Treating Fragile X Syndrome

Abstract

The present invention relates to a composition comprising ibudilast or a pharmaceutically acceptable salt thereof for use in the treatment of fragile X syndrome, wherein the composition does not include sulindac or a pharmaceutically acceptable salt thereof, or bumetanide or a pharmaceutically acceptable salt thereof.

Description

[Technical field]

[0001] The present invention relates to the use of ibudilast in the treatment of Fragile X Syndrome (FXS). [Background technology]

[0002] Fragile X syndrome (often referred to as fragile X) is the most common genetic cause of intellectual disability and the most common monogenic cause of autism. It affects approximately 1 in 4,000 males and 1 in 6,000 females worldwide.

[0003] There is a wide range of characteristics associated with fragile X, with males typically more affected than females. One of the major characteristics associated with fragile X syndrome is intellectual disability, such as difficulties with cognition, executive and language performance. Individuals with fragile X syndrome typically have social anxiety, characterized by social, emotional and communication difficulties associated with extreme shyness, poor eye contact and difficulties forming peer relationships. Fragile X syndrome is also associated with hyperactivity and disruptive behaviors, such as short attention span, distractibility, impulsivity, restlessness, hyperactivity and sensory problems. In addition, individuals with fragile X syndrome often suffer from epileptic seizures.

[0004] Fragile X syndrome results from mutations in a single gene called fragile X mental retardation gene 1 (FMR1). The 5'UTR of FMR1 contains CGG trinucleotide repeats that are polymorphic in the population. Once the number of repeats exceeds 200, promoter methylation is triggered, which in turn causes a lack of expression of the gene and translation of its encoded protein, fragile X mental retardation protein (FMRP). FMRP is an RNA-binding protein involved in various steps of mRNA metabolism, such as translational control (in neuronal cell bodies and dendritic spines) and RNA transport.

[0005] Currently, there are no effective therapies to treat fragile X syndrome. However, considerable efforts have been made to identify pharmacological targets to treat this disorder. In particular, fragile X syndrome has been a frequent target of drug repositioning and repurposing efforts in development. Many different criteria and methods have been applied to this task. In many cases, repurposing candidates have been identified primarily based on clinical pattern matching, whereas in other underlying diseases, mechanisms have been extensively studied to identify therapeutic targets, followed by thorough preclinical validation.

[0006] Overall, efforts to treat fragile X syndrome have led to some exciting possibilities, but despite many efforts there have been no conclusive successes, highlighting the need for new treatments.

[0007] Ibudilast is a phosphodiesterase inhibitor and is used as an anti-inflammatory agent. It is used in the treatment of asthma, stroke and multiple sclerosis. Ibudilast has the organizational name 2-methyl-1-(2-propan-2-ylpyrazolo[1,5-a]pyridin-3-yl)propan-1-one.

[0008] The present invention is a composition comprising ibudilast or a pharmaceutically acceptable salt thereof for use in treating fragile X syndrome, the composition not comprising sulindac or a pharmaceutically acceptable salt thereof, or bumetanide or a pharmaceutically acceptable salt thereof.As will be evident from the in vivo data presented below, ibudilast is effective in treating fragile X syndrome.

[0009] A first aspect of the invention is a composition comprising ibudilast or a pharma- ceutical acceptable salt thereof, wherein the composition does not include sulindac or a pharma- ceutical acceptable salt thereof, or bumetanide or a pharma- ceutical acceptable salt thereof, for use in the treatment of fragile X syndrome.

[0010] A second aspect of the present invention is the use of ibudilast, or a pharma- ceutical acceptable salt thereof, for the manufacture of a medicament for use in the treatment of fragile X syndrome, wherein the medicament does not comprise sulindac, or a pharma- ceutical acceptable salt thereof, or bumetanide, or a pharma- ceutical acceptable salt thereof.

[0011] A third aspect of the invention provides a method of treating fragile X syndrome, comprising administering to a patient a composition comprising ibudilast or a pharma- ceutical acceptable salt thereof, wherein the composition does not include sulindac or a pharma- ceutical acceptable salt thereof, or bumetanide or a pharma- ceutical acceptable salt thereof. [Brief description of the drawings]

[0012] [Figure 1] 1 shows results from an in vivo study of ibudilast. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Since fragile X is a syndrome, there are a number of different signs and symptoms in patients, including: intellectual disability (such as difficulties with cognition, executive and language performance, short-term memory, executive function, visual memory and visuospatial relationships); autism; social anxiety (i.e., difficulties with social interactions) (such as poor eye contact, averting gaze, long delays before initiating social interactions, and difficulties forming peer relationships); hyperactivity and repetitive behaviors (including very short attention spans, hypersensitivity to visual, auditory, tactile and olfactory stimuli, distractibility, impulsivity, restlessness and hyperactivity); disruptive behaviors (including mood swings, irritability, self-injury and aggression); obsessive-compulsive disorder (OCD); ophthalmological problems (such as strabismus); epileptic seizures; difficulties with working memory (including temporary storage of information while processing the same or other information); difficulties with phonological memory (or verbal working memory); and fragile X-associated premature ovarian insufficiency (FXPOI).

[0014] In the present invention, and as shown by the following in vivo data, ibudilast is used to treat one or more of the above symptoms, and is therefore an effective treatment for fragile X syndrome.Preferably, ibudilast is used to treat fragile X syndrome, where the patient shows typical symptoms of the syndrome, including social anxiety, hyperactivity, memory loss and / or disruptive behavior.More preferably, ibudilast is used to treat fragile X syndrome, where the patient shows hyperactivity, memory loss and / or disruptive behavior.

[0015] The term "hyperactivity" has its ordinary meaning in the art. Hyperactivity can include having a very short attention span, hypersensitivity to visual, auditory, tactile, and olfactory stimuli, being distractible, impulsive, restless, and / or overactive.

[0016] The term "social anxiety disorder" has its usual meaning in the art. It can also be referred to as social interaction difficulties or hyposociability. Social anxiety disorder can include poor eye contact, averting gaze, delayed initiation of social interactions, social avoidance or withdrawal, and difficulty forming peer relationships.

[0017] The term "memory loss" has its usual meaning in the art. It can also be called memory disorder. It refers to the inability to retain information either short-term or long-term. It can include difficulties with cognitive, executive and language performance, executive function, and visual memory. It can also include difficulties with working memory, also called short-term memory (i.e., temporary storage of information while processing the same or other information), and difficulties with phonological memory (or verbal working memory).

[0018] The term "disruptive behavior" has its ordinary meaning in the art. It may also include repetitive behavior. It may also include mood swings, irritability, self-injury and aggression.

[0019] As used herein, pharmaceutically acceptable salts are salts with pharmaceutically acceptable acids or bases.Pharmaceutically acceptable acids include both inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, diphosphoric acid, hydrobromic acid or nitric acid, and organic acids such as citric acid, fumaric acid, maleic acid, malic acid, ascorbic acid, succinic acid, tartaric acid, benzoic acid, acetic acid, methanesulfonic acid, ethanesulfonic acid, salicylic acid, stearic acid, benzenesulfonic acid or p-toluenesulfonic acid.Pharmaceutically acceptable bases include alkali metal (e.g., sodium or potassium) and alkaline earth metal (e.g., calcium or magnesium) hydroxides, and organic bases such as alkylamines, arylamines, or heterocyclic amines.

[0020] The present invention relates to a composition comprising ibudilast or a pharma- ceutically acceptable salt thereof, the composition being free of sulindac or a pharma- ceutically acceptable salt thereof, or bumetanide or a pharma- ceutically acceptable salt thereof, for use in the treatment of fragile X syndrome.

[0021] The composition according to the present invention does not contain sulindac or its pharma- ceutically acceptable salt.Sulindac is a nonsteroidal anti-inflammatory drug (NSAID).Sulindac shows anti-inflammatory, analgesic and antipyretic activity, and is therefore used in the treatment of acute and chronic inflammatory conditions, such as arthritis, shoulder bursitis and tendonitis.The composition according to the present invention does not contain any sulindac (i.e., 0% by weight of sulindac).

[0022] The compositions according to the invention do not comprise substances capable of regulating intracellular calcium concentrations, such as retinoic acid-related orphan receptor alpha (RORA) agonists, calcium channel inhibitors or inhibitors of solute transporter family 12 member 1, solute transporter family 12 member 1, 2, 4 or solute transporter family 12 member 1, 2, 4, 5, dihydropyridines, phenylalkylamines, benzothiazepines, indolazines, aminoglycosides, and 4-substituted derivatives of sulfamoylbenzoic acid (e.g., bumetanide, AqB007, AqB011, PF-2178, BUM13, BUM5 and bumepamine).

[0023] Specifically, the composition according to the present invention does not contain bumetanide or a pharma- ceutically acceptable salt thereof. Bumetanide is a diuretic typically used in the treatment of heart failure and swelling. The composition according to the present invention does not contain any bumetanide (i.e., 0% bumetanide by weight).

[0024] In another embodiment, the present invention relates to a composition comprising ibudilast or its pharma- ceutically acceptable salt for use in the treatment of fragile X syndrome, wherein ibudilast is the only active agent in the composition.The only active agent means that the composition does not contain other components that can be used in the treatment of fragile X syndrome, particularly components that can regulate intracellular calcium concentration.The composition may contain excipients such as fillers or binders.

[0025] In the present invention, the composition can be administered in various dosage forms. In one embodiment, the composition can be formulated in a form suitable for oral, rectal, parenteral, intranasal or transdermal administration, or administration by inhalation or suppository.

[0026] The compositions may be administered orally, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders, or granules. Preferably, the compositions are formulated so as to be suitable for oral administration (e.g., tablets and capsules).

[0027] The compositions can also be administered parenterally (either subcutaneously, intravenously, intramuscularly, intrasternally, transdermally, or by infusion techniques). Ibudilast can also be administered as a suppository.

[0028] The composition can also be administered by inhalation.The advantage of inhaled medicines is that they are delivered directly to areas with abundant blood supply, compared with many medicines taken by oral route.Thus, the alveoli have a huge surface area and abundant blood supply, and first-pass metabolism is bypassed, so absorption is very rapid.

[0029] The invention also provides an inhalation device containing the composition of the invention, typically a metered dose inhaler (MDI), which contains a pharma- ceutically acceptable chemical propellant to force the medicament out of the inhaler.

[0030] The composition can also be administered by intranasal administration. The highly permeable tissue of the nasal cavity is highly receptive to pharmaceuticals and absorbs them quickly and efficiently. Nasal drug delivery is less painful and invasive than injection, and causes less anxiety among patients. By this method, absorption is very rapid and first-pass metabolism is usually bypassed, thus reducing inter-patient variability. Furthermore, the present invention also provides an intranasal device containing the composition according to the present invention.

[0031] The composition can also be administered by transdermal administration.For topical delivery, transdermal and transmucosal patches, creams, ointments, jellies, solutions or suspensions can be used.Therefore, the present invention also provides a transdermal patch containing the composition.

[0032] The composition may also be administered by sublingual administration. Thus, the present invention also provides a sublingual tablet comprising the composition.

[0033] The compositions may also be formulated with agents that reduce degradation of the substance by processes other than the patient's normal metabolism, such as antibacterial agents or inhibitors of protease enzymes that may be present in the patient, or in commensals or parasites living on or within the patient, and which can degrade the compound.

[0034] The liquid dispersions for oral administration may be syrups, emulsions and suspensions.

[0035] Suspensions and emulsions may contain as a carrier, for example, natural gum, agar, sodium alginate, pectin, methylcellulose, carboxymethylcellulose, or polyvinyl alcohol. Suspensions or solutions for intramuscular injections may contain, together with the active compound, a pharma- ceutically acceptable carrier, for example, sterile water, olive oil, ethyl oleate, glycols, for example, propylene glycol, and, if desired, an appropriate amount of lidocaine hydrochloride.

[0036] The solutions for injection or infusion may contain as carrier, for example, sterile water or preferably they may be in the form of sterile, aqueous, isotonic saline solutions.

[0037] In one embodiment of the invention, the composition is administered in an amount effective to treat the symptoms of fragile X syndrome. Effective doses will depend on several factors, including age, sex, and weight, which will be apparent to one of skill in the art and can be determined by a medical professional.

[0038] In a preferred embodiment, the composition contains 10 mg to 300 mg of ibudilast, preferably 20 mg to 150 mg of ibudilast.

[0039] The compositions may be administered once daily, twice daily, three times daily, or four times daily.

[0040] In one embodiment of the present invention, the composition is administered at least once a day.Preferably, it is administered as one dose per day.Preferably, one dose per day contains 10 mg to 300 mg of ibudilast, preferably 20 mg to 150 mg of ibudilast.

[0041] In one embodiment of the invention, the composition is administered twice daily, preferably with each dose being between 20 mg and 100 mg of ibudilast, or between 20 mg and 50 mg of ibudilast.

[0042] Preferably, the dosing regimen is such that the total daily dose of ibudilast does not exceed 300 mg.

[0043] To treat fragile X syndrome, compositions containing ibudilast are used in chronic dosing regimens, i.e., chronic, long-term treatment.

[0044] The present invention also relates to the use of ibudilast or a pharma- ceutical acceptable salt thereof for the manufacture of a medicament for use in the treatment of fragile X syndrome, wherein the medicament does not include sulindac or a pharma- ceutical acceptable salt thereof, or bumetanide or a pharma- ceutical acceptable salt thereof. This embodiment of the present invention may have any of the preferred features described above.

[0045] The present invention also relates to a method for treating fragile X syndrome, comprising administering a composition comprising ibudilast or a pharmaceutically acceptable salt thereof to a patient, wherein the composition does not comprise sulindac or a pharmaceutically acceptable salt thereof, or bumetanide or a pharmaceutically acceptable salt thereof, and the patient is not administered bumetanide.Preferably, the patient is not administered a substance capable of regulating intracellular calcium concentration as described above.This embodiment of the present invention may have any of the preferred features described above.The method of administration may follow any of the routes described above.

[0046] For the avoidance of doubt, the present invention also encompasses prodrugs which react in vivo to provide the compounds of the present invention.

[0047] The following studies illustrate the invention.

[0048] Research 1 animal Fmr1 knockout 2 (Fmr1 KO2) mice were generated by deletion of the promoter and first exon of Fmr1. Fmr1 KO2, which is both protein null and mRNA null. In this study, we used Fmr1 KO2 and wild-type (WT) littermates generated in a C57BL / 6J background and repeatedly backcrossed to the C57BL / 6J background for more than eight generations.

[0049] Animal Containment Fmr1 KO2 mice were housed, 4–5 per cage group of the same genotype, in a temperature (21 ± 1 °C) and humidity controlled room with a 12-h light / dark cycle (lights on 7 am to 7 pm). Food and water were available ad libitum. Mice were housed in commercially available plastic cages and experiments were performed in accordance with the requirements of the UK Animals (Scientific Procedures) Act, 1986. The protocol was reviewed and approved by the IEB, University of Chile Institute Review Board. All experiments were performed by staff blinded to genotype and drug treatment. A separate investigator prepared and coded dosing solutions, assigned mice to study treatment groups, dosed animals, and collected behavioral data.

[0050] treatment group There were four treatment groups per compound in the study, with 10 male mice per treatment group (all 8 weeks old): Group 1: wild-type littermate mice treated with vehicle (WT-Veh), Group 2: Fmr1 KO2 mice treated with vehicle (KO-Veh), Group 3: Fmr1 KO2 mice treated with 12 mg / kg ibudilast (KO-Ibudilast).

[0051] Behavioral testing For the experiments, all mice were tested once in the same apparatus. Prior to testing, mice were placed in the apparatus for a few minutes before the experiment. The apparatus was cleaned with wet and dry tissues before testing each mouse. The aim was to create a low but constant background mouse odor for all experimental subjects. Testers were blinded to genotype and treatment during all tests and data analysis. Weight loss, hair loss, ambulation, eye opening, eye discharge, and general behavior were assessed. All signs indicated that all treatments were always well tolerated by Fmr1KO2 mice and WT littermates.

[0052] Open Field (hyperactivity) To test hyperactivity, an open-field apparatus was used. The apparatus was a 50 × 9 × 30 cm arena enclosed in gray PVC divided into a 10 × 10 cm grid. Mice were brought to the experimental room 5–20 min before testing. Mice were placed in a corner square facing the corner and observed for 3 min. The number of squares that the whole body entered (locomotor activity) was counted. The movement of the mice around the field was recorded for 3 min with a video tracking device (version NT4.0, Viewpoint).

[0053] Nesting Tests were performed in individual cages. Regular bedding covered the floor to a depth of 0.5 cm. Each cage was provided with a 5 cm square "Nestlet" (Ancare), compressed purified cotton. Mice were placed individually into the nesting cages 1 h before the dark period and results were assessed the following morning. Nest building was scored on a 5-point scale.

[0054] Score 1: The Nestlet was largely untouched (>90% unchanged).

[0055] Score 2: The Nestlet was partially torn (50-90% remained unchanged).

[0056] Score 3: Nestlets were mostly fragmented, but in many cases the nest location was not identifiable: <50% of the nestlets Score 4: Identifiable but flat nest <90% of the nestlet was torn and the material collected into a flat nest with walls less than 50% of its perimeter and higher than the height of the mouse curled up on its side.

[0057] Score 5: (Near) perfect nest: >90% of the Nestlet was torn, the nest was a crater and the walls were higher than the mouse body height in more than 50% of its perimeter.

[0058] Fear conditioning The dependent measure used in contextual fear conditioning was the freezing response following the pairing of an unconditioned stimulus (foot shock) with a conditioned stimulus in a specific context. Freezing is a species-specific response to fear and is defined as "the absence of movement other than breathing". It may last from a few seconds to several minutes, depending on the strength of the aversive stimulus, the number of presentations, and the degree of learning achieved by the subject. Testing involved placing the animal in a novel environment (dark chamber), delivering the aversive stimulus (a 1 s electric shock to the foot, 0.2 mA), and then removing it.

[0059] social interaction In the three-chamber sociability task, subject mice were assessed for their exploration of a novel social stimulus (novel mouse). The three-chamber social approach task monitors direct social approach behavior when subject mice are presented with a choice to spend time with either a novel mouse or an empty cup. Sociability is defined as the subject mouse spending more time in the chamber containing the mouse than in the empty chamber. Social novelty preference is defined as spending more time in the chamber with the novel mouse. The apparatus was a rectangular three-chamber box, with each chamber measuring 20 cm (length) x 40.5 cm (width) x 22 cm (height). The partition wall consisted of transparent perplex with small openings (10 cm width x 5 cm height) that allowed access to each chamber. The three-chamber task was lit from below (10 lux). Mice were allowed to freely explore the three-chamber apparatus over three 10-min trials. During a trial, one wire cup was placed upside down in one of the side chambers and a novel mouse was placed under another wire cup in the other side chamber (novel mouse stimulus), leaving the center chamber empty. The location of the novel mouse across trials was counterbalanced to minimize any potential confounds due to chamber location preferences. The time spent exploring the novel mouse was scored as the exploration ratio.

[0060] Statistical analysis of behavioral data Data were analyzed by one-way ANOVA with Dunnett's multiple comparison post-hoc test, where the WT Vehicle group was used as the reference and compared with all other groups. Interpretation of the statistics: NS: The mean of the WT group is not significantly different from the mean of any other group, and therefore the treatment brings the level to equal the WT (p>0.05). The mean of the WT group is statistically different from the mean of any other group, and therefore the treatment is not sufficient to equalize the WT level *P≦0.05 **P≦0.01 ***P≦0.001 ****P≦0.0001

[0061] conclusion As can be seen from Figure 1, treatment with a composition containing ibudilast completely rescued open field, nesting, fear conditioning, and sociability, demonstrating that a composition according to the present invention containing ibudilast is successful in treating fragile X syndrome.

Claims

1. 1. A pharmaceutical composition comprising ibudilast or a pharma- ceutical acceptable salt thereof, the pharmaceutical composition not comprising sulindac or a pharma- ceutical acceptable salt thereof, or bumetanide or a pharma- ceutical acceptable salt thereof, for use in the treatment of fragile X syndrome.

2. The pharmaceutical composition according to claim 1 , wherein the subject of treatment is a human.

3. 3. The pharmaceutical composition of claim 1 or 2, wherein the composition comprises 10 mg to 300 mg of ibudilast.

4. A pharmaceutical composition described in claim 1 or 2, wherein the composition contains 20 mg to 150 mg of ibudilast.

5. The pharmaceutical composition according to any one of claims 1 to 4, wherein administration is by one dose per day.

6. 6. The pharmaceutical composition of claim 5, wherein the single daily dose comprises 10 mg to 300 mg of ibudilast.

7. The pharmaceutical composition of claim 5, wherein the single daily dose contains 20 mg to 150 mg of ibudilast.

8. The pharmaceutical composition according to any one of claims 1 to 4, wherein administration is by two doses per day.

9. 9. The pharmaceutical composition of claim 8, wherein the dose comprises 20 mg to 100 mg of ibudilast.

10. The pharmaceutical composition of claim 8, wherein the dose comprises 20 mg to 50 mg of ibudilast.

11. The pharmaceutical composition according to any one of claims 1 to 10, which is administered orally.

12. The pharmaceutical composition according to any one of claims 1 to 10, which is administered parenterally, transdermally, sublingually, rectally or by inhalation administration.

13. The pharmaceutical composition according to any one of claims 1 to 12, wherein the patient shows signs of hyperactivity, social anxiety, memory loss and / or disruptive behaviour.

14. The pharmaceutical composition according to any one of claims 1 to 13, wherein the patient shows signs of hyperactivity, memory loss and / or disruptive behaviour.

15. 1. A pharmaceutical composition comprising ibudilast or a pharma- ceutical acceptable salt thereof for use in the treatment of fragile X syndrome, wherein ibudilast is the only active agent in said composition.

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