g., a dopaminergic agent).

[0061] In a specific embodiment, the impairment is levodopa-resistant and/or

dopaminergic agonist-resistant. In a specific embodiment, the impairment in gait is levodopa- resistant and/or dopaminergic agonist-resistant. In a specific embodiment, the motor impairment is levodopa-resistant and/or dopaminergic agonist-resistant.

[0062] In certain embodiments, the level of an impairment can be assessed (e.g., by assessing one, two or more parameters of such impairment) after, or before and after, repeated administration of an aminopyridine or a pharmaceutically acceptable salt thereof. Such method can be any method for evaluating the impairment described herein or known in the art.

[0063] In specific embodiments, treating a PD patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to treat (e.g., improve, ameliorate, alleviate the symptoms of, or reduce the severity of) an impairment, such as a motor impairment, e.g., gait impairment, in a patient with PD. In a specific embodiment, treating a PD patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to eliminate an impairment, such as a motor impairment, e.g., gait impairment, in a patient with PD. The motor impairment that is effectively treated or eliminated as described above can be any motor impairment, e.g., any motor impairment described herein. In one embodiment, the motor impairment is levodopa-resistant and/or dopaminergic agonist-resistant.

[0064] In another embodiment, a method for maintaining improvement of an impairment, such as a motor impairment, e.g., gait impairment, in a patient with PD is provided, said method comprising: administering an amount (e.g., a therapeutically effective amount) of an

aminopyridine (such as 3,4-diaminopyridine, 4-aminopyridine and the like) or a pharmaceutically acceptable salt thereof to said patient after previously achieving an improvement in the impairment in said patient during administration of an aminopyridine. [0065] In one embodiment, a method for treating an impairment or maintaining an improvement in an impairment (such as a motor impairment, e.g., a gait impairment) in a patient with PD comprises administering an amount (e.g., a therapeutically effective amount) of an aminopyridine or a pharmaceutically acceptable salt thereof to said patient over an extended period of time. In another embodiment, a method for achieving sustained improvement in an impairment (such as a motor impairment, e.g., a gait impairment) in a patient with PD comprises continuing administration of an amount (e.g., a therapeutically effective amount) of an aminopyridine (such as 3,4-diaminopyridine, 4-aminopyridine and the like) or a pharmaceutically acceptable salt thereof to said patient over an extended period of time. In a specific embodiment, the extended period of time is at least, or more than, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months.

[0066] In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient for at least or more than: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 days; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22 weeks; 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 months; or 1, 2, 3, 4, 5, 10 or greater than 5 or 10 years.

[0067] In specific embodiments, the improvement(s) in an impairment (such as a motor impairment, e.g., a gait impairment) among patients with PD occur over periods of at least or more than: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21 days; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 or 22 weeks; 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 months; or 1, 2, 3, 4, 5, 10, or greater than 5 or 10 years of treatment with an aminopyridine.

[0068] In a specific embodiment, a therapeutic outcome of treatment in accordance with the methods described herein is assayed for and detected at any one, two, three, four, five or more, or each, of the following time points, and/or at a time point later than any one of the following time points: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, days; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 weeks; 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 36, 42, 48, 54, 60, and 66 months; 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 and 6.5 years post-commencement of treatment with an aminopyridine or a pharmaceutically acceptable salt thereof.

[0069] In a specific embodiment, treating a patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to eliminate a motor impairment associated with PD, and/or effective to regain the motor function impaired by PD. In certain embodiments, the administering of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to restore a motor function impaired by PD. In one embodiment, aminopyridine administration restores one or more motor functions. This is manifest or measured as an improvement, e.g., in motor function, general mobility, walking (e.g., walking velocity), gait (e.g., freezing of gait and/or stride length), postural instability, decrease in falls, dystonia, dyskinesia, answers to art-accepted measures of quality of life, or improvement in any other motor function described herein or known in the art.

[0070] In certain embodiments, treating a patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to prevent a motor impairment, e.g., a gait impairment, associated with PD. In one embodiment, treating a patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to prevent the onset of the symptoms of a motor impairment, e.g., a gait impairment. In other embodiments, treating a patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to alleviate the symptoms of a motor impairment associated with PD. In yet other embodiments, treating a patient by administering an amount of an aminopyridine or a pharmaceutically acceptable salt thereof is effective to decrease the duration of a motor impairment associated with PD. In a specific embodiment, the motor impairment, e.g., gait impairment, is levodopa-resistant and/or dopaminergic agonist-resistant.

[0071] Aminopyridines of the invention or pharmaceutically acceptable salts thereof are administered at a therapeutically effective dosage sufficient to treat an impairment associated with PD in a patient. In certain embodiments, the treatment reduces the amount of symptoms of the impairment in the patient by at least about 10%, more preferably 20%, more preferably by at least about 40%, even more preferably by at least about 60%, and still more preferably by at least about 80%) relative to untreated subjects. Such percent change quantification is preferably applied to assays of motor function that provide measurements of results in continuous linear scales, such as T25FW, etc. Other tests of motor function will not be expressed as percent change but would be predicted to result in a significant change with the appropriate statistical comparison. Such tests include semiquantative measures that assign values to the ability to perform certain skills. In some embodiments, treatment in accordance with the invention results in a statistically significant improvement in a motor impairment associated with PD (e.g., as measured by the patient's ability to perform certain task or skill) in comparison to a control. Such control can be the patient's ability to perform the assessed task or skill prior to the commencement of treatment.

[0072] In one embodiment, the impairment treated in accordance with methods provided herein is not tremor in a patient with PD. In other embodiments, the impairment treated in accordance with methods provided herein can be tremor in a patient with PD.

5.3 Patient identification or selection

[0073] In specific embodiments, the invention further comprises a step of selecting, identifying, or diagnosing a patient with Parkinson's disease, in particular, idiopathic Parkinson's disease, prior to the administering step. In a preferred embodiment of the invention, a patient is selected, identified or diagnosed with PD and with a motor impairment associated with PD (such as any of the motor impairments described in the section above, e.g., an impairment in general motor ability, walking impairment, gait impairment (e.g., gait freezing), balance impairment, postural instability, increased incidence of falls, dyskinesia or dystonia). In a specific embodiment of the invention, a patient is selected, identified or diagnosed with PD and with an impairment in gait. In another embodiment of the invention, a patient is selected, identified or diagnosed with PD and with gait freezing or postural instability.

[0074] The patient treated according to the methods provided herein has Parkinson's disease.

[0075] In certain embodiments, the invention provides for treatment of patients with some degree of motor impairment related to PD. This impairment can range from mild symptoms on one side of the body to wheelchair confinement in the most severe cases. In some embodiments, the patient treated in accordance with the methods described herein has one or more motor impairments (e.g., has been diagnosed with, or exhibits one or more symptoms of a motor impairment). In certain embodiments, the patient treated in accordance with the methods described herein has an impairment due to neuronal damage in the area of the cortex or other region of the brain responsible for or involved with motor functions. Preferred embodiments of the present invention relate to methods of using 4-aminopyridine for treating an impairment of motor function resulting from PD. [0076] In a specific embodiment, a patient treated in accordance with the methods described herein has an impairment which is levodopa-resistant and/or dopaminergic agonist- resistant. In a specific embodiment, a patient treated in accordance with the methods described herein has an impairment in gait (e.g., freezing of gait) which is levodopa-resistant and/or dopaminergic agonist-resistant. In a specific embodiment, a patient treated in accordance with the methods described herein has an motor impairment which is levodopa-resistant and/or dopaminergic agonist-resistant.

[0077] The patients or subjects that are treated by the methods of the invention include, but are not limited to, humans and non-human vertebrates such as wild, domestic and farm animals. In certain embodiments, the patient treated in accordance with the invention is a mammal, e.g., a human, a cow, a dog, a cat, a goat, a horse, a sheep, or a pig. In a preferred embodiment, the patient to whom an aminopyridine or a pharmaceutically acceptable salt thereof is administered is a human. In one embodiment, the human patient is 18 to 55 years old. In another embodiment, the human patient is 18 to 70 years old. In certain embodiments, the human patient is 45 to 80 years old. In other embodiments the human patient is 45 to 70 years old. In some embodiments, the human patient is 16 to 40 years old. In other embodiments, the human patient is greater than 45 years old. In a specific embodiment, the human patient is a female. In yet another specific embodiment, the human patient is a male. In one embodiment, the patient is a human adult.

[0078] In some embodiments, the patient treated in accordance with the methods provided herein does not have a clinical history of seizures and/or epilepsy. For example, the patient has not experienced seizures and/or epilepsy in their lifetime, or has not experienced seizures and/or epilepsy 1, 2, 3, 4 or 5 years, or more than 5 years, prior to administration of an aminopyridine or a pharmaceutically acceptable salt thereof. In yet other embodiments, the patient treated in accordance with the methods provided herein has a clinical history of seizures and/or epilepsy.

[0079] In one embodiment, the patient treated in accordance with the methods provided herein does not have renal impairment. In one specific embodiment, the patient does not have moderate to severe renal impairment (CrCl < 50 mL/min). In yet another embodiment, the patient does not have mild renal impairment (CrCl = 51-80 mL/min). In one embodiment, the patient has mild renal impairment (CrCl = 51-80 mL/min). In another embodiment, the patient treated in accordance with the methods provided herein does not have a clinical history of cardiac arrhythmia. In yet another embodiment, the patient treated in accordance with the methods provided herein has not had deep brain stimulation. In one embodiment, the patient treated in accordance with the methods provided herein does not have severe arthritis. In other embodiments, the patient treated in accordance with the methods provided herein has renal impairment, has a clinical history of cardiac arrhythmia, has had deep brain stimulation, or has severe arthritis.

[0080] The Hoehn and Yahr (H & Y) Scale is a categorization of the severity of

Parkinson's disease related symptoms in a patient. The scale is divided into five stages, wherein stage 1 is the mildest form of PD, and stage 5 is the most severe. In one embodiment, the patient treated in accordance with the methods provided herein is stage 1, stage 2, stage 3, stage 4, or stage 5 on the H & Y Scale (or stage 1 to stage 5 on the H & Y Scale). In another embodiment, the patient treated in accordance with the methods provided herein is stage 1, stage 2, stage 3, or stage 4 on the H & Y Scale (or stage 1 to stage 4 on the H & Y Scale). In yet another embodiment, the patient treated in accordance with the methods provided herein is stage 1 , stage 2, or stage 3 on the H & Y Scale (or stage 1 to stage 3 on the H & Y Scale). In further embodiments, the patient treated in accordance with the methods provided herein is stage 1 or stage 2 on the H & Y Scale. In one embodiment, the patient treated in accordance with the methods provided herein is stage 1 on the H & Y Scale. In another embodiment, the patient treated in accordance with the methods provided herein is stage 2 on the H & Y Scale. In yet another embodiment, the patient treated in accordance with the methods provided herein is stage 3 on the H & Y Scale. In a further embodiment, the patient treated in accordance with the methods provided herein is stage 4 on the H & Y Scale. In yet another embodiment, the patient treated in accordance with the methods provided herein is stage 5 on the H & Y Scale. In one embodiment, the patient treated in accordance with the methods provided herein is stage 3 or lower on the H & Y Scale.

[0081] In one embodiment, the patient treated in accordance with the methods described herein has idiopathic Parkinson's disease, a gait impairment (e.g., freezing of gait) or postural instability, and is stage 1 to stage 3 on the H & Y Scale.

[0082] In some embodiments, the patient is administered another drug or therapy for PD concurrently with administration of an aminopyridine or a pharmaceutically acceptable salt thereof as described herein (see Section 5.6 below). In particular embodiments, the patient is administered a dopaminergic agent (e.g., a dopamine agonist and/or levodopa) concurrently with administration of an aminopyridine or a pharmaceutically acceptable salt thereof as described herein.

[0083] In some embodiments, the patient treated in accordance with the methods described herein has undergone surgery to treat PD.

[0084] In a specific embodiment, a patient treated in accordance with the methods described herein does not have multiple sclerosis.

5.4 Dosing Regimens

[0085] Any of the therapeutic methods described above can be carried out using any of the following dosing regimens. In specific embodiments, the aminopyridine used in such methods is 4-aminopyridine in a sustained release composition.

[0086] In preferred embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in a sustained release composition. In other embodiments, an

aminopyridine or a pharmaceutically acceptable salt thereof is administered in an immediate release composition. In certain embodiments, the method in accordance with the invention comprises administering an aminopyridine or a pharmaceutically acceptable salt thereof once daily, twice daily or thrice daily. In a specific embodiment, an aminopyridine (e.g., 4-AP), or a pharmaceutically acceptable salt thereof, is in a sustained release composition, and is administered once or twice daily, for example, orally. In a specific embodiment, the daily dose of 4-AP is once a day, or is given as two, three, or four equally divided subdoses. In another specific embodiment, an aminopyridine (e.g., 4-AP), or a pharmaceutically acceptable salt thereof, is in an immediate release composition, and is administered one, two, three times or more than three times daily, for example, orally. In one embodiment, a single dose of an aminopyridine or a pharmaceutically acceptable salt thereof (e.g., in an immediate release composition or in a sustained release composition) is administered to a patient.

[0087] In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to the patient orally, in a sustained release composition b.i.d. (i.e., twice daily). In certain embodiments, twice daily administration comprises administration of a compound every 12 hours. [0088] In some embodiments, an aminopyridine in a sustained release composition provides a T _max of about 2 hours to about 6 hours in a human.

[0089] In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to the patient orally, in a sustained release composition once daily.

[0090] In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 4 mg to about 20 mg (e.g., about 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5 or 20 mg) twice daily, preferably in a sustained release composition. In certain embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 4 mg to about 35 mg (e.g., about 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, or 35 mg) once daily, preferably in a sustained release composition. In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 5 mg to 20 mg, 5 mg to 15 mg, 5 mg to 10 mg, 5 mg to 7.5 mg, 7.5 mg to 12.5 mg, or 7.5 mg to 10 mg twice daily, or about 7.5 mg to 20 mg, 7.5 mg to 15 mg, 10 mg to 30 mg, 10 mg to 20 mg, 10 mg to 15 mg, 15 mg to 30 mg, 15 mg to 40 mg, or 20 mg to 40 mg once daily, preferably in a sustained release composition. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 5 mg once daily or twice daily, preferably in a sustained release composition. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 7.5 mg once daily or twice daily, preferably in a sustained release composition. In another embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered at a dose of 10 mg once daily or twice daily, preferably in a sustained release composition. In some of these embodiments, the aminopyridine is 4-aminopyridine. In specific embodiments, an

aminopyridine or a pharmaceutically acceptable salt thereof is administered in an amount ranging from about 5 mg to 20 mg, 8 mg to 15 mg, 7.5 mg to 12.5 mg, or 10 mg to 15 mg once daily (e.g., in a sustained release composition).

[0091] In some embodiments, a patient is treated in accordance with the methods described herein for a period of time that is, e.g., for at least 1 week, at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 6 weeks, at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 5 months, at least 6 months, at least 7 months, at least 8 months, at least 9 months, at least 10 months, at least 11 months, at least 1 year, at least 2 years, at least 3 years, at least 4 years, at least 5 years, at least 10 years, or more than 5 or 10 years. In certain embodiments, the treatment regimen (a particular dose and frequency of administration, which can be selected from any described herein) is stable over a period of time, e.g., for at least 1 week, at least 2 weeks, at least 3 weeks, at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 6 months, or at least 1 year.

[0092] In a specific embodiment, a patient with PD is treated with 5 mg 4-aminopyridine in an immediate release composition thrice daily. In a particular aspect of this embodiment, the impairment being treated is freezing of gait, unwanted acceleration of walking, or an impairment in gait (e.g., stride length, turning time, stride time variability, double limb support variability, velocity, spatial gait kinematics, etc.) as assessed by any method known in the art (e.g., UPDRS, Movement Disorder Society-UPDRS (MDS-UPDRS), axial MDS-UPDRS, TUG test, T25FW, FOGQ, and/or 3D Gait Analysis).

[0093] In one embodiment, a patient with PD is treated with 4-aminopyridine-SR. In one embodiment, the patient is instructed to take the drug twice daily. In one embodiment, the patient is instructed to take 4-aminopyridine-SR in a dose of 4-aminopyridine selected from 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, or 25 mg bid. In one embodiment, one of the daily doses of 4-aminopyridine-SR is different from the other dose, and in a particular embodiment a morning dose is higher than the evening dose. In one embodiment, at least one of the twice daily doses of 4-aminopyridine-SR is 10 mg 4-AP.

[0094] In another embodiment, the patient is instructed to take 4-aminopyridine-SR once daily. In one embodiment, the patient is instructed to take 4-aminopyridine-SR in a dose of 4- aminopyridine selected from 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, 30.5, 31, 31.5, 32, 32.5, 33, 33.5, 34, 34.5, 35, 35.5, 36, 36.5, 37, 37.5, 38, 38.5, 39, 39.5, or 40 mg once daily. In one embodiment, the once daily dose of 4-aminopyridine-SR is 10 mg 4-AP.

[0095] In a specific embodiment, the sustained release composition of an aminopyridine or a pharmaceutically acceptable salt thereof results in the release of the aminopyridine or a pharmaceutically acceptable salt thereof from the dosage formulation at a sustained rate such that a therapeutically beneficial blood level is maintained over a period of at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, hours, or more than 18 hours, or more than 24 hours, or more than 30 hours. Preferably, the amount of the

aminopyridine or a pharmaceutically acceptable salt thereof in the oral dosage formulations according to embodiments of the present invention establishes a therapeutically useful plasma or CNS concentration through t.i.d., b.i.d., or q.d. administration of the pharmaceutical composition. The terms "sustained release" and "extended release" are generally synonymous unless the context clearly indicates otherwise.

[0096] In certain embodiments, a therapeutically effective amount of an aminopyridine or a pharmaceutically acceptable salt thereof is between 4 mg and 17.5 mg (e.g., 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17 or 17.5 mg), or in the range from 4 to 40 mg, and in a specific embodiment, it is administered once daily or twice daily, preferably in a sustained release composition. In specific embodiments, aminopyridine or a pharmaceutically acceptable salt thereof is administered in a sustained release composition. In other specific embodiments, aminopyridine or a pharmaceutically acceptable salt thereof is administered in an immediate release composition. In certain embodiments a therapeutically effective amount of 4- aminopyridine, or a pharmaceutically acceptable salt thereof, is between 4 mg and 17.5 mg (e.g., 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17 or 17.5 mg), or in the range from 4 to 40 mg, and, in a specific embodiment, it is administered once daily or twice daily, preferably in a sustained release composition. In one embodiment, twice daily administration is administration of an aminopyridine or a pharmaceutically acceptable salt thereof every 12 hours.

[0097] In a specific embodiment of any of the methods of treatment described herein, an aminopyridine (e.g., 4-aminopyridine) is administered in an amount in the range of 4 to 17.5 mg (e.g., 4, 5, 6, 7, 7.5, 8, 9, 10, 11, 12, 12.5, 13, 14, 15, 16, 17 or 17.5 mg) twice daily in a sustained release composition, or is administered in an amount in the range of 8 to 40 mg (e.g., 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28 ,29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 mg) once daily in a sustained release composition.

[0098] In one embodiment, a method in accordance with the invention is provided wherein said therapeutically effective amount of an aminopyridine (such as 3,4-diaminopyridine, 4-aminopyridine and the like) or a pharmaceutically acceptable salt thereof is 10 milligrams in a sustained release composition twice daily. [0099] In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is 5 milligrams in a sustained release composition twice daily. In another

embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is 7.5 milligrams in a sustained release composition twice daily. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4- aminopyridine) or a pharmaceutically acceptable salt thereof is 10 milligrams in a sustained release composition twice daily. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a

pharmaceutically acceptable salt thereof is 12.5 milligrams in a sustained release composition twice daily. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is 15 milligrams in a sustained release composition twice daily. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4- aminopyridine) or a pharmaceutically acceptable salt thereof is 17.5 milligrams in a sustained release composition twice daily.

[00100] In some embodiments, a method is provided wherein the therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is 20 milligrams in a sustained release composition once daily. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is 8, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5, 18, 19, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27.5, 30 or 35 milligrams in a sustained release composition once daily.

[00101] In another embodiment, a method in accordance with the invention comprises administration of a therapeutically effective amount of 4-aminopyridine, or a pharmaceutically acceptable salt thereof, in a total daily amount of 8, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5, 18, 19, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27.5, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 milligrams in a sustained release composition. An exemplary embodiment comprises twice daily administration where 15 milligrams in a sustained release composition is administered in the morning; and 10 milligrams in a sustained release composition is administered in the evening. An exemplary embodiment comprises twice daily administration where 12.5 milligrams in a sustained release composition is administered in the morning; and 7.5 milligrams in a sustained release composition is administered in the evening. Another exemplary embodiment comprises administration of a total daily amount in a once daily composition.

[00102] In yet another embodiment, a method in accordance with the invention comprises administration of a therapeutically effective amount of 4-aminopyridine, or a pharmaceutically acceptable salt thereof, in a total daily amount of 8, 10, 11, 12, 12.5, 13, 14, 15, 16, 17, 17.5, 18, 19, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27.5, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 milligrams in an immediate release composition. In some embodiments, an immediate release composition comprising an aminopyridine or a pharmaceutically acceptable salt thereof is administered three times daily or more than three times daily (e.g., 4, 5, or 6 times daily).

[00103] In certain embodiments, an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof is formulated as a sustained-release (SR) or extended release (ER) matrix tablet in various strengths, for example, from 4 to 40 mg, where 5-, 7.5-, 10-, 12.5-, 15-, and 17.5 are presently preferred. One embodiment of 4-aminopyridine-SR is 10 mg which is preferred for b.i.d. dosing, other dosing regimens are within the scope of the invention; accordingly other amounts of active ingredient in sustained-release formulations are also encompassed within the scope of the invention.

[00104] In one dosing embodiment, a sufficient amount of an aminopyridine, such as 4-aminopyridine, is provided such that it elicits the steady state levels that are within the range obtained by use of 4-aminopyridine-SR; in one embodiment these steady state values are a maximum concentration at steady state (C _maxss ) and minimum concentration at steady state

(C _m i _n ss). The steady state values can be plasma levels, levels on the brain side of the blood:brain barrier, or levels in the CSF. Preferably, these are plasma levels.

[00105] In another embodiment a sufficient amount of aminopyridine, such as 4- aminopyridine, is provided that it elicits the steady state levels that differ not more than about 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% from the average steady state level (C _avss ) obtained by use of 4-aminopyridine-SR. The steady state values can be plasma levels, levels on the brain side of the blood:brain barrier, or levels in the CSF. Preferably, these are plasma levels. [00106] In another embodiment, a method in accordance with the invention is described wherein said therapeutically effective amount of an aminopyridine, e.g., 4- aminopyridine, or a pharmaceutically acceptable salt thereof, achieves a C _m i _nss of at least or more than: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 ng/ml. In another embodiment, a method is described wherein said therapeutically effective amount of an aminopyridine (e.g., 4- aminopyridine) or a pharmaceutically acceptable salt thereof achieves an average of at least or more than: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 ng/ml. In some embodiments, a method is described wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof achieves an average of about 20 ng/ml, which comprises an average lower limit value of from 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 ng/ml, and an average upper limit value of 20, 21, 22, 23, 24, 25, 26, or 27 ng/ml. In one embodiment, an amount of drug is given to an individual patient (e.g., a dose amount) wherein that dose amount corresponds to an amount that when administered to a normative or reference population obtains an average C _m i _nss of at least or more than: 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 ng/ml. Fluid or tissue levels (e.g., C _maX ss, C _avS s) in reference population can be referred to as normative values. In another embodiment, a method is described wherein said therapeutically effective amount of an aminopyridine or a

pharmaceutically acceptable salt thereof achieves a C _m i _nss in a range of about 5 to 25 ng/ml, 10 to 18 ng/ml, 13 to 15 ng/ml, or 15 to 30 ng/ml. In another embodiment, a method is described wherein said therapeutically effective amount of an aminopyridine or a pharmaceutically acceptable salt thereof achieves a C _m i _nss of about 20 ng/ml. In another embodiment, a method is described wherein said therapeutically effective amount of an aminopyridine or a

pharmaceutically acceptable salt thereof achieves a C _m i _nss of about 20 ng/ml; in certain

embodiments, a Cmi _nss of about 20 ng/ml comprises a lower limit value of from 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 ng/ml, and an upper limit value of 20, 21, 22, 23, 24, 25, 26, or 27 ng/ml.

[00107] In alternative embodiments, provided is a method of treating a PD-related motor impairment in a patient comprising: administering a therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof to said patient such that a Cmi _nss in a range of 5 to 25 ng/ml, 10 to 20 ng/ml, 15 to 30 ng/ml, or 12 to 20 ng/ml is obtained. In another embodiment, a method for treating a PD-related motor impairment in a patient comprises administering a therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof to said patient such that a C _m i _nss in a range of at least 12 ng/ml to 15 ng/ml is obtained. In another embodiment, a method for treating a PD-related motor impairment in a patient comprises: administering a therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof to said patient such that a C _m i _nss in a range of at least 13 ng/ml to 15 ng/ml is obtained. In one embodiment, an amount of drug is given to an individual patient (e.g., a dose amount) wherein that dose amount corresponds to a dose that when administered to a normative or reference population obtains an average Cmi _nss of at least or more than: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 ng/ml; the plasma levels (e.g., C _m i _nss , C _maxss , C _avss ) in reference population can be referred to as a normative values. In one embodiment, a method in accordance with the invention comprises administering a therapeutically effective amount of an

aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof to a patient such that a C _m i _nss of at least 11 or 12 ng/ml is obtained.

[00108] In certain embodiments, a method in accordance with the invention is provided wherein said therapeutically effective amount of an aminopyridine or a

pharmaceutically acceptable salt thereof achieves a T _max of about 2 hours to about 6 hours in a patient. In some of these embodiments, the aminopyridine or a pharmaceutically acceptable salt thereof is administered in a sustained-release composition (e.g., once daily, twice daily or thrice daily). In one of these embodiments, the aminopyridine is 4-aminopyridine. The therapeutically effective amount of 4-aminopyridine can be any amount disclosed herein. In one embodiment, the patient is a human. In some embodiments, a therapeutically effective amount of 4- aminopyridine administered once daily, twice daily or three times daily in a sustained-release composition achieves a T _max of about 2 hours to about 6 hours in a human.

[00109] In another embodiment, a method in accordance with the invention is provided wherein said therapeutically effective amount of an aminopyridine, e.g., 4- aminopyridine, or a pharmaceutically acceptable salt thereof achieves a C _maxss of the following, or less than the following values: 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, or 20 ng/ml. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof achieves an average C _maxss of the following, or less than the following values: 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, or 20 ng/ml. In one embodiment, an amount of drug is given to an individual patient (e.g., a dose amount) wherein that dose amount corresponds to an amount that when administered to a normative or reference population obtains an average C _maxss of the following, or less than the following values: 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, or 20 ng/ml. Fluid or tissue levels (e.g., C _m i _nss , C _maxss , C _avss ) in reference population can be referred to as normative values. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4- aminopyridine) or a pharmaceutically acceptable salt thereof achieves a C _maxss in a range of about 15 to 30 ng/ml, 25 to 35 ng/ml, 25 to 40 ng/ml, or 35 to 55 ng/ml. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine or a pharmaceutically acceptable salt thereof achieves a C _maxss of about 30 ng/ml. In another embodiment, a method is provided wherein said therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a pharmaceutically acceptable salt thereof achieves a C _maxss in a range that comprises a lower limit value of from 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 ng/ml, and an upper limit value of 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, or 60 ng/ml.

[00110] In another embodiment, a method is described wherein said

therapeutically effective amount of an aminopyridine (e.g., 4-aminopyridine) or a

pharmaceutically acceptable salt thereof achieves an average C _maxss of, or less than: 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, or 20 ng/ml. In one embodiment, an amount of drug is given to an individual patient (e.g., a dose amount) wherein that dose amount corresponds to a dose that when administered to a normative or reference population obtains an average C _maxss of, or less than: 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, or 20 ng/ml; the plasma levels (e.g., C _m i _nss , C _maxss , C _avss ) in reference population can be referred to as a normative values.

[00111] The actual dosage amount of an aminopyridine, a pharmaceutically acceptable salt thereof, or a composition comprising an aminopyridine administered to a subject may be determined by physical and physiological factors such as age, sex, body weight, severity of condition, the type of disease being treated, previous or concurrent therapeutic interventions, idiopathy of the subject and on the route of administration. These factors are readily determined by a skilled artisan. The practitioner responsible for administration will typically determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual subject. The dosage may be adjusted by the individual practitioner in the event of any complication or alteration in patient status.

[00112] Preferably, a sustained release composition of 4-aminopyridine is administered to a patient in the methods of the invention, most preferably at 10 mg 4- aminopyridine twice daily.

5.5 Pharmaceutical Compositions

[00113] The invention also provides pharmaceutical compositions comprising an aminopyridine or a pharmaceutically acceptable salt thereof as described herein. Such pharmaceutical compositions can comprise an amount (e.g., a therapeutically effective amount) of an aminopyridine or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier. In one embodiment, the pharmaceutical composition is suitable for oral administration and can be, for example, a pill, tablet or capsule. Pharmaceutical compositions can be as described, for example, in U.S. Patent Application Publication No. 2005/0276851, published December 15, 2005 and U.S. Patent Application Publication No. 2005/0228030, published October 13, 2005, the contents of each of which are incorporated by reference herein in their entireties. A pharmaceutical composition can be, for example, an immediate release composition, a controlled release composition, or a sustained release composition. In one embodiment, the pharmaceutical composition comprises a sustained release composition of 4- aminopyridine. The pharmaceutical compositions of the invention are administered to a patient for any of the uses described herein.

[00114] An aminopyridine or a pharmaceutically acceptable salt thereof is preferably administered to a patient orally or parenterally in the conventional form of preparations, such as capsules, microcapsules, tablets, granules, powder, troches, pills, suppositories, injections, suspensions, or syrups. Suitable formulations can be prepared by methods commonly employed using conventional, organic or inorganic additives, such as one or more of: an excipient (e.g., sucrose, starch, mannitol, sorbitol, lactose, glucose, cellulose, talc, calcium phosphate or calcium carbonate), a binder (e.g., cellulose, methylcellulose, hydroxymethylcellulose, polypropylpyrrolidone, polyvinylpyrrolidone, gelatin, gum arabic, polyethyleneglycol, sucrose or starch), a disintegrator (e.g., starch, carboxymethylcellulose, hydroxypropylstarch, low substituted hydroxypropylcellulose, sodium bicarbonate, calcium phosphate or calcium citrate), a lubricant (e.g., magnesium stearate, light anhydrous silicic acid, talc or sodium lauryl sulfate), a flavoring agent (e.g., citric acid, menthol, glycine or orange powder), a preservative (e.g., sodium benzoate, sodium bisulfite, methylparaben or

propylparaben), a stabilizer (e.g., citric acid, sodium citrate or acetic acid), a suspending agent (e.g., methylcellulose, polyvinyl pyrroliclone or aluminum stearate), a dispersing agent (e.g., hydroxypropylmethylcellulose), a diluent (e.g., water), and base wax (e.g., cocoa butter, white petrolatum or polyethylene glycol). In some embodiments, suitable formulations of an

aminopyridine or a pharmaceutically acceptable salt thereof can be prepared using one, two, three or more, or all, of the following additives: colloidal silicon dioxide, hydroxypropyl methylcellulose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, and titanium dioxide.

[00115] A pharmaceutically acceptable carrier or vehicle can comprise an excipient, diluent, or a mixture thereof. In some embodiments, suitable formulations (e.g., suitable formulations such as tablets for oral administration) of an aminopyridine or a

pharmaceutically acceptable salt thereof are prepared using one or more of the following excipients: hydroxypropyl methylcellulose, USP; microcrystalline cellulose, USP; colloidal silicon dioxide, NF; magnesium stearate, USP; and Opadry White.

[00116] The amount of an aminopyridine or a pharmaceutically acceptable salt thereof that is present in the pharmaceutical composition is preferably an amount that will exercise the desired effect.

[00117] An aminopyridine or a pharmaceutically acceptable salt thereof can be administered orally. In some of the embodiments wherein an aminopyridine or a

pharmaceutically acceptable salt thereof is administered orally, the composition is formulated in a form of a tablet, a pill or a capsule. An aminopyridine or a pharmaceutically acceptable salt thereof can also be administered intradermally, intramuscularly, intraperitoneally,

percutaneously, intravenously, subcutaneously, intranasally, epidurally, sublingually,

intracerebrally, intravaginally, transdermally, rectally, by inhalation, or topically to the ears, nose, eyes, or skin. In one embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to the patient intravenously. The mode of administration is left to the discretion of the health-care practitioner.

[00118] The compositions can be in the form of tablets, chewable tablets, capsules, solutions, parenteral solutions, troches, suppositories and suspensions and the like.

Compositions can be formulated to contain a daily dose, or a convenient fraction of a daily dose, in a dosage unit, which may be, e.g., a single tablet or capsule or convenient volume of a liquid.

[00119] Capsules can be prepared by any known method, such as mixing an aminopyridine or a pharmaceutically acceptable salt thereof with a suitable carrier or diluent and filling the proper amount of the mixture in capsules. Carriers and diluents include, but are not limited to, inert powdered substances such as starch of many different kinds, powdered cellulose, especially crystalline and microcrystalline cellulose, sugars such as fructose, mannitol and sucrose, grain flours and similar edible powders.

[00120] Tablets can be prepared by known methods such as direct compression, by wet granulation, or by dry granulation. Their formulations usually incorporate diluents, binders, lubricants and disintegrators as well as the compound. Typical diluents include, for example, various types of starch, lactose, mannitol, kaolin, calcium phosphate or sulfate, inorganic salts such as sodium chloride and powdered sugar. Powdered cellulose derivatives are also useful. Typical tablet binders are substances such as starch, gelatin and sugars such as lactose, fructose, glucose and the like. Natural and synthetic gums are also convenient, including acacia, alginates, methylcellulose, polyvinylpyrrolidine and the like. Polyethylene glycol, ethylcellulose and waxes can also serve as binders.

[00121] In a preferred embodiment, the pharmaceutical composition is a sustained release tablet or capsule of 4-AP.

5.6 Combination treatments

[00122] In a specific embodiment, one can combine an aminopyridine or a pharmaceutically acceptable salt thereof with one or more other agents and/or physical or occupational therapies in concomitant therapy for the treatment of a patient with Parkinson's disease (PD). Concomitant administration can be concurrently, simultaneously, or sequentially (before or after). In a specific embodiment, concurrent administration can be over the same treatment period, e.g., on the same day, during the same week, or during the same two-week period, the same month, etc. In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient concomitantly with one or more additional drugs or therapy. In a specific embodiment, an aminopyridine or a pharmaceutically acceptable salt thereof is administered concomitantly with another drug or drugs effective for the impairment associated with PD. In certain embodiments, the drug(s) administered concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a dopaminergic agent, an anticholinergic agent, amantadine, or an adenosine A ₂ A receptor antagonist. In some

embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a dopamine precursor (e.g., levodopa). In one embodiment, the dopaminergic agent used concomitantly with an aminopyridine or a

pharmaceutically acceptable salt thereof is levodopa. In some embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a dopamine agonist (e.g., apomorphine, bromocriptine, pramipexole, roprinirole or rotigotine). In some embodiments, the dopaminergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is a drug that inhibits dopamine metabolism (e.g., MAO-B inhibitor, or a COMT inhibitor). The MAO-B inhibitor can be selegiline, rasagiline or zydis selegiline HC1. The COMT inhibitor can be entacapone or tolcapone. In some

embodiments, the anticholinergic agent used concomitantly with an aminopyridine or a pharmaceutically acceptable salt thereof is trihexyphenidyl, benztropine or ethopropazine.

[00123] In particular embodiments, the combination of an aminopyridine or a pharmaceutically acceptable salt thereof and one, two or more additional drug(s) is a fixed dose combination. For example, an aminopyridine or a pharmaceutically acceptable salt thereof and one or more additional drug(s) can be formulated in one composition, such as a pill, a tablet or a capsule. In other embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient concomitantly (e.g., at the same time, before or after) with physical therapy, occupational therapy, or speech therapy. In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient with PD who uses an assistive device (e.g., cane crutches, or a wheeled walker). In a specific embodiment, the aminopyridine (or salt thereof) and other drug or therapy is administered at the same doctor's visit, or within 1, 2, 3, 4, 5, 6, or 12 hours, or within 1, 2, 3, 4, 5, 6, or 7 days, of each other. [00124] In yet other embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient without an additional drug or therapy for PD, or without one or more of additional treatments for PD (such as those described above). In certain embodiments, treatment in accordance with the invention (either with or without use of an additional drug or therapy), is more effective than treatment with another drug or therapy known to be used for the treatment of PD.

[00125] Long term levodopa therapy is often accompanied by dyskinesias, which are sudden, involuntary movements. Additionally, an "on-of ' effect develops with long term levodopa therapy, wherein the patient experiences normal movement during "on" times, and reverts to PD-related motor impairment during "off times. In one embodiment, the methods described herein improve dyskinesia symptoms associated with levodopa treatment. In another embodiment, "on" times are increased in patients taking levodopa while being treated in accordance with the methods described herein. In yet another embodiment, treatment of patients on levodopa therapy with an aminopyridine (or salt thereof) using the methods described herein decreases the necessary levodopa dosage in comparison with levodopa therapy alone. In a specific embodiment, dalfampridine-ER produces at least a 20% increase in walking speed and/or stride length in patients with Parkinson's disease while on dopaminergic medication.

[00126] Surgical procedures such as pallidotomy, thalamotomy and deep brain stimulation (DBS) are also used to treat motor impairments in Parkinson's disease patients. In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient with PD before, during and/or after pallidotomy, thalamotomy or DBS.

[00127] In some embodiments, an aminopyridine or a pharmaceutically acceptable salt thereof is administered to a patient concomitantly with Occupational or Physical Therapy. In other embodiments, a patient treated in accordance with the methods described herein does not concomitantly receive Occupational or Physical Therapy.

[00128] In certain embodiments, treatment in accordance with the invention (either with or without use of another drug, surgery or therapy) is more effective than such other drug, surgery or therapy alone. 6. EXAMPLES

6.1 Example 1: Evaluation of Gait Impairment in Parkinson's disease

6.1.1 Study Objective

6.1.1.1. Primary Objective

[00129] The primary objective of this study is to evaluate the efficacy of dalfampridine-ER 10 mg (i.e., a sustained release formulation of 10 mg 4-aminopyridine) for walking impairment in Parkinson's disease. The primary outcome measure will be the change in walking velocity and stride length as measured with a 3 dimensional gait analysis system.

6.1.1.2. Secondary Objective

[00130] The secondary objective of this study is to evaluate the efficacy of dalfampridine-ER 10 mg (i.e., a sustained release formulation of 10 mg 4-aminopyridine) on other outcome measures. The exploratory outcome measures that will be studied are: UPDRS score, TUG score, FOGQ and Timed 25 -foot Walk.

6.1.1.3. Additional Objectives

[00131] Monitoring safety and tolerability in Parkinson's patients treated with dalfampridine-ER.

6.1.2 Study Design

6.1.2.1. Overview

[00132] This is a single center, double-blind, randomized, crossover trial. Subjects will be randomly assigned to dalfampridine-ER (10 mg p.o. bid) or placebo for a period of 4 weeks and crossed over after a 2 week washout period. Total duration of the study will be 10 weeks for each patient so that each patient will receive placebo and the medication (see Figure 2).

6.1.2.2. Discussion of Study Design

6.1.2.2.1 Rationale for Study

[00133] Walking velocity and stride length will be examined in patients with

Parkinson's disease that are administered dalfampridine-ER. Assessment of the change in walking function is accomplished via 3D motion capture, with walking speed and stride length as the primary outcome measures. This method will assure high sensitivity and will help reduce the number of patients needed to treat. The crossover design minimizes the number of patients to treat. Each patient will serve as its own control so no healthy subjects are required for the study. The half life of the drug is around 6 hours, so that 2 weeks washout is considered sufficient. For symptomatic benefit, 4 weeks of treatment was deemed to be sufficient to detect changes.

[00134] The specific mean velocity of patients with PD while "ON" is 101.3 cm/s

± 20.84 while the stride length is 102.18 cm ± 18.57. The 3D gait analysis system will allow objective quantification of walking and will be sensitive enough to detect small changes in the walking parameters. The 3 -dimensional gait analysis is carried out using the Peak Motus system, which uses 8 cameras to capture the coordinates of moving points. The points are detected using optical sensors attached to a person's joints at specified locations. With these coordinates, accurate biomechanical data are produced, including velocities, center of mass, distances, and angles. These measures enable the calculation of other measures, such as step length, symmetry of posture, and ground clearance, among others.

[00135] The secondary objective will be to examine the effect on clinical measures of walking such as Timed Up and Go Test, Timed 25 -Foot Walk, Freezing of Gait Questionnaire and on Unified Parkinson Disease Rating Scale. The incidence of adverse effects and tolerability of dalfampridine-ER will also be part of secondary objectives.

[00136] The walking velocity and stride length are the primary efficacy measures and are able to detect subtle changes and with a reasonable patient number (20). A larger number of patients would be required for the study if the primary efficacy outcome were TUG (30).

6.1.2.2.2 Dosage

[00137] Patients will receive dalfampridine-ER tablets of 10 mg by mouth twice daily.

[00138] The choice of 4 weeks of treatment is based on both efficacy and tolerability criteria. The assumption is that symptomatic effects will be detected early, since the half-life is around 6 hours; however, in order to have enough data to show safety and tolerability the duration of treatment is 4 weeks. [00139] Post-treatment follow-up will be done first day of treatment. Patients will be evaluated in the office 3 hours after treatment to monitor side effects and symptomatic benefit. Peak dose is expected about 4 hours. Telephone follow up and scheduled visits will monitor the effects and tolerability of dalfampridine-ER. If side effects are reported, patients will be seen immediately in clinic.

6.1.3 Study Population

6.1.3.1. Subject Numbers

[00140] A total of 20 patients will be recruited to complete the study. Patients will be randomized to 2 arms: placebo versus dalfampridine-ER. The population from which these subjects will be selected are PD patients of both genders age 45-80. Women of childbearing potential will be excluded. See 6.1.9 for justification of the selected sample sizes.

6.1.3.2. Inclusion Criteria

• Patients with idiopathic PD with Hoehn and Yahr (H & Y) Stage 1-3 and with gait freezing or postural instability.

• Patients should be on stable dosage dopamine agonist/levodopa, and expected to remain on the same dosage of treatment for the duration of study.

• Age less than 80, onset of disease at age more than 45.

• Able to give consent.

6.1.3.3. Exclusion Criteria

• Past medical history of seizures.

• History of renal insufficiency.

• History of cardiac arrhythmia.

• Previous DBS (Deep Brain Stimulation).

• Severe arthritis.

• Women of childbearing potential.

• Cognitive impairment as determined by MOCA.

• Age more than 80.

• PD patients stage 4 H & Y. • PD patient with recent introduction of dopamine agonist or IMAO B.

• PD patients participating in other studies.

6.1.3.4. Discussion of Subject Characteristics

[00141] Patient with PD stage 1-3 on stable dopaminergic therapy and with gait dysfunction are the ideal candidates for this study. Gait dysfunction will be assessed using FOG questionnaire. Age more than 45 at onset of disease is to avoid young onset PD cases. PD patients with age more than 80 are excluded due to possibility of dizziness and associated comorbidities. Subjects that may have gait impairment due to other causes will be excluded (i.e. arthritis, congestive heart failure). Patients that are required to use an assistive device will be allowed to participate but will be required to use the device in all visits. Patients will take their medication as usual and clinical tests will be done while on medication.

6.1.3.5. Warnings/Precautions

[00142] The risk of seizures increases as the dose of dalfampridine-ER increases.

It is also suspected that drug plasma levels in patients with mild renal impairment (CrCl, 51-80 mL/minute) might be associated with an increased risk of seizures as well. Therefore, renal function and seizure risk must be assessed before dalfampridine therapy is begun. If seizures occur while the patient is taking dalfampridine, the drug should be discontinued and not reinitiated.

[00143] No children, pregnant or potential childbearing women will participate in the study.

6.1.4 Study Procedures

[00144] 3D Gait analysis will be performed using an 8-camera 30 motion capture system (Peak Motus® Software, Peak Performance, Centennial, CO). A physical therapist experienced in computerized gait analysis systems will run the study. An array of 21 reflective markers will be placed bilaterally at the lateral malleoli, 5th ray metatarsal-phalangeal joints, heels, lateral knee joints, greater trochanters, anterior superior iliac spines, shoulders, elbows, and wrists as well as at C7, T10, and the sacrum. For each walking test session, subjects will walk five times across a 6-m walkway at their preferred walking speed; subjects will be allowed to rest between walking tests. Subjects will use assistive devices as required during testing.

[00145] Unified Parkinson's disease rating Scale (UPDRS) will be performed by a

Movement Disorder Specialist. UPDRS contains 4 sections. Part 1 assesses the non-motor aspects of daily living, part 2 motor aspects of daily living, part 3 is a motor examination of PD patient and part 4 quantifies the presence of motor complications like dyskinesias, fluctuations or dystonia.

[00146] Timed Up and go test (TUG) is a mobility test that is used to measure the basic mobility skills of people who are elderly or have neurological conditions. It includes a sit- to-stand component as well as walking 3 m, turning, and returning to the chair. People perform these tasks using regular footwear and customary walking aids. The measured outcome is the time in seconds to complete the entire sequence. Five measurements will be performed and mean time of the best 3 will be recorded.

[00147] Timed 25-foot walk test (T25FW) is a functional walking assessment that measures the time required for the patient to walk 25 feet. Five measurements will be performed and the 3 best measurements will be recorded.

[00148] Freezing of gait Questionnaire (FOGQ), is a clinician administered patient-reported rating scale that has been validated in patients with PD and consists of 16 items regarding gait and falls.

[00149] The Montreal Cognitive Assessment (MoCA) is a brief screening instrument for MCI (mild cognitive impairment) and dementia in Patients with Alzheimer and Parkinson's disease. The MoCA is divided into 7 subscores: visuospatial/executive (5 points); naming (3 points); memory (5 points for delayed recall); attention (6 points); language (3 points); abstraction (2 points); and orientation (6 points). One point is added if the subject has < 12 years of education.

6.1.4.1. Schedule of Activities

[00150] Screening visit is the initial visit where eligibility is determined based on the inclusion and exclusion criteria. Walking analysis and clinical questionnaires are performed during four scheduled visits. See Table 1. Table 1

Screening Visit 1 Visit2 Visit 3 Visit4 Unscheduled visit

-2 0 4 6 10

Informed consent X

General physical exam X X

Neurological exam X X

Inclusion/exclusion criteria X

Vitals and weight X X X X X X

Blood sample/urine sample X X X

PD staging X

MOCA X

3D Gait analysis X X X X

TUG test X X X X X

T25FW X X X X X

UPDRS X X X X X

FOGQ X X X X X

Adverse experience X X

information.

Diary card X

Dispense drug X X

TUG- Timed Up and Go Test T25FW- Timed 25-Foot Walk

FOGQ- Freezing of Gait Questionnaire MOCA- Montreal Cognitive Assessment

UPDRS- Unified Parkinson's Disease Rating Scale

6.1.4.2. Screening Visit (~2 weeks)

• The following activities will be conducted at screening visit:

• Sign informed consent. • History and physical examination- a complete history and physical exam will be performed by a movement disorder specialist.

• Inclusion/exclusion criteria will be reviewed by MD.

• Vital signs and weight measurements.

• Parkinson's disease staging.

• UPDRS.

• FOGQ.

• TUG.

• T25FW.

• Biological sample collection (urine and blood).

6.1.4.3. Visit 01 (time 0)

• Patient will take his usual medication as usual and will have all the clinical scales administered while "ON."

• UPDRS.

• TUG.

• T25FW.

• FOGQ.

• 3D gait analysis.

• Dispense medication: First dose of medication will be administered while under direct supervision of physician. Dalfampridine-ER 10 mg or placebo will be dispensed after the walking clinical assessments are done. Due to safety reasons patients will be monitored in the office for three hours. Side effects such as dizziness or worsening of tremors will be monitored. Vital signs will be monitored pre and post medication administration.

• 3 hours after medication administration the walking clinical scales will be re- administered: 3D Gait Analysis, UPDRS, TUG, and T25FW will be performed.

• A diary card to register any adverse events will be given to the patient.

6.1.4.4. Visit 02 (4 weeks) • Vital signs and weight measurement.

• UPDRS.

• TUG.

• T25FW.

• FOGQ.

• 3D gait analysis.

• Biological sample collection.

• Adverse experience information will be collected.

6.1.4.5. Visit 03 (6 weeks)

• Vital signs and weight measurement.

• UPDRS.

• TUG.

• T25FW.

• FOGQ.

• 3D gait analysis.

• Dispense medication: First dose of medication will be administered while under direct supervision of physician. Dalfampridine-ER 10 mg or placebo will be dispensed after the walking clinical assessments are done. Due to safety reasons patients will be monitored in the office for three hours. Side effects such as dizziness or worsening of tremors will be monitored. Vital signs will be monitored pre and post medication administration.

• 3 hours after medication administration the walking clinical scales will be re- administered: 3D Gait Analysis, UPDRS, TUG, and T25FW will be performed.

6.1.4.6. Visit 04-Final Visit (10 weeks)

• Vital signs and weight measurement.

• UPDRS.

• TUG.

• T25FW. • FOGQ.

• 3D gait analysis.

• Biological sample collection.

• Adverse experience information will be collected.

6.1.4.7. Unscheduled Visits

[00151] An unscheduled visit may be performed at any time during the study at the subject's request or as deemed necessary by the Principal Investigator. An unscheduled visit can occur if patient experiences side effects. The date and reason for the unscheduled visit will be recorded in the source documentation.

6.1.5 Assessments

6.1.5.1. Efficacy Assessments

[00152] Walking velocity and stride length will be measured 5 times via 30 motion capture with Peak Motus system in the gait laboratory. In PD patients mean walking velocity is 101.3 cm/s ± 20.84 while in normal subjects the velocity is 127.05 cm/s ± 16.48. For the stride length PD patients mean value is 102.18 cm ± 18.57, while controls have an average of 131.32 cm ± 13.18. The best 3 recordings will be used for quantification of effect of medication.

[00153] TUG will be measured using a stop watch. For healthy subjects mean value of TUG is 9.52 sec with SD (standard deviation) of 1.38 while for Parkinson's disease patients, the mean value of TUG is 13.83 sec with SD of 4.41. The best 3 recordings out of 5 measurements will be used for quantification.

[00154] Timed 25-foot walk test (T25FW) is a functional walking assessment that measures the time required for the patient to walk 25 feet. Five measurements will be performed and the 3 best measurements will be recorded.

[00155] Freezing of gait Questionnaire (FOGQ), will be administered by the clinical coordinator. It consists of 16 items regarding gait and falls and is reported as a score from 0-16.

[00156] Unified Parkinson's disease rating Scale (UPDRS) will be performed by a

Movement Disorder Specialist. UPDRS contains 4 sections. Part 1 assesses the non-motor aspects of daily living, part 2 motor aspects of daily living, part 3 is a motor examination of PD patient and part 4 quantifies the presence of motor complications like dyskinesias, fluctuations or dystonia.

6.1.5.2. Medical History & Physical/Neurological Examination

[00157] Will be performed by movement disorder specialists. Vital signs will be performed at each visit by Clinical Coordinator.

6.1.5.3. Blood Sample Collection

[00158] Will be performed by clinical trial coordinator. Sample will be stored for further testing.

6.1.5.4. Other Assessments

[00159] MoCA: The Montreal Cognitive Assessment (MoCA) is a brief screening instrument for mild cognitive impairment and will be performed by a Movement Disorder Specialist. The MoCA is divided into 7 sub-scores: visuospatial/executive (5 points); naming (3 points); memory (5 points for delayed recall); attention (6 points); language (3 points);

abstraction (2 points); and orientation (6 points).

6.1.5.5. Assessment of Subject Compliance

[00160] At each study visit, the Clinical Coordinator will assess the subject's compliance with the study requirements. This will include checks of protocol compliance, concomitant medication use, diary card data, and use of study drug in order to assess the reliability of subject-generated data. Subjects who fail to comply with the study requirements may be withdrawn from the study.

6.1.6 Concomitant Medications

6.1.6.1. Allowed Concomitant Medications

[00161] Patients are allowed to be taking simultaneously carbidopa, dopamine agonists or MAO-B inhibitors. Levodopa equivalent daily dosage (LEDD) will be calculated for each patient. 6.1.6.2. Disallowed Medications

[00162] Patients should not take other pyridine derivatives.

6.1.7 Study Drug Administration

6.1.7.1. Study Drug

[00163] Dalfampridine-ER is a potassium channel blocker, available in a 10 mg tablet strength. Each tablet contains 10 mg dalfampridine, formulated as an extended release tablet for twice-daily oral administration. Placebo pills will also be also provided.

6.1.7.2. Subject Number Assignment/Enrollment

[00164] Subjects will be assigned to treatment or placebo arm by computer randomization. Pre-assigned drug kits will be supplied.

6.1.7.3. Dosage of Study Drug

[00165] Patients will take 10 mg of dalfampridine-ER by mouth twice a day or placebo for four weeks. If a dosage is forgotten, the patient will not take an extra one in order to avoid risk of seizures.

6.1.8 Safety/ Adverse Experiences

6.1.8.1. Adverse Experience

[00166] An adverse experience is any symptom, sign, illness, or experience which develops or worsens during the course of the study, whether or not the event is considered related to study drug.

[00167] Possible adverse events to be considered are nausea, asthenia, headache, fatigue, insomnia, dizziness or worsening of tremors.

6.1.8.2. Serious Adverse Experiences

[00168] A serious adverse drug experience is defined as any adverse experience that occurs at any dose that results in any of the following outcomes: death; a life-threatening adverse experience; inpatient hospitalization, a persistent or significant disability/incapacity.

[00169] The predicted effects of overdosage with dalfampridine-ER is possibility of seizure event. Patients will be instructed to avoid concomitant usage of alcohol or other aminopyridine derivatives. If patient skips a dosage, they will be instructed not to take an extra pill in order to avoid overdosage.

6.1.9 Statistical Analysis

[00170] The statistical power estimate is based on a range of sample sizes, effect sizes (defined as mean difference between dalfampridine-ER and placebo groups divided by the square root of the within mean square error), at a 0.05 significance level with a two-sided t test. A total sample size of 20 PD patients will achieve at least 80% power to uncover an effect size of 0.94 at a significance level of 0.05 for a two-sided test. This effect size is corresponding to a mean difference of 14 cm in stride length (14% change) given that the square root of the within mean square error is 15.

[00171] The same effect size corresponds to a difference of 19% in velocity assuming a standard deviation of 20. The power analysis is performed with PASS 2008

Software (NCSS, Kaysville, UT). For velocity an effect size of 19%>.

[00172] Estimated frequencies of adverse events, central tendency and variability for patient's demographic characteristics, T25FW, TUG and UPDRS score are used for the data analysis. Intent-to-treat (ITT) analysis is used to evaluate the effect of dalfampridine-ER on changes in T25FW, TUG and UPDRS score using mix-effects models that include both fixed and random subject-effects. All analyses are conducted using SAS (version 9.2, SAS Institute Inc., Cary, NC).

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6.2 Example 2: Evaluation of Gait Impairment in a Patient with Parkinson's Disease

[00173] In this example, the effect is reported of 4-aminopyridine (4-AP) on walking (walking speed and gait) in a patient with levodopa-resistant freezing of gait. The patient had improvement of freezing of gait, and increased stride length and velocity, effects that were long lasting.

[00174] The effect of 4-AP in a patient with Parkinson's disease-related freezing of gait was analyzed. The patient had signed an informed consent according to University of Miami regulations. The patient had been diagnosed with Parkinson's disease 19 years ago and had been doing relatively well with 600 mg of levodopa, selegiline and amantadine (MDS- UPDRS motor score-52). As the disease progressed, he had worsening of his walking difficulties and for the preceding 4 years significant freezing of gait (FOG) and unwanted acceleration in walking (i.e., festination). The FOG was unresponsive to levodopa and further augmentation was not possible due to somnolence. He was also unresponsive to dopaminergic agonists. His gait freezing episodes were present on a daily basis and interfered significantly with his daily activities. His freezing of gait questionnaire score was 16 while OFF levodopa and did not change in the ON state. For his freezing of gait, dopamine receptor agonists or dopamine augmentation have not been useful. Due to his severe freezing of gait, the patient was started on 4-AP 5 mg p.o. three times daily to evaluate the effects on walking and freezing of gait. At the time 4-AP was administered, the patient was only on levodopa and not on selegiline or amantidine.

[00175] Clinical measures of gait such as Timed Up and Go (TUG), Timed 25

Foot Walk (T25FW), Freezing of Gait Questionnaire (FOGQ) and MDS-UPDRS were assessed pretreatment, and 2 hours, 48 hours, and 30 days after the initiation of treatment. After 2 days of treatment, the patient reported significant improvement of FOG that persisted at 90 days into the treatment. The measures were repeated pre and post 4-AP 90 days into the treatment. For the 90 days pre and post 4-AP measurements, the patient was instructed to stop the 4-AP 3 days in advance and come for measurements and the patient was ON levodopa at the time of

measurement; after 2 hours of 4-AP treatment, the measurements were repeated. Spatial- temporal gait parameters were recorded using wireless sensors (APDM Inc., Portland) attached to ankles. All the assessments were done while ON levodopa.

[00176] The patient reported significant improvement in the freezing of gait throughout the course of treatment. Axial MDS-UPDRS and freezing of gait scores improved significantly at 2 hours and 48 hours after treatment initiation, whereas the effects on stride length and velocity were not seen until later during treatment (see Table 2). His FOG score improved 50 % (from 16 points pretreatment to 8 post administration), and the axial UPDRS from 10 points to 3. The effects on FOG have been stable over 30 days and his FOG returned after 4-AP was briefly interrupted at day 90.

Table 2*

Pre 4-AP 2h post 48h post 30 days 90 days 90 days

4-AP 4-AP post 4- pre 4-AP post 4- AP AP

FOGQ 16 16 8 10 9 9 —

Motor 52 (10) 40 (7) 35 (3) 34 (4) 46 (10) 31 (5)

UPDRS

(axial)

TUG (s) 16.7 +/- 14.7 +/- 14.0 +/- 12.7 +/- 16.2 +/- 11.8 +/- p=0.0008

1.01 0.9 0.5 0.9 1.1 1.6

T25FW (s) 8.5 +/- 7.7 +/- 9.3 +/- 7.9 +/- 8.0 +/- 9.1 +/- P=0.15

0.4 0.7 1.5 0.1 0.4 0.7

Velocity 60.2 +/- 59.3 +/- 59.48 +/- 59.4 +/- 59.9 +/- 64.7 +/- P=0.0001 (% stature/s) 0.49 0.2 0.4 0.1 0.8

Stride 43.8 +/- 44.6 +/- 41.2 +/- 47.9 +/- 58.1 +/- 58.3 +/- P<0.0005 (% stature) 0.7 1.7 0.5 1.0 0.6 0.9

CV stride 11.6 +/- 10.6 +/- 6.3 +/- 8.6 +/- 9.1 +/- 5.9 +/- p=0.11 time (%) 4.6 3.2 0.57 2.3 1.3 0.4

CV DLS (%) 36.3 +/- 28.6 +/- 20.6 +/- 24.6 +/- 26 +/- 28.8 +/- p=0.011

0.5 7.3 3.2 1.1 3.9 4.3

Cadence 142 +/- 136 +/- 132 +/- 120 +/- 123 +/- 133 +/- P=0.0008 (steps/min) 4.5 3.4 1.4 8.8 5.4 1.7

*The spatio-temporal gait parameters of the patient were measured pretreatment, 2 hours after administration of 4-AP, after 48 hours, at 30 days and repeated at 90 days pre and post 4-AP. Axial UPDRS score is presented in parentheses. Velocity and Stride Length are normalized to the patient's height and expressed as percentage.

FOGQ - Freezing of Gait Questionnaire TUG - Timed Up and Go Test

T25FW - Timed 25-Foot Walk CV - Coefficient of Variation

DLS - Double Limb Support UPDRS - Unifed Parkinson's Disease Rating Scale

[00177] The TUG test showed significant improvement from 16.7 s at baseline to 14.0 s +/-0.5 48 hours after 4-AP administration. The effects on TUG lasted through the course of treatment at day 30 (12.7 s +/- 0.9) and upon discontinuation of 4-AP at day 90 returned to 16.2 s +/- 1.1 (see Figure 3 A). After treatment re-initiation at day 90, TUG improved significantly (11.8 s +/-1.6). Velocity (normalized by height) increased slightly from 60.2 +/-0.49 to 64.7 +/-0.8 at day 90, whereas stride length increased from 43.8 +/-0.7 to 58.3 +/- 0.9 (Figure 3B). Also, turning time decreased from 3.73 s +/-0.5 to 2.93 s +/-0.36.

[00178] The favorable effects on spatial gait kinematics were associated with an improvement in gait variability as reflected by a decrease in the coefficient of variation of double limb support (DLS) from 36.3 to 28.8%, and a decrease in stride time coefficient of variability from 11.6 to 5.9% (see Table 2).

[00179] 4-AP was tolerated well with no side effects and the patient continues to have benefits 6 months after the initiation of treatment. The significant effects on TUG test are likely explained by improvement in FOG and decrease in turning time. The effect on T25FW test was negligible since patient major difficulties were with gait initiation and turning and not with walking on a straight line. The beneficial effects on velocity and stride that are seen at 90 days are associated with improvement in gait variability, suggesting that 4-AP may modulate the gait pattern.

[00180] These results suggest that 4-AP may have a short term effect, seen in the patient as improvement in FOG and TUG, but also a long term effect that is manifested as an increase in stride length and a reduction in gait variability.

6.2.1 References

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Incorporation by reference

[00181] Various references such as patents, patent applications, and publications are cited herein, the disclosures of which are hereby incorporated by reference herein in their entireties.