SPECTRUM DISORDER The invention relates to the N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5- g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide or a pharmaceutically acceptable salt thereof, for its use as medicament for the treatment of autism spectrum disorder.

Patent application WO 201 1 /027289 discloses chromone derivatives, a process for their preparation and their therapeutic applications for the treatment of neurological or psychiatric diseases. The chromone derivatives according to WO 201 1 /027289 are dopamine D3 receptor partial agonists or antagonists.

Notably, WO 201 1 /027289 discloses the N-(3-{4-[4-(8-Oxo-8H- [1 ,3]dioxolo[4,5-g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)- methanesulfonamide (Example N°21 of WO 201 1 /027289) corresponding to formula 1 .

Formula 1

Among the diseases to be treated by the chromone derivatives, WO 201 1 /027289 claims Parkinson's disease, psychosis, schizophrenia, dyskinesias associated with Parkinson's disease, cognitive deficiency optionally associated with age or with Alzheimer's disease, mood disorder, essential tremor, anxiety, depression, bipolar disorder, sexual impotence, premature ejaculation, alcoholism and nicotine addiction. Notably, WO201 1 /027289 does not disclose nor claim neurodevelopmental disorders. The neurodevelopmental disorders are a group of conditions with onset in the developmental period. These disorders typically manifest in childhood and are characterized by developmental deficits that produce impairment of personal, social, academic, or occupational functioning. The range of disabilities varies from very specific limitations of learning or control of executive functions to global impairments of social skills or intelligence.

Among neurodevelopmental disorders, autism has been characterized as an infantile trouble distinct from psychoses and its signs and symptoms described by Kanner in 1943 (L. Kanner "Autistic Disturbances of Affective Contact", Nervous Child 2:217-50, 1943), which includes various troubles in behaviour and skills. Autism included the typical infantile autism or Kanner's autism, Asperger's syndrome, which preserves language and cognitive functions and pervasive developmental disorder, not otherwise specified (commonly abbreviated as PDD-NOS), which was diagnosed when the full set of criteria for autism or Asperger syndrome were not met. Other classifications, like the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) from the World Health organization, includes even more subcategories. The variability of symptoms and presentations of autism among those various diagnostic categories made it difficult to comprehend to which particular symptom a therapeutic treatment was addressed.

Very recently however, the diagnosis of autism has markedly changed to recognize that social deficits distinguish autism and related disorders from other neurodevelopmental disorders (Rapin I, Tuchman RF. Autism: definition, neurobiology, screening, diagnosis. Pediatr Clin North Am. 2008;55(5):1 129- 46) and to unify the diagnosis under the unique name of Autism Spectrum Disorder (ASD). According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5, American Psychiatric Association, American Psychiatric Publishing, Washington D.C., 2013), ASD is characterized by persistent deficits in social communication and social interaction across multiple contexts, including deficits in social reciprocity, non verbal communicative behaviors used for social interaction, and skills in developing, maintaining and understanding relationships. In addition to the social communication deficits, the diagnosis of autism spectrum disorder requires the presence of restricted, repetitive patterns of behaviors, interests, or activities.

Within the diagnosis of ASD, individual clinical characteristics are noted through the use of specifiers that describe the autistic symptoms and their severity. Thus, according to DSM-5, the disorder is diagnosed with the following diagnostic criteria:

A: Social Communication and Interaction across multiple contexts (all 3 required).

· deficits in social-emotional reciprocity.

• deficits in nonverbal communicative behaviors used for social interaction.

• deficits in developing and maintaining relationships.

B: Restricted, Repetitive Behavior (any 2 required).

· stereotyped or repetitive speech, motor movements, or use of objects.

• excessive adherence to routines, ritualized patterns of verbal or nonverbal behaviors, or excessive resistance to change.

• highly restricted, fixated interests that are abnormal in intensity of focus.

• hyper-or hypo-reactivity to sensory input or unusual interest in sensory aspect of environment.

C: Symptoms must be present in the early developmental period.

D: Symptoms cause clinically significant impairment of social, occupational, or other important areas of current functioning.

E: These disturbances are not better explained by intellectual disability or global developmental delay.

ASD is a highly inherited neuropsychiatric disorder: the concordance rate reaches up to 90% in monozygotic twins and 10% in dizygotic twins (reviewed in Won et al., Front. Mol. Neurosci. 2013, vol 6, art 19). However, ASD is an etiologically heterogeneous disorder in that no single genetic mutation accounts for more than 1 -2% of cases (Abrahams et al ., Nat. Rev. Genet. 2008, vol 9, p 341 -355). Thus far, linkage and candidate-gene analyses, genome-wide association studies (GWAS), and assessments of chromosomal variations have uncovered a wide range of genes with predisposing mutations and polymorphisms associated with ASD (Persico et al ., Behav. Brain Res. 2013, vol 251 , p 95-1 12). None of these studies have identified the DRD3 as a susceptibility gene for ASD.

In 2009, de Krom and colleagues performed a genetic association study of 1 ,536 Single Nucleotide Polymorphisms (SNPs) present in 132 candidate genes in a sample of 144 patients with ASD and 404 control individuals (de Krom et al ., Biol. Psychiatr., 2009, vol 65, p 625-630). They found 31 single nucleotide polymorphisms positively associated at a P value lower than 0.01 , which were tested in a second sample of 128 patients with ASD and 124 control individuals. Only the single nucleotide polymorphism rs167771 was found positively associated in the two ASD samples and in a joint statistical analysis. An association, which was not confirmed following statistical correction for multiple testing, was also found between the risk allele of rs167771 and a decreased risk of repetitive behaviour in patients with ASD, but not of other ASD symptomatic domains (Staal et al., J. Autism Dev. Disord. 2012, vol 42, p 885-888).

The single nucleotide polymorphism rs167771 is present in the second intron of the dopamine D3 receptor gene. The dopamine D3 receptor is almost exclusively expressed in the central nervous system, particularly in the ventral striatal area, a brain region that plays an important role in the control of emotions and cognition (Sokoloff et al., Nature 1990, vol 347, p 146-151 ). The dopamine D3 receptor exists in two allelic forms generated by a single nucleotide polymorphism named rs6280 (also known as CM033372 or Bah polymorphism) in the coding sequence, which leads to two amino acid sequences containing either a serine (Ser) or a glycine (Gly) residue at the 9 ^th position (Lannfelt et al., Psychiatric Genetics 1992, vol 2, p 249-256). The Gly/Gly allele is a gain-of-function allele, since it has a four times higher affinity for dopamine and is more responsive to dopamine than the Ser/Ser allele (Jeanneteau et al., Proc. Natl. Acad. Sci. USA 2006, vol 103, p 10753-10758). A therapeutic treatment based on intervention at the dopamine D3 receptor could be envisioned if the disorder to be treated is linked to either the gain-of- function (Gly/Gly allele) or loss-of-f unction (Ser/Ser allele). For instance, dopamine D3 receptor antagonists could be useful for treating a disorder linked to the Gly/Gly gain-of-function allele.

The e!Ensembl genetic database of the human genome (available at http://www.ensembl.org) indicates that the two single nucleotide polymorphisms rs167771 and rs6280 belong to the same contig NT_005612.16 of the assembly GRCh37.p10 and are separated by 14,540 base-pairs. Data from linkage disequilibrium tables (also available at http://www.ensembl .org), indicate partial linkage disequilibrium between rs167771 and rs6280, with r square values (Pritchard et al., Am. J. Hum. Genet, 2001 , vol 69, p 1 -14) ranging from 0.245 to 0.610 in different populations. This indicates that the genetic association of rs167771 in ASD does not formally imply a linkage of ASD to the functional single nucleotide polymorphism rs6280 in dopamine D3 receptor. Accordingly, in another study on a small sample of 50 patients, rs6280 was not found to be associated with ASD (Martineau et al., Dev Med Child Neurol, 1994, 36:688- 697).

There is no cure for ASD. Atypical antipsychotics, such as risperidone or aripiprazole, are approved by the US Food and Drugs Administration for the treatment of irritability associated with autistic disorder, including symptoms of aggression towards others, deliberate self-injury, temper tantrums and rapid mood changes, which do not belong to the core symptoms that define ASD. Adolescents and young adults with ASD are also prone to anxiety and depression, which can be treated with antidepressant drugs such as selective serotonin reuptake inhibitors. However, there is no approved treatment that targets the core symptoms ASD, i.e. deficits in social interactions and communication, and restricted interests.

Moreover, the genetic studies, are not conclusive and do not teach a method for treating ASD, especially the deficits in social interactions. The inventors surprisingly found that the N-(3-{4-[4-(8-Oxo-8H- [1 ,3]dioxolo[4,5-g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)- methanesulfonamide disclosed in WO 201 1 /027289 was of great benefit in an animal model that recapitulates core symptoms of ASD, which is based on prenatal exposure to valproate.

Valproic acid or its valproate salts, are anticonvulsivant drugs, e.g. Depakote®, used to treat epilepsy, a common and diverse set of chronic neurological disorders characterized by unprovoked seizures. Valproate is also used in the treatment of bipolar disorder, a psychiatric mood disorder presenting with episodes of an elevated or agitated mood known as mania (or hypomania, depending on the severity) alternating with episodes of depression. Teratogenic effects (abnormalities linked to neural tube closure) of valproate have been known for 30 years from retrospective studies. Cases of ASD were also found in children from mothers who had taken valproate during their pregnancy, which led to warning on valproate and ASD risk in child-bearing women. Recently, the valproate-associated risk was confirmed by prospective studies, indicating that there is a 10-fold increase in the risk of ASD (Tomson et al., Lancet Neurol. 2012, vol 1 1 , p 803-813; Bromley et al ., J. Neurol. Neurosurg. Psychiatry 20^, vol 84, p 637-643). Valproate is supposed to cause ASD by interfering with epigenetic mechanism driving closure of the neural tube during intrauterine development (Kataoka et al ., Int. J. Neuropsychopharmacol. 2013, vol 16, p 91 - 103).

In the ASD rat model, valproate is administered to pregnant females, at a determined embryonic day, typically the 12 ^th day, which corresponds to the time of neural tube closure in this species, and the offspring, when observed during infancy and adolescence, present with marked and specific behavioral abnormalities, accompanied by a few physical signs (reviewed in Roullet et al., Neurotoxicol. Teratol. 2013, vol 36, p 47-56). The valproate-induced behavioral abnormalities are strongly reminiscent of ASD symptoms and include:

• impairments of social behavior

• stereotyped/repetitive patterns of behavior • sensory and communication impairment.

In addition, the phenotype also incorporates morphological rearrangements typical of ASD, such as reduced number or density of neuronal dendritic spines in the prefrontal cortex (Bringas et al., Neuroscience 2013, vol 241 , p 170-187), which endows the valproate rat model with construct and face validities for a pathophysiological animal model of ASD.

In order to assess the potential of N-(3-{4-[4-(8-Oxo-8H-[1 ,3]dioxolo[4,5- g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide

hydrochloride, a potent dopamine D3 receptor antagonist (see Example 1 ) for treating ASD, the inventors have evaluated it in the ASD rat model (Example 2). As described in Example 2, the N-(3-{4-[4-(8-Oxo-8H-[1 ,3]dioxolo[4,5- g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide

hydrochloride was able to reverse social behavior deficit in prenatally valproate- exposed young rats administered as a single dose. The inventors thus showed that the said compound can be used to treat ASD.

As used above, the term "dopamine D3 receptor", "D3 receptor" or "DRD3" denotes a dopamine receptor sub-type chiefly expressed in the limbic system (Sokoloff P et al ., Nature 1990, vol 347, p 146-151 ). Dopamine D3 receptor is described in international patent application WO 91 /15513. As used above, the term "D3 receptor partial agonist" denotes a compound that forms a complex with dopamine D3 receptor and acts as a combined agonist- antagonist, that is to say it induces a physiological response of an intensity lower than that of the natural mediator, dopamine. In vitro, in a cell expressing dopamine D3 receptor, a dopamine D3 receptor partial agonist produces an active response the maximum intensity of which is lower than that produced by dopamine or by a full agonist, for example quinpirole (trans( - )-4aR- 4,4a,5,6,7,8,8a,9-octahydro-5-propyl-1 H(or 2H)pyrazolo[3,4g]quinoline). A dopamine D3 receptor partial agonist may also partially prevent the response produced by dopamine or other full agonists. As used above, the term "a dopamine D3 receptor antagonist" denotes a molecule that forms a complex with dopamine D3 receptor and is capable of preventing a response triggered by dopamine or an agonist thereof in a cell expressing dopamine D3 receptor.

As used here, the term "salts" denotes inorganic acid, organic acid, inorganic base or organic base addition salts of the compound of the present invention. As example, mention may be made of the salts derived from inorganic acids such as hydrochloric, hydrobromic, phosphoric, sulfuric acids, and those derived from organic acids such as acetic, trifluoroacetic, propionic, succinic, fumaric, malic, tartaric, citric, ascorbic, maleic, glutamic, benzoic, salicylic, toluenesulfonic, methanesulfonic, stearic, lactic acids. Preferably, the salts are pharmaceutically acceptable, that is to say, they are non-toxic for the patient to whom they are administered. The expression "pharmaceutically acceptable" refers to molecular entities and compositions that do not produce any adverse allergic effect or other undesirable reaction when administered to an animal or human. When used herein, the expression "pharmaceutically acceptable excipient" includes any diluent, adjuvant or excipient, such as preservative, filler disintegrator, wetting agent, emulsifier, dispersant, antibacterial or antifungal agent, or also agents that would allow intestinal and digestive absorption and resorption to be delayed. The use of those media or vectors is well known in the art. Except where the agent is chemically incompatible with the compound according to the invention, its use in pharmaceutical compositions containing the compound according to the invention is envisaged.

In the context of the invention, the term "treatment" as used herein means preventing or inhibiting the appearance or progression of the condition to which the term is applied, or of one or more symptoms of that condition. "Therapeutically active amount" means an amount of a the compound according to the invention that is effective in obtaining the desired therapeutic effect according to the invention. According to the invention, the term "patient" refers to a human affected or very susceptible to being affected by ASD.

According to the present invention, the compound (N-(3-{4-[4-(8-oxo-8H- [1 ,3]dioxolo[4,5-g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)- methanesulfonamide) or a pharmaceutically acceptable salt thereof, preferably hydrochloride, is used as a medicament for the treatment of ASD and notably the social interaction deficits.

The invention relates also to a treatment of ASD that comprises administering the compound (N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5-g]chromen- 7-yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide) or a pharmaceutically acceptable salt thereof in a therapeutically effective amount to a patient requiring treatment.

Moreover, the invention relates to pharmaceutical compositions containing the compound (N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5-g]chromen-7- yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide) or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient, for their use as medicament for the treatment of ASD, notably the social interaction deficits.

As another embodiment, the invention relates to pharmaceutical compositions combining the compound (N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5- g]chromen-7-yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide) or a pharmaceutically acceptable salt thereof, with other medications that are known to be used to treat ASD patients, and a pharmaceutically acceptable excipient, for their use as medicaments for the treatment of autism spectrum disorder, notably the social interaction deficits.

Preferably, the compound according to the invention is combined with a compound selected from the group consisting of memantine, amantadine, baclofen, R-baclofen, phenobam, acamprosate, bumetamide, carpipramine, oxytocin, vasopressin and mixtures thereof, and a pharmaceutically acceptable excipient.

The compositions according to the invention can be administered by the oral, transdermic, parenteral, nasal or rectal routes. The compositions can especially be administered by the oral route in an appropriate formulation. The dosages of the compound (N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5-g]chromen-7- yl)-butyl]-piperazin-1 -yl}-phenyl)-methanesulfonamide) in the compositions of the invention can be adjusted to obtain an amount of active substance that is effective in obtaining the desired therapeutic response for a composition peculiar to the method of administration. The dosage level chosen depends therefore on the desired therapeutic effect, the administration route, the desired duration of treatment and other factors like patient body weight. The dosages can be from 0.001 to 10 mg per kg of body weight. The preferred dosages are in the range of 0.05 to 2 mg per kg of body weight.

The following examples illustrate the invention without limiting the scope thereof.

Example 1

The N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5-g]chromen-7-yl)-butyl]- piperazin-1 -yl}-phenyl)-methanesulfonamide hydrochloride was evaluated in vitro as a dopamine D3 receptor ligand and modulator of the activity of that receptor in accordance with the invention in cells expressing human recombinant dopamine D3 receptor or human recombinant dopamine D2 receptor. The inhibition constant (Ki) was measured by inhibition of the binding of [ ³ H] spiperone as described by Cussac et al., in Naunyn-Schmiedeberg's Arch. Pharmacol. 2000, vol 361 , p 569-572. The inventors demonstrated that the compound according to the invention behaves as a potent dopamine D3 receptor ligand, with Ki values from 0.17 nanomole. liter ^"1 . This same compound exhibits a noticeable affinity for dopamine D2 receptor that is 71 times weaker.

Compound according to the invention was evaluated for its agonist, partial agonist, or antagonist activity at dopamine D3 receptor by using the MAP-kinase activity test on human recombinant dopamine D3 receptor (Cussac et al., Mol. Pharmacol. 1999, vol 56, p 1025-1030). The intrinsic activity of this compound was null, indicating that it is a full antagonist.

Example 2

The N-(3-{4-[4-(8-oxo-8H-[1 ,3]dioxolo[4,5-g]chromen-7-yl)-butyl]- piperazin-1 -yl}-phenyl)-methanesulfonamide hydrochloride was tested on social interaction of offspring of female rats which had been administered valproic acid as a sodium salt. The experimental settings of the valproic acid rat model of autism were adapted from published data (Dendrinos et al., Front. Integr. Neurosci. 201 1 , vol 5, art 68; Markram et al ., Neuropsychopharm. 2007, vol 33, p 901 -912; Schneider et al., Neuropsychopharm. 2005, vol 30, p 80-89).

Method:

Pregnant (embryonic day 8 max) female Sprague-Dawley rats [OFA (SD) Charles River Lyon, France] were quarantined for 4 days. Animals were group housed (2 per cage) in a full bottom cage (ML-H Cage, 370x235x180 mm, LxWxH; floor surface 870 cm ² ) in an environmentally controlled room (temperature 21 ± 1 °C; relative humidity 55 ± 5%) under a 1 2-h light/dark cycle (lights on at 07:00 AM) with food (A04, Safe, Augy, France) and filtered water (0.2 μιτι pore diameter) freely available. Until weaning of offspring, animals were changed only once per week in order to disturb them as little as possible. Environmental enrichment (nesting material) was provided.

On embryonic days 12 and 13 (E12-E13), females were weighed and received three intraperitoneal injections of 2.4 ml/kg of sodium valproate (NaVPA, 200 mg/kg). Sodium valproate was dissolved in 0.9% saline for a concentration of 83.3 mg/ml, pH 7.3. Control dams received three intraperitoneal injections of saline (2.4 ml/kg). After the third injection, females were individually housed in ML-H type cages and allowed to raise their litters. Offspring were weaned between 21 to 23 days postnatally.

One sodium valproate- or saline-exposed rat and an unfamiliar na ^' fve rat were placed in opposite corners of an arena (black arena 70 cm x 70 cm x 30 cm, L x I x H). Individual behavior related to social interaction such as following grooming, sniffing or biting the other rat as well as climbing over the other rat, initiated by the tested rat toward the unfamiliar rat were scored for a period of 10min.

Results:

The effects of acute administration of the compound according to the invention on social interaction behavior in the offspring of mothers treated with either saline or sodium valproate are summarized on Figure 1 .

The data represented are the mean ± the standard error of the mean for n=10 rats (5 females and 5 males).

The compound according to the invention had no significant effects on social interaction behavior in the offspring of saline-treated mothers.

At 0.63 mg/kg the compound according to the invention significantly reduced the social interaction deficits induced by prenatal exposure to sodium valproate. At 2.5 mg/kg the compound according to the invention completely reversed these deficits.

The compound according to the invention is considered as an interesting product to treat autism spectrum disorders and more particularly the deficit of social interactions.