Methods for Treating Seizure Disorders and Prader-Willi Syndrome

Abstract

A method for treating a seizure disorder using (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharmaceutically acceptable salt of either of the foregoing is provided. The method also provides a therapeutic composition that can be used to ameliorate one or more symptoms of a seizure disorder. A method for treating Prader-Willi syndrome using (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharmaceutically acceptable salt of either of the foregoing is provided. The method also provides a therapeutic composition that can be used to ameliorate one or more symptoms of Prader-Willi syndrome.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Application No. 62 / 456,320, filed February 8, 2017, the entire disclosure of which is incorporated herein by reference. Technical Field Methods for treating seizure disorders and Prader-Willi syndrome are provided. [Background technology]

[0002] Seizure disorders usually involve abnormal neuronal activity in the brain, causing seizures that may manifest during abnormal behavior, sensations, convulsions, decreased awareness, and sometimes loss of consciousness. Seizures can be a symptom of many different diseases that may affect the brain. Epilepsy is a seizure disorder characterized by recurrent seizures. See, for example, Blume et al., Epilepsia. 2001;42:1212-1218. Epileptic seizures are usually characterized by abnormal electrical discharges in the brain and usually manifest as sudden, brief episodes of altered or decreased awareness, involuntary movements, or convulsions. Abnormal electrical activity in the brain can be measured or detected by electroencephalography (EEG). Clinical epileptic seizures may be preceded by abnormal electrical activity detected in EEG recordings as multifocal spikes that provide evidence of an epileptic seizure but do not accompany the seizure. See, for example, Jozwiak et al., European Journal of Paediatric Neurology, 2011, 15(5) 424-431 (Jozwiak et al.). Non-epileptic seizures may or may not involve abnormal electrical activity in the brain and may be caused by psychological problems or stress. Drug or alcohol withdrawal may also cause seizures. Seizure symptoms vary widely; some seizures are difficult to notice, while others are completely disabling. Seizure disorders include: epilepsy.

[0003] Hamartomas may be associated with certain seizure disorders. Hamartomas are mostly benign focal malformations that resemble neoplasms of the tissue of their origin. They are composed of tissue elements normally found in that location, but grow in a chaotic manner. Hamartomas may originate in the brain. Tuberous sclerosis complex (TSC) is an inherited seizure disorder characterized by hamartomatous growths in various organs. The earliest symptoms of TSC include cardiac tumors and cortical tubers, which can be seen even before birth. Patients with the disease may have a high incidence of epilepsy and cognitive problems due to multiple lesions in the brain. TSC lesions (cortical tubers) usually contain dysmorphic neurons, apparently eosinophilic giant cells, and white matter changes. Seizures associated with TSC are intractable. Gray-white hamartomas (also known as hypothalamic hamartomas) are benign tumors in which a disorganized collection of neurons and glia accumulate in the tuberous dura of the hypothalamus. Symptoms include laughter attacks, a disorder characterized by bouts of involuntary laughter accompanied by interval irritability, and depressed mood. Antiepileptic treatment before the onset of seizures can reduce the severity of epilepsy and the risk of mental retardation in infants with TSC. See, for example, Jozwiak et al.

[0004] Infantile spasms (IS) are a specific type of seizure disorder seen in infancy and childhood, also known as West syndrome, juvenile spasms, or epileptic spasms. West syndrome is characterized by infantile spasms, developmental regression, and a specific pattern on EEG testing called hypsarrhythmia (chaotic electroencephalogram). The onset of infantile spasms usually occurs within the first year of life, typically between 3 and 12 months, typically around 5 months. Seizures consist primarily of a sudden bending of the body forward with stiffening of the arms and legs; some children arch their back while straightening their arms and legs. The spasms tend to occur upon awakening or after feeding, often with up to 100 spasms at one time. Infants may develop dozens of clusters and hundreds of spasms per day. Infantile spasms usually end by mid-childhood, but may be replaced by other seizure types. The intellectual prognosis for children with infantile spasms is generally poor. Treatment with corticosteroids such as prednisone is standard, but serious side effects can occur. Some antiepileptic drugs, such as topiramate, may relieve some symptoms. Vigabatrin is approved by the U.S. Food and Drug Administration to treat infantile spasms in children aged 1 month to 2 years.

[0005] Lennox-Gastaut syndrome (LGS) is a severe seizure disorder. Seizures usually begin before age 4 years. Although it varies from patient to patient, seizure types may include tonic (rigidity of the body, upward deviation of the eyes, dilation of the pupils, and changes in breathing patterns), atonic (brief loss of muscle tone and consciousness that can cause a sudden fall), atypical absence (continuous staring), and myoclonus (sudden muscle jerks). Periods of frequent seizures may be mixed with short, relatively seizure-free periods. Many children with Lennox-Gastaut syndrome experience some degree of intellectual impairment or information processing problems, usually accompanied by developmental and behavioral problems. Lennox-Gastaut syndrome is caused by brain malformations, perinatal asphyxiation, severe head trauma, central nervous system infections, and inherited degenerative or metabolic conditions. In some cases, no cause can be found. Treatment for Lennox-Gastaut syndrome includes antiepileptic drugs such as clobazam; valproate, lamotrigine, felbamate, and topiramate. No single antiepileptic drug usually provides complete control of seizures. Children who initially improve may later develop a resistance to the medication or develop uncontrolled seizures.

[0006] CDKL5 disorder is an X-linked genetic seizure disorder that results in severe neurodevelopmental disabilities and early onset, and seizures are difficult to control. CDKL5 stands for cyclin-dependent kinase-like 5, a gene located on the X chromosome. The CDKL5 gene was previously called STK9. CDKL5 disorder is mostly associated with females, but has also been seen in males. The main feature associated with mutations in CDKL5 is the so-called epileptic encephalopathy, the onset of severe seizures within the first 6 months of life (often within the first 3 months), followed by poor neurocognitive development and the presence of typically repetitive hand movements (stereotypic). Most afflicted children are unable to walk, talk, or feed themselves, and many are confined to wheelchairs and dependent on others for everything. Many also suffer from scoliosis, visual impairment, sensory problems and various gastrointestinal disorders. Other symptoms of CDKL5 disorder often include low or poor muscle tone, hand-wringing behavior or hand-mousing, significant developmental delay, limited or absent speech, absent or poor eye contact, gastroesophageal reflux, constipation, small and cold feet, breathing irregularities such as hyperventilation, teeth grinding, episodes of laughing or crying for no reason, very limited manual skills, autistic-like tendencies, features such as cortical visual impairment (CVI), also known as "cortical blindness," apraxia, challenges with eating and drinking, sleep disorders, sideways glances, and a habit of crossing the legs. Currently, there are no approved drugs to treat CDKL5 disorder. Seizure management is challenging and often the most difficult health problem to manage. No single uniformly effective antiepileptic drug has been found, and multiple anticonvulsants are often required. Summary of the Invention [Problem to be solved by the invention]

[0007] Medications are used to treat seizure disorders and may be referred to as antiepileptic drugs (AEDs). Treatment of recurrent seizures has primarily focused on the use of at least one AED, with the adjunctive use of a second or even third drug if monotherapy fails. See Tolman and Faulkner, Ther Clin Risk Manag. 2011;7:367-375. However, approximately 30%-40% of epilepsy patients obtain inadequate seizure control with a single AED and require the use of adjunctive agents. Same as above A subset of this group develops regular and persistent seizure activity despite moderate doses of multiple AEDs. Same as above Thus, there remains a need for improved and / or additional therapies for treating seizure disorders.

[0008] Prader-Willi syndrome (PWS) is a genetic disease caused by the absence of expression of genes from the paternally inherited imprinted region of chromosome 15q11-q13, near the centromere (Aycan and Bas, J Clin Res Pediatr Endocrinol, 6(2):62-67(2014)). The frequency of the disease is between approximately 1 / 10,000 and 1 / 30,000 with approximately 400,000 PWS patients worldwide. PWS is a spectrum disorder that affects many systems in the body. Patients with PWS usually suffer from many symptoms including neurological, cognitive, endocrine, and behavioral abnormalities. Initially, infants may present with hypotonia (floppy baby syndrome) and difficulty sucking and feeding, which may result in delayed growth. Poor muscle tone, growth hormone deficiency, decreased levels of sex hormones, constant hunger and excessive appetite (hyperphagia) frequently occur in patients with PWS. They eat too much, resulting in weight gain, obesity, and a high incidence of diabetes. Other signs include short stature, poor motor skills, delayed genital development, and mild intellectual and learning disabilities. Patients with PWS may experience delayed speech and language development, and infertility. Behavioral symptoms include cognitive impairment, cognitive rigidity, emotional lability and obsessive-compulsive behavior, autistic symptoms, psychotic episodes, and bipolar disorder with psychosis. Other clinical symptoms include excessive daytime sleepiness, scoliosis, osteopenia / osteoporosis, decreased gastrointestinal motility, sleep disorders, and decreased pain sensitivity.

[0009] PWS is the most common genetic neurodevelopmental disorder associated with obesity. Data show that PWS is associated with an approximately 50% reduction in plasma BDNF levels normalized to body weight (Han et al., J. Clin. Endo. Metab., 95, 3532-36 (2010)). Studies also reveal that selective upregulation of BDNF in the hypothalamus suppresses appetite and weight gain in mice fed a high-fat diet, and very high levels of expression using viral vector gene transfer cause severe weight loss in normal control chow-fed mice (Cao, et al., Nat Med., 15(4):447-54 (2009)). BDNF appears to act downstream of other feeding regulators, notably leptin and the MC4 receptor.

[0010] Currently, there is no cure for PWS. Growth hormone, exercise, and dietary management can help increase muscle mass and control weight. Treatment with human growth hormone beginning by age 2 years has been reported to improve body composition, motor function, height, and lipid profile. See Carrel et al., J Clin Endocrinol Metab., 95(3):1131-1136 (2010 Mar). Other treatments include oxytocin, sex hormones, and behavioral therapy. However, most patients with PWS require specialized care and management throughout their lives. Improved and / or additional therapies to treat PWS remain needed. [Means for solving the problem]

[0011] overview A method for treating a seizure disorder is provided, in an embodiment, the method comprises administering an effective amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, the method for treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in one or more symptoms of the disorder. In an embodiment, the method for treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in the subject's next day function. In an embodiment, the method of treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof prior to the onset of a clinical seizure following detection of an abnormal EEG to reduce or prevent symptoms of the seizure disorder. In an embodiment, the method of treating an abnormal EGG signature comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject having an abnormal EGG signature.

[0012] In an embodiment, the method of treating a seizure disorder comprises administering an effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in one or more symptoms of the disorder. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in the subject's next day functioning. In an embodiment, the method of treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof after detection of an abnormal EEG and prior to the onset of a clinical seizure to reduce or prevent symptoms of the seizure disorder. In an embodiment, the method of treating an abnormal EGG signature comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject having an abnormal EGG signature.

[0013] In an embodiment, the method of treating a seizure disorder comprises administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof.

[0014] In embodiments, the seizure disorder includes epilepsy, epilepsy with generalized tonic-clonic seizures, epilepsy with myoclonic absence, frontal lobe epilepsy, temporal lobe epilepsy, Landau-Kleffner syndrome, Dravet syndrome, Rasmussen syndrome, Dawes syndrome, CDKL5 disorder, infantile spasms (West syndrome), Lennox-Gastaut syndrome (LGS), Retz syndrome, Otahara syndrome, CDKL5 disorder, childhood absence epilepsy, essential tremor, and acute repetitive seizures, benign rolandic epilepsy, status epilepticus, refractory status epilepticus, very refractory status epilepticus (SRSE), PCDH19 childhood epilepsy, drug withdrawal induced seizures, seizures due to alcohol withdrawal, and increased seizure activity or spontaneous seizures (increased seizure activity; also called consecutive or cluster seizures). In embodiments, the seizure disorder is status epilepticus.

[0015] Methods of treating Prader-Willi syndrome are provided, in embodiments comprising administering an effective amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In embodiments, the methods of treating Prader-Willi syndrome comprise administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in one or more symptoms of the syndrome. In embodiments, the methods of treating Prader-Willi syndrome comprise administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in the subject's next day functioning. In an embodiment, a method for treating Prader-Willi syndrome comprises administering an effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, a method for treating Prader-Willi syndrome comprises administering an effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in one or more symptoms of the syndrome. In an embodiment, a method for treating Prader-Willi syndrome comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide improvement in the subject's next day functioning. In an embodiment, a method for treating Prader-Willi syndrome comprises administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Detailed Description A method for treating a seizure disorder is provided, which in an embodiment comprises administering an effective amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, the method for treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in one or more symptoms of the disorder. In an embodiment, the method for treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in the subject's next day function. In an embodiment, the method of treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof after detection of an abnormal EEG and prior to the onset of a clinical seizure to reduce or prevent symptoms of the seizure disorder. In an embodiment, the method of treating an abnormal EGG signature comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject having an abnormal EGG signature.

[0017] In an embodiment, the method of treating a seizure disorder comprises administering an effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in one or more symptoms of the disorder. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in the subject's next day functioning. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof prior to the onset of a clinical seizure following detection of an abnormal EEG to reduce or prevent symptoms of the seizure disorder. In an embodiment, the method of treating an abnormal EGG sign comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject having an abnormal EGG sign.

[0018] In an embodiment, the method of treating a seizure disorder comprises administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof.

[0019] Examples of seizure disorders include epilepsy, epilepsy with generalized tonic-clonic seizures, epilepsy with myoclonic absence, frontal lobe epilepsy, temporal lobe epilepsy, Landau-Kleffner syndrome, Rasmussen syndrome, Dravet syndrome, Dawes syndrome, CDKL5 disorder, infantile spasms (West syndrome), juvenile myoclonic epilepsy (JME), vaccine-associated encephalopathy, refractory childhood epilepsy (ICE), Lennox-Gastaut syndrome (LGS), Retz syndrome, Otahara syndrome, CDKL5 disorder, childhood absence epilepsy, essential tremor, acute repetitive seizures, benign rolandic epilepsy, status epilepticus, refractory status epilepticus, very refractory status epilepticus (SRSE), PCDH19 childhood epilepsy, drug withdrawal induced seizures, seizures due to alcohol withdrawal, increased seizure activity or spontaneous seizures (also called consecutive or cluster seizures). In an embodiment, the seizure disorder is associated with a sodium channel protein type 1 subunit alpha (Scn1a) associated disorder.

[0020] In an embodiment, the seizure disorder is status epilepticus (SE). SE is characterized by more than 5 minutes or more than one seizure within 5 minutes without the person returning to normal between seizures. SE can be a dangerous condition that can lead to death if treatment is delayed. SE can be convulsive, with a regular pattern of contraction and extension of the arms and legs, or non-convulsive, with relatively long periods of altered level of consciousness but without extensive limb flexion or extension due to seizure activity. Convulsive SE (CSE) can be further classified as (a) tonic-clonic SE, (b) tonic SE, (c) clonic SE, and (d) myoclonic SE. Non-convulsive SE (NCSE) is characterized by abnormal mental status, unresponsiveness, eye movement abnormalities, sustained electromyographic seizures, and possible response to anticonvulsant medications.

[0021] In an embodiment, the method of treating a seizure disorder comprises administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the subject shows improvement in one or more symptoms of the disorder. In an embodiment, the method of treating a seizure disorder comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the subject shows improvement in one or more symptoms of the disorder.

[0022] Symptoms of seizure disorders include, but are not limited to, episodes with ataxia, gait disturbance, speech disturbance, speech, cognitive impairment, dyskinesia, clinical seizures, subclinical seizures, hypotonia, hypertonia, salivation and mouthing behavior, aura, convulsions, repetitive movements, and abnormal sensations. In embodiments, the provided methods and compositions may reduce or prevent one or more different types of seizures. In general, seizures may include convulsions, repetitive movements, abnormal sensations, and combinations thereof. Seizures may be classified as focal seizures (also called partial seizures) and generalized seizures. Focal seizures affect only one side of the brain, while generalized seizures affect both sides of the brain. Particular types of focal seizures include simple focal seizures, complex focal seizures, and secondarily generalized seizures. Simple focal seizures may be restricted or concentrated to a particular lobe (e.g., the temporal, frontal, parietal, or occipital lobe). Complex focal seizures generally affect a larger portion of one hemisphere than simple focal seizures, but generally originate in the temporal or frontal lobes. When focal seizures spread from one side (hemisphere) of the brain to both sides, the seizures are called secondary generalized seizures. Specific types of generalized seizures include absence (also called petit mal), tonic, atonic, myoclonic, tonic-clonic (also called grand mal), and clonic. Symptoms of seizure disorders include seizures, cognitive impairment, autism, laughter, a disorder characterized by bouts of involuntary laughter with interval irritability, and depressed mood. Symptoms of seizure disorders include those associated with infantile spasms, such as seizures, cognitive impairment, developmental regression, and hypsarrhythmia. Symptoms of seizure disorders include those associated with Lennox-Gastaut syndrome, such as seizures, developmental delay, cognitive impairment, and behavioral disorders.Symptoms of seizure disorder include seizures, scoliosis, visual impairment, sensory problems and gastrointestinal problems, low or poor muscle tone, hand wringing or hand mouthing, significant developmental delay, limited or absent speech, absent or poor eye contact, gastroesophageal reflux, constipation, small and cold feet, breathing irregularities such as hyperventilation, teeth grinding, episodes of laughing or crying for no reason, very limited manual skills, autistic-like tendencies, cortical visual impairment (CVI), also known as "cortical blindness", apraxia, challenges with eating and drinking, sleep disorders, sideways glances, and features associated with CDKL5 such as the habit of crossing one's legs.

[0023] In embodiments, the term "effective amount" or "therapeutically effective amount" as applied to a seizure disorder means an amount of a compound, material, composition, medicament, or other material effective to achieve a particular pharmacological and / or physiological effect associated with a seizure disorder, such as, but not limited to, one or more of the following: reduction or elimination of episodes with ataxia, reduction or elimination of gait disturbances, reduction or elimination of speech disturbances, reduction or elimination of vocalizations, reduction or elimination of cognitive impairment, reduction or elimination of dyskinesias, reduction or elimination of clinical seizures, reduction or elimination of subclinical seizures, reduction or elimination of hypotonia, reduction or elimination of hypertonia, salivation, and reduction or elimination of mouse behavior, reduction or elimination of aura, reduction or elimination of convulsions, reduction or elimination of repetitive movements, reduction or elimination of abnormal sensations, reduction or elimination of one or more different types of seizures, reduction or elimination of convulsions, reduction or elimination of repetitive movements, reduction or elimination of abnormal sensations, reduction or elimination of simple focal seizures, reduction or elimination of complex focal seizures, reduction or elimination of generalized seizures, reduction or elimination of absence (also called petit mal), reduction or elimination of tonic seizures, reduction or elimination of atonic seizures, reduction or elimination of myoclonic seizures, reduction or elimination of tonic-clonic seizures (also called grand mal), reduction or elimination of clonic seizures. For example, reduction or elimination of TSC symptoms such as seizures, cognitive impairment, autism, laughter attacks, a disorder characterized by bouts of involuntary laughter accompanied by interval irritability, and depressed mood. For example, reducing or eliminating symptoms associated with infantile spasms, such as seizures, cognitive impairment, developmental regression, and hypsarrhythmia. For example, reducing or eliminating symptoms associated with Lennox-Gastaut syndrome, such as seizures, developmental delay, cognitive impairment, and behavioral disorders.By way of example, the reduction or elimination of symptoms associated with CDKL5, such as seizures, scoliosis, visual impairment, sensory problems and gastrointestinal disorders, low or poor muscle tone, hand wringing or hand mouthing, significant developmental delay, limited or absent speech, absent or absent eye contact, gastroesophageal reflux, constipation, small and cold feet, breathing irregularities such as hyperventilation, teeth grinding, episodes of laughing or crying for no reason, very limited manual skills, autistic tendencies, characteristics such as cortical visual impairment (CVI), also known as "cortical blindness", apraxia, eating and drinking challenges, sleep disorders, sideways glances, and cross-legged habit. In an embodiment, an effective amount results in enhanced cognitive function, increased daytime activity, improved learning (either speed or ease of learning), improved attention, improved social behavior, and / or improved cerebrovascular function. In an embodiment, an effective amount means an amount that may be adequate to prevent a decline in any one or more of the above qualities, or, in an embodiment, to improve any one or more of the above qualities. In embodiments, the effective amount may be suitable for reducing the extent or rate of decline in cognitive ability or function of a subject, and / or the effective amount may be suitable for delaying the onset of such decline.Such effectiveness may be achieved, for example, by administering the compositions described herein to an individual or population.In embodiments, such reduction, delay in decline, or amelioration in an individual or population may be relative to a control subject or cohort population that has not been treated or administered the composition or agent.

[0024] The dosage may vary depending on a variety of factors, such as subject-dependent variables (eg, age, immune system, health status, etc.), the disease or disorder being treated, as well as the route of administration and the pharmacokinetics of the agent being administered.

[0025] Many medicines are administered as fixed doses at regular intervals to achieve a therapeutic effect. The duration of action is usually reflected in the plasma half-life of the drug. Because efficacy often depends on sufficient exposure within the central nervous system, administration of CNS drugs with short half-lives may require frequent maintenance dosing. The plasma elimination half-life of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid is approximately 4-6 hours. Cmax increases dose-proportionally over the 5 mg to 500 mg range; whereas, AUC increases more than proportionally over that dose range. (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid is 9-10 times more potent as an inactivator of GABA-AT than (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid and may display similar pharmacokinetics.

[0026] The structure of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid can be represented as follows: [ka]

[0027] The structure of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid can be represented as follows: [ka]

[0028] In an embodiment, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid may be provided as an acid addition salt, a zwitterion hydrate, a zwitterion anhydrate, a hydrochloride or hydrobromide salt, or in the form of a zwitterion monohydrate. Acid addition salts include, but are not limited to, maleic acid, fumaric acid, benzoic acid, ascorbic acid, succinic acid, oxalic acid, bismethylenesalicylic acid, methanesulfonic acid, ethanedisulfonic acid, acetic acid, propionic acid, tartaric acid, salicylic acid, citric acid, gluconic acid, lactic acid, malic acid, mandelic acid, cinnamic acid, citraconic acid, aspartic acid, stearic acid, palmitic acid, itaconic acid, glycolic acid, pantothenic acid, p-aminobenzoic acid, glutamic acid, benzenesulfonic acid, or theophylline acetate addition salts, as well as 8-halotheophylline, such as 8-bromo-theophylline. In embodiments, inorganic acid addition salts can be used, such as, but not limited to, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid, phosphoric acid, or nitric acid addition salts.

[0029] In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid may be provided as an acid addition salt, a zwitterion hydrate, a zwitterion anhydrate, a hydrochloride or hydrobromide salt, or in the form of a zwitterion monohydrate. Acid addition salts include, but are not limited to, maleic acid, fumaric acid, benzoic acid, ascorbic acid, succinic acid, oxalic acid, bismethylenesalicylic acid, methanesulfonic acid, ethanedisulfonic acid, acetic acid, propionic acid, tartaric acid, salicylic acid, citric acid, gluconic acid, lactic acid, malic acid, mandelic acid, cinnamic acid, citraconic acid, aspartic acid, stearic acid, palmitic acid, itaconic acid, glycolic acid, pantothenic acid, p-aminobenzoic acid, glutamic acid, benzenesulfonic acid, or theophylline acetate addition salts, as well as 8-halotheophylline, such as 8-bromo-theophylline. In embodiments, inorganic acid addition salts can be used, such as, but not limited to, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, sulfamic acid, phosphoric acid, or nitric acid addition salts.

[0030] In an embodiment, the method includes treating a seizure disorder by administering about 0.1 mg to about 1500 mg of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as its hydrochloride, to a subject in need thereof. In an embodiment, the method includes treating a seizure disorder by administering about 0.5 mg to about 1000 mg of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as its hydrochloride, to a subject in need thereof. In an embodiment, the amount of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as its hydrochloride, for treating a seizure disorder can be between 0.1 and 1500 mg / day, or 0.01 mg / kg / day to 15 mg / kg / day. For example, the daily dosage may be, for example, about 0.1-1500 mg, 0.1-1250 mg, 0.1-1000 mg, 0.1-750 mg, 0.1-500 mg, 0.1-450 mg, 0.1-300 mg, 0.1-250 mg, 0.1-200 mg, 0.1-175 mg, 0.1-150 mg, 0.1-125 mg, 0.1-100 mg, 0.1-75 mg, 0.1-50 mg, 0.1-30 mg, 0.1-25 mg, 0.1-20 mg, 0.1-15 mg, 0.1-10 mg, 0.1-5 mg, 0.1-1 mg, 1-1500 mg, 1-1000 mg, 1-500 mg, 1-300 mg, 1-250 mg, 1-200 mg, mg, 1~175 mg, 1~150 mg, 1~125 mg, 1~100 mg, 1~75 mg, 1~50 mg, 1~30 mg, 1~25 mg, 1~20 mg, 1~15 mg, 1~10 mg, 1~5 mg, 5~1500 mg, 5~1000 mg, 5~500 mg, 5~300 mg, 5~250 mg, 5~200 mg, 5~175 mg, 5~150 mg, 5~125 mg, 5~100 mg, 5~75 mg, 5~50 mg, 5~30 mg, 5~25 mg, 5~20 mg, 5~15 mg, 5~10 mg, 10~1500 mg, 10~1000 mg, 10~500 mg, 10~300mg、10~250 mg、10~200 mg、10~175 mg、10~150 mg、10~125 mg、10~100 mg、10~75 mg、10~50 mg、10~30 mg、10~25 mg、10~20 mg、10~15 mg、15~1500 mg、15~1000 mg、15~500 mg、15~300 mg、15~250 mg、15~200 mg、15~175 mg、15~150 mg、15~125 mg、15~100 mg、15~75 mg、15~50 mg、15~30 mg、15~25 mg、15~20 mg、20~1500 mg、20~1000 mg、20~500 mg、20~300 mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~1500 mg、25~1000 mg、25~500 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~75 mg、25~50 mg、25~30 mg、30~1500 mg、30~1000 mg、30~500 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、35~1500 mg、35~1000 mg、35~500 mg、35~300 mg、35~250 mg、35~200 mg、35~175 mg、35~150 mg、35~125 mg、35~100 mg、35~75 mg、35~50 mg、40~1500 mg、40~1000 mg、40~500 mg、40~300 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~1500 mg、50~1000 mg、50~500 mg、50~300 mg、50~250 mg、50~200 mg、50~175 mg、50~150 mg、50~125 mg、50~100 mg、50~75mg, 75~1500 mg, 75~1000 mg, 75~500 mg, 75~300 mg, 75~250 mg, 75~200 mg, 75~175 mg, 75~150 mg, 75~125 mg, 75~100 mg, 100~1500 mg, 100~1000 mg, 100~500 mg, 100~300 mg, 100~250 mg, 100~200 mg, 100~175 mg, 100~150 mg, 100~125 mg, 125~1500 mg, 125~1000 mg, 125~500 mg, 125~300 mg, 125~250 mg, 125~200 mg, 125~175 mg, 125~150 mg, 150-1500 mg, 150-1000 mg, 150-500 mg, 150-300 mg, 150-250 mg, 150-200 mg, 150-175 mg, 175-1500 mg, 175-1000 mg, 175-500 mg, 175-300 mg, 175-250 mg, 175-200 mg, 200-1500 mg, 200-1000 mg, 200-500 mg, 200-300 mg, 200-250 mg, 250-1500 mg, 250-1000 mg, 250-500 mg, 250-300 mg, 7.5-15 mg, 2.5-5 mg, 1-5 mg, as well as by way of example, about 0.25 mg, 0.5 The dosages may be 0.75 mg, 1 mg, 1.25 mg, 1.5 mg, 1.75 mg, 2.0 mg, 2.5 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 27.5 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 75 mg, 100 mg, 125 mg, 150 mg, 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 400 mg, and 500 mg.

[0031] In an embodiment, a pharmaceutical composition for treating a seizure disorder may be administered in an amount of, for example, about 0.01-500 mg, 0.1-500 mg, 0.1-450 mg, 0.1-300 mg, 0.1-250 mg, 0.1-200 mg, 0.1-175 mg, 0.1-150 mg, 0.1-125 mg, 0.1-100 mg, 0.1-75 mg, 0.1-50 mg, 0.1-30 mg, 0.1-25 mg, 0.1-20 mg, 0.1-15 mg, 0.1-10 mg, 0.1-5 mg, 0.1-1 mg, 0.5-500 mg, 0.5-450 mg, 0.5-300 mg, 0.5-250 mg, 0.5-200 mg, 0.5-175 mg, 0.5-150 mg, mg, 0.5~125 mg, 0.5~100 mg, 0.5~75 mg, 0.5~50 mg, 0.5~30 mg, 0.5~25 mg, 0.5~20 mg, 0.5~15 mg, 0.5~10 mg, 0.5~5 mg, 0.5~1 mg, 1~500 mg, 1~450 mg, 1~300 mg, 1~250 mg, 1~200 mg, 1~175 mg, 1~150 mg, 1~125 mg, 1~100 mg, 1~75 mg, 1~50 mg, 1~30 mg, 1~25 mg, 1~20 mg, 1~15 mg, 1~10 mg, 1~5 mg, 5~500 mg, 5~450 mg, 5~300 mg, 5~250 mg, 5~200 mg, 5~175 mg, 5~150 mg, 5~125 mg, 5~100 mg, 5~75 mg, 5~50 mg, 5~30 mg, 5~25 mg, 5~20 mg, 5~15 mg, 5~10 mg, 10~500 mg, 10~450 mg, 10~300 mg, 10~250 mg, 10~200 mg, 10~175 mg, 10~150 mg, 10~125 mg, 10~100 mg, 10~75 mg, 10~50 mg, 10~30 mg, 10~25 mg, 10~20 mg, 10~15 mg, 15~500 mg, 15~450 mg, 15~300 mg, 15~250 mg, 15~200 mg, 15~175 mg, 15~150 mg, 15~125 mg, 15~100 mg, 15~75 mg, 15~50 mg, 15~30 mg, 15~25 mg, 15~20 mg, 20~500 mg, 20~450mg、20~300 mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~500 mg、25~450 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~80 mg、25~75 mg、25~50 mg、25~30 mg、30~500 mg、30~450 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、40~500 mg、40~450 mg、40~400 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~500 mg、50~450 mg、50~300 mg、50~250 mg、50~200 mg、50~175 mg、50~150 mg、50~125 mg、50~100 mg、50~75 mg、75~ 500 mg、75~450 mg、75~300 mg、75~250 mg、75~200 mg、75~175 mg、75~150 mg、75~125 mg、75~100 mg、100~500 mg、100~450 mg、100~300 mg、100~250 mg、100~200 mg、100~175 mg、100~150 mg、100~125 mg、125~500 mg、125~450 mg、125~300 mg、125~250 mg、125~200 mg、125~175 mg、125~150 mg、150~500 mg、150~450 mg、150~300 mg、150~250 mg、150~200 mg、200~500 mg、200~450 mg、200~300 mg、200~250 mg、250~500 mg、250~450 mg、250~300 mg、300~500 mg、300~450 mg、300~400 mg、300~350 mg、350~500 mg、350~450mg, 350-400 mg, 400-500 mg, 400-450 mg, and by way of example only, 0.1 mg, 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 125 mg, 150 mg 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, and 500 mg. The composition may comprise (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof in an amount of about 1 mg.

[0032] Typically, dosages may be administered to a subject with a seizure disorder 1, 2, 3 or 4 times a day, every other day, once a week, or once a month. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharmacologic acceptable salt thereof is administered to a subject with a seizure disorder at a dose of 1-50 mg / administration twice a day (e.g., morning and evening) or three times a day (e.g., breakfast, lunch, and dinner). In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof is administered to a subject with a seizure disorder in one or more doses of 100 mg / day, 95 mg / day, 90 mg / day, 85 mg / day, 80 mg / day, 75 mg / day, 70 mg / day, 65 mg / day, 60 mg / day, 55 mg / day, 50 mg / day, 45 mg / day, 40 mg / day, 35 mg / day, 30 mg / day, 25 mg / day, 20 mg / day, 15 mg / day, 10 mg / day, 5 mg / day, 4 mg / day, 3 mg / day, 3 mg / day, 2 mg / day, 1 mg / day. In an embodiment, the dosage for an adult is about 5-80 mg / day, and can be increased up to 150 mg / day. Dosages can be lower for infants and children than for adults. In embodiments, the dose for an infant or child is about 0.1 to 50 mg per day, which can be administered in one or two, three or four divided doses. In embodiments, the pediatric dose is 0.75 mg / kg / day to 1.5 mg / kg / day. In embodiments, subjects may be started on a lower dose and the dosage increased over time.

[0033] In an embodiment, a method for treating a seizure disorder is provided, comprising administering a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for one hour or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for two hours or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for three hours or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for 4 hours or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for 6 hours or more after administration to the subject. In an embodiment, a method of treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for 8, 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration to the subject.In an embodiment, according to the present disclosure, after administration of the pharmaceutical composition to a subject, at least one symptom is improved for 12 hours.In an embodiment, the pharmaceutical composition provides an improvement in the subject's next day function.For example, the pharmaceutical composition can provide an improvement in one or more symptoms of disease for about 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours or more after administration and after awakening from sleep.

[0034] In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof is administered to a subject with a seizure disorder in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof may be administered to a subject with a seizure disorder in separate dosage forms or combined in one dosage form. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof may be administered simultaneously or at intervals to a subject with a seizure disorder.

[0035] In an embodiment, the method includes treating a seizure disorder by administering about 0.005 mg to about 750 mg of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, e.g., hydrochloride, to a subject in need thereof. In an embodiment, the amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, e.g., hydrochloride, for treating a seizure disorder can be between 0.005 and 1000 mg / day, or 0.005 mg / kg / day to 14 mg / kg / day. For example, the daily dosage may be, for example, about 0.01-750 mg, 0.01-700 mg, 0.01-500 mg, 0.01-250 mg, 0.01-200 mg, 0.01-175 mg, 0.01-150 mg, 0.01-125 mg, 0.01-100 mg, 0.01-75 mg, 0.01-50 mg, 0.01-30 mg, 0.01-25 mg, 0.01-20 mg, 0.01-15 mg, 0.01-10 mg, 0.01-5 mg, 0.01-4 mg, 0.01-3 mg, 0.01-2 mg, 0.01-1 mg, 0.01-0.75 mg, 0.01-0.5 mg, 0.01-0.25 mg, 0.01-0.1 mg, 0.1~750 mg, 0.1~700 mg, 0.1~500 mg, 0.1~250 mg, 0.1~200 mg, 0.1~175 mg, 0.1~150 mg, 0.1~125 mg, 0.1~100 mg, 0.1~75 mg, 0.1~50 mg, 0.1~30 mg, 0.1~25 mg, 0.1~20 mg, 0.1~15 mg, 0.1~10 mg, 0.1~5 mg, 0.1~4 mg, 0.1~3 mg, 0.1~2 mg, 0.1~1 mg, 0.1~0.75 mg, 0.1~0.5 mg, 0.1~0.25 mg, 0.25~750 mg, 0.25~700 mg, 0.25~500 mg, 0.25~250 mg, 0.25~200 mg, 0.25~175 mg, 0.25~150 mg, 0.25~125 mg, 0.25~100 mg, 0.25~75 mg, 0.25~50 mg, 0.25~30 mg, 0.25~25 mg, 0.25~20 mg, 0.25~15 mg、0.25~10 mg、0.25~5 mg、0.25~4 mg、0.25~3 mg、0.25~2 mg、0.25~1 mg、0.25~0.75 mg、0.25~0.5 mg、0.3~750 mg、0.5~700 mg、0.3~500 mg、0.3~250 mg、0.3~200 mg、0.3~175 mg、0.3~150 mg、0.3~125 mg、0.3~100 mg、0.3~75 mg、0.3~50 mg、0.3~30 mg、0.3~25 mg、0.3~20 mg、0.3~15 mg、0.3~10 mg、0.3~5 mg、0.3~4 mg、0.3~3 mg、0.3~2 mg、0.3~1 mg、0.3~0.75 mg、0.3~0.5 mg,0.4~750 mg、0.4~700 mg、0.4~500 mg、0.4~250 mg、0.4~200 mg、0.4~175 mg、0.4~150 mg、0.4~125 mg、0.4~100 mg、0.4~75 mg、0.4~50 mg、0.4~30 mg、0.4~25 mg、0.4~20 mg、0.4~15 mg、0.4~10 mg、0.4~5 mg、0.4~4 mg、0.4~3 mg、0.4~2 mg、0.4~1 mg、0.4~0.75 mg、0.4~0.5 mg,0.5~750 mg、0.5~700 mg、0.5~500 mg、0.5~250 mg、0.5~200 mg、0.5~175 mg、0.5~150 mg、0.5~125 mg、0.5~100 mg、0.5~75 mg、0.5~50 mg、0.5~30 mg、0.5~25 mg、0.5~20 mg、0.5~15 mg、0.5~10 mg、0.5~5 mg、0.5~4 mg、0.5~3 mg、0.5~2 mg、0.5~1 mg、0.5~0.75 mg、0.75~750 mg、0.75~700 mg、0.75~500 mg、0.75~250 mg、0.75~200 mg、0.75~175 mg、0.75~150 mg、0.75~125 mg、0.75~100 mg、0.75~75 mg、0.75~50 mg、0.75~30 mg、0.75~25 mg、0.75~20 mg、0.75~15 mg、0.75~10 mg、0.75~5 mg、0.75 - 4 mg, 0.75 - 3 mg, 0.75 - 2 mg, 0.75 - 1 mg, 1 - 750 mg, 1 - 700 mg, 1 - 500 mg, 1 - 250 mg, 1 - 200 mg, 1 - 175 mg, 1 - 150 mg, 1 - 125 mg, 1 - 100 mg, 1 - 75 mg, 1 - 50 mg, 1 - 30 mg, 1 - 25 mg, 1 - 20 mg, 1 - 15 mg, 1 - 10 mg, 1 - 5 mg, 1 - 4 mg, 1 - 3 mg, 1 - 2 mg, 2 - 750 mg, 2 - 700 mg, 2 - 500 mg, 2 - 250 mg, 2 - 200 mg, 2 - 175 mg, 2 - 150 mg, 2 - 125 mg, 2 - 100 mg, 2 - 75 mg, 2 - 50 mg, 2 - 30 mg, 2 - 25 mg, 2 - 20 mg, 2 - 15 mg, 2 - 10 mg, 2 - 5 mg, 2 - 4 mg, 2 - 3 mg, 3 - 750 mg, 3 - 700 mg, 3 - 500 mg, 3 - 250 mg, 3 - 200 mg, 3 - 175 mg, 3 - 150 mg, 3 - 125 mg, 3 - 100 mg, 3 - 75 mg, 3 - 50 mg, 3 - 30 mg, 3 - 25 mg, 3 - 20 mg, 3 - 15 mg, 3 - 10 mg, 3 - 5 mg, 3 - 4 mg, 4 - 750 mg, 4 - 700 mg, 4 - 500 mg, 4 - 250 mg, 4 - 200 mg, 4 - 175 mg, 4 - 150 mg, 4 - 125 mg, 4 - 100 mg, 4 - 75 mg, 4 - 50 mg, 4 - 30 mg, 4 - 25 mg, 4 - 20 mg, 4 - 15 mg, 4 - 10 mg, 4 - 5 mg, 5 - 750 mg, 5 - 700 mg, 5 - 500 mg, 5 - 250 mg, 5 - 200 mg, 5 - 175 mg, 5 - 150 mg, 5 - 125 mg, 5 - 100 mg, 5 - 75 mg, 5 - 50 mg, 5 - 30 mg, 5 - 25 mg, 5 - 20 mg, 5 - 15 mg, 5 - 10 mg, 7.5 - 15 mg, 2.5 - 5 mg range, and by way of example, for example, about 0.01 mg, 0.025 mg, 0.05 mg, 0.075 mg, 0.1 mg, 0.2 mg, 0.25 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.75 mg, 1 mg, 1.25 mg, 1.5 mg, 1.75 mg, 2.0 mg, 2.5 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.Doses of 5 mg, 5 mg, 6 mg, 7 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 27.5 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 75 mg, 100 mg, 125 mg, 150 mg, 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 400 mg and 500 mg.

[0036] In an embodiment, a pharmaceutical composition for treating a seizure disorder may be administered in an amount of, for example, about 0.001-500 mg, 0.01-500 mg, 0.01-450 mg, 0.01-300 mg, 0.01-250 mg, 0.01-200 mg, 0.01-175 mg, 0.01-150 mg, 0.01-125 mg, 0.01-100 mg, 0.01-75 mg, 0.01-50 mg, 0.01-30 mg, 0.01-25 mg, 0.01-20 mg, 0.01-15 mg, 0.01-10 mg, 0.01-5 mg, 0.01-1 mg, 0.025-500 mg, 0.025-450 mg, 0.025-300 mg, 0.025-250 mg, mg, 0.025~200 mg, 0.025~175 mg, 0.025~150 mg, 0.025~125 mg, 0.025~100 mg, 0.025~75 mg, 0.025~50 mg, 0.025~30 mg, 0.025~25 mg, 0.025~20 mg, 0.025~15 mg, 0.025~10 mg, 0.025~5 mg, 0.025~1 mg, 0.05~500 mg, 0.05~450 mg, 0.05~300 mg, 0.05~250 mg, 0.05~200 mg, 0.05~175 mg, 0.05~150 mg, 0.05~125 mg, 0.05~100 mg, 0.05~75 mg, 0.05~50 mg, 0.05~30 mg, 0.05~25 mg, 0.05~20 mg, 0.05~15 mg, 0.05~10 mg, 0.05~5 mg, 0.05~1 mg, 0.075~500 mg, 0.075~450 mg, 0.075~300 mg, 0.075~250 mg, 0.075~200 mg, 0.075~175 mg, 0.075~150 mg, 0.075~125 mg, 0.075~100 mg, 0.075~75 mg, 0.075~50 mg, 0.075~30 mg, 0.075~25 mg, 0.075~20 mg, 0.075~15 mg, 0.075~10 mg, 0.075~5 mg, 0.075~1mg, 0.1~500 mg, 0.1~450 mg, 0.1~300 mg, 0.1~250 mg, 0.1~200 mg, 0.1~175 mg, 0.1~150 mg, 0.1~125 mg, 0.1~100 mg, 0.1~75mg、0.1~50 mg、0.1~30 mg、0.1~25 mg、0.1~20 mg、0.1~15 mg、0.1~10 mg、0.1~5 mg、0.1~1mg、0.25~500 mg、0.25~450 mg、0.25~300 mg、0.25~250 mg、0.25~200 mg、0.25~175 mg、0.25~150 mg、0.25~125 mg、0.25~100 mg、0.25~75 mg、0.25~50 mg、0.25~30 mg、0.25~25 mg、0.25~20 mg、0.25~15 mg、0.25~10 mg、0.25~5 mg、0.25~1mg、0.05~500 mg、0.5~450 mg、0.5~300 mg、0.5~250 mg、0.5~200 mg、0.5~175 mg、0.5~150 mg、0.5~125 mg、0.5~100 mg、0.5~75 mg、0.5~50 mg、0.5~30 mg、0.5~25 mg、0.5~20 mg、0.5~15 mg、0.5~10 mg、0.5~5 mg、0.5~1mg、1~500 mg、1~450 mg、1~300 mg、1~250 mg、1~200 mg、1~175 mg、1~150 mg、1~125 mg、1~100 mg、1~75 mg、1~50 mg、1~30 mg、1~25 mg、1~20 mg、1~15 mg、1~10 mg、1~5 mg、1~4 mg、1~3 mg、1~2 mg、2~500 mg、2~450 mg、2~300 mg、2~250 mg、2~200 mg、2~175 mg、2~150 mg、2~125 mg、2~100 mg、2~75 mg、2~50 mg、2~30 mg、2~25 mg、2~20 mg、2~15 mg、2~10 mg、2~5 mg、3~500 mg、3~450 mg、3~300 mg、3~250 mg、3~200 mg、3~175 mg、3~150 mg、3~125 mg、3~100 mg、3~75 mg、3~50 mg、3~30 mg、3~25 mg、3~20 mg、3~15 mg、3~10 mg、3~5 mg、4~500 mg、4~450 mg、4~300 mg、4~250 mg、4~200 mg、4~175 mg、4~150 mg、4~125mg、4~100 mg、4~75 mg、4~50 mg、4~30 mg、4~25 mg、4~20 mg、4~15 mg、4~10 mg、4~5 mg、5~500 mg、5~450 mg、5~300 mg、5~250 mg、5~200 mg、5~175 mg、5~150 mg、5~125 mg、5~100 mg、5~75 mg、5~50 mg、5~30 mg、5~25 mg、5~20 mg、5~15 mg、5~10 mg、10~500 mg、10~450 mg、10~300 mg、10~250 mg、10~200 mg、10~175 mg、10~150 mg、10~125 mg、10~100 mg、10~75 mg、10~50 mg、10~30 mg、10~25 mg、10~20 mg、10~15 mg、15~500 mg、15~450 mg、15~300 mg、15~250 mg、15~200 mg、15~175 mg、15~150 mg、15~125 mg、15~100 mg、15~75 mg、15~50 mg、15~30 mg、15~25 mg、15~20 mg、20~500 mg、20~450 mg、20~300 mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~500 mg、25~450 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~80 mg、25~75 mg、25~50 mg、25~30 mg、30~500 mg、30~450 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、40~500 mg、40~450 mg、40~400 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~500 mg、50~450 mg、50~300 mg、50~250mg, 50~200 mg, 50~175 mg, 50~150 mg, 50~125 mg, 50~100 mg, 50~75 mg, 75~ 500 mg, 75~450 mg, 75~300 mg, 75~250 mg, 75~200 mg, 75~175 mg, 75~150 mg, 75~125 mg, 75~100 mg, 100~500 mg, 100~450 mg, 100~300 mg, 100~250 mg, 100~200 mg, 100~175 mg, 100~150 mg, 100~125 mg, 125~500 mg, 125~450 mg, 125~300 mg, 125~250 mg, 125~200 mg, 125~175 mg, 125-150 mg, 150-500 mg, 150-450 mg, 150-300 mg, 150-250 mg, 150-200 mg, 200-500 mg, 200-450 mg, 200-300 mg, 200-250 mg, 250-500 mg, 250-450 mg, 250-300 mg, 300-500 mg, 300-450 mg, 300-400 mg, 300-350 mg, 350-500 mg, 350-450 mg, 350-400 mg, 400-500 mg, 400-450 mg, and by way of example only, 0.01 mg, 0.025 mg, 0.05 mg, 0.075 mg, 0.1 mg, 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 125 mg, 150 mg 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, and 500 mg The composition may comprise, in an amount of about 100 mg, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof.

[0037] Typically, dosages may be administered to a subject with a seizure disorder 1, 2, 3 or 4 times per day, every other day, once per week, or once per month. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharmacologic acceptable salt thereof is administered to a subject with a seizure disorder at a dose of 0.01 to 50 mg per dose twice per day (e.g., morning and evening) or three times per day (e.g., breakfast, lunch, and dinner). In embodiments, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to a subject with a seizure disorder in one or more doses of 75 mg / day, 70 mg / day, 65 mg / day, 60 mg / day, 55 mg / day, 50 mg / day, 45 mg / day, 40 mg / day, 35 mg / day, 30 mg / day, 25 mg / day, 20 mg / day, 15 mg / day, 10 mg / day, 7.5 mg / day, 5.5 mg / day, 5 mg / day, 4.5 mg / day, 4 mg / day, 3.5 mg / day, 3 mg / day, 2.5 mg / day, 2 mg / day, 1.5 mg / day, 1 mg / day, 0.5 mg / day, 0.25 mg / day. In embodiments, the dosage for adults is about 0.5-50 mg / day, which can be increased up to 75 mg / day. Dosages can be lower for infants and children than for adults. In embodiments, the dosage for an infant or child is about 0.01-10 mg / day, which can be administered in a single dose or in 2, 3 or 4 divided doses. In embodiments, the pediatric dosage is 0.075 mg / kg / day to 1.0 mg / kg / day. In embodiments, subjects may be started on a lower dosage, and the dosage increased over time.

[0038] In an embodiment, a method for treating a seizure disorder is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for one hour or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for two hours or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for 3 hours or more after administration to the subject. In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for 4 hours or more after administration to the subject. In an embodiment, a method of treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the disorder for six hours or more after administration to the subject.In an embodiment, a method of treating a seizure disorder is provided, comprising administering a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof, wherein the pharmaceutical composition provides an improvement in one or more symptoms of the disorder for 8, 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration to the subject. In an embodiment, an improvement in at least one symptom is provided for 12 hours after administration of the pharmaceutical composition to the subject according to the present disclosure. In an embodiment, the pharmaceutical composition provides an improvement in the subject's next day functioning. For example, the pharmaceutical composition may provide an improvement in one or more symptoms of the disease for, for example, about 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours or more after administration and awakening from sleep.

[0039] In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof or a pharma-ceutically acceptable salt thereof is administered to a subject with a seizure disorder in combination with (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma-ceutically acceptable salt thereof. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma-ceutically acceptable salt thereof and (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma-ceutically acceptable salt thereof may be administered to a subject with a seizure disorder in separate dosage forms or combined in one dosage form. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, and (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid, or a pharma- ceutically acceptable salt thereof, may be administered simultaneously or at intervals to a subject with a seizure disorder.

[0040] In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or any pharma- ceutically acceptable salt thereof, after warning signs of an impending seizure have been detected to reduce or prevent seizure activity. In an embodiment, a method for treating a seizure disorder is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or any pharma- ceutically acceptable salt thereof, after warning signs of an impending seizure have been detected to reduce or prevent seizure activity. In embodiments, a continuous regimen of administration of the active agents herein ((S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or one or both of the pharma- ceutically acceptable salts of either of the foregoing) is effective to reduce or prevent the occurrence of seizure activity.

[0041] In an embodiment, the methods described herein are effective in reducing, delaying, or preventing one or more minor symptoms of a seizure disorder. For example, the effect of a composition comprising: 1. (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or any pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or any pharma- ceutically acceptable salt thereof, on a particular symptom, pharmacological, or physiological indicator, can be compared to an untreated subject, or to the condition of the subject prior to treatment. In an embodiment, the symptoms, pharmacological and / or physiological indicators are measured in the subject before treatment and again one or more times after treatment has begun. In an embodiment, the control is a reference level or an average determined based on measuring the symptoms, pharmacological or physiological indicators in one or more subjects (e.g., healthy subjects) that do not have the disease or condition to be treated. In an embodiment, the effect of the treatment is compared to conventional treatments known in the art.

[0042] Effective treatment of a seizure disorder (e.g., acute repetitive seizures, status epilepticus) herein may be established by demonstrating a reduction (e.g., 10%, 20%, 30% 40%, 50% or more) in the frequency or severity of symptoms after a period of time compared to baseline. For example, after a one-month baseline period, subjects can be randomly assigned to receive, as add-on therapy to standard therapy during a two-month double-blind period, 1. (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of any of the foregoing; or 2. (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of any of the foregoing; or placebo.

[0043] Primary outcome measures include the proportion of responders, defined as experiencing at least a 10% to 50% or greater reduction in symptoms at month 2 of the double-blind period compared to baseline, to: 1. (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of any of the foregoing; or 2. (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of any of the foregoing; and placebo.

[0044] In an embodiment, administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or any of the pharma- ceutically acceptable salts, alone or in combination, can be used to prevent epilepsy if administered before seizures appear in the subject.Detecting abnormal EEG signatures in a subject provides a modality for predicting the onset of epilepsy in a subject.For example, patients diagnosed with TSC are at high risk of developing epilepsy, including neurological disorders such as infantile spasms and cognitive impairment. Abnormal EEG signs such as multifocal spikes in infants diagnosed with TSC help identify candidates for anti-epileptic therapy with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- tically acceptable salt of any of the foregoing, alone or in any combination of one or more of the foregoing, performed before or immediately after a seizure occurs. In other words, anti-epileptic treatment at an early stage of epileptogenesis is initiated. In this way, the subject's neurological outcome is improved. Improved neurological outcome refers to the reduction or elimination of one or more symptoms associated with a seizure disorder. Thus, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, alone or in combination, or a pharma- ceutically acceptable salt of either of the foregoing, is used to treat abnormal EGG signs.

[0045] Provided herein are methods of treating Prader-Willi syndrome, which in embodiments include administering an effective amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In embodiments, the method of treating Prader-Willi syndrome includes administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in one or more symptoms of the syndrome. In embodiments, the method of treating Prader-Willi syndrome includes administering (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in the subject's next day functioning. In an embodiment, a method for treating Prader-Willi syndrome comprises administering an effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof. In an embodiment, a method for treating Prader-Willi syndrome comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in one or more symptoms of the syndrome. In an embodiment, a method for treating Prader-Willi syndrome comprises administering (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof to a subject in need thereof to provide an improvement in the subject's next day functioning. In an embodiment, a method for treating Prader-Willi syndrome comprises administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof.

[0046] Symptoms of Prader-Willi syndrome include hypotonia, difficulty sucking, difficulty feeding, poor muscle tone, growth hormone deficiency, low levels of sex hormones, constant hunger, excessive appetite (hypereating), weight gain, obesity, short stature, poor motor skills, underdeveloped genitals, intellectual disability, learning disabilities, delayed speech development, delayed language development, infertility, cognitive rigidity, cognitive impairment, emotional lability, obsessive-compulsive behavior, autistic symptoms, excessive daytime sleepiness, scoliosis, osteopenia / osteoporosis, slowed gastrointestinal motility, sleep disorders, and / or decreased pain sensitivity. Additionally, more severe psychiatric disorders may occur in approximately 10% of individuals with PWS, including psychotic episodes, bipolar disorder with depression and psychosis.

[0047] The DSM-5 provides criteria for specific learning disabilities that may be present in seizure disorders or Prader-Willi syndrome, which consider a specific learning disability to be a type of neurodevelopmental disorder that interferes with the ability to acquire or use specific academic skills (e.g., reading, writing, or arithmetic) that are fundamental to other learning.

[0048] Whether applied to a seizure disorder or Prader-Willi syndrome, cognitive impairment (aka impairment of cognition) may be measured relative to normal cognitive function, meaning normal physiological activity of the brain, such as, but not limited to, one or more of the following: mental stability, memory / recall ability, problem-solving ability, reasoning ability, thinking ability, judgment ability, discrimination or selection ability, learning ability, ease of learning, perception, intuition, attention, and consciousness, as measured by any standard appropriate in the art.

[0049] Cognitive impairment also includes mild impairment of mental activity or mental disorders that do not significantly interfere with daily life. Mild cognitive impairment (MCI) is an example of such a condition. Subjects with mild cognitive impairment may exhibit symptoms of dementia (e.g., language and memory difficulties), but the severity of these symptoms may not warrant a diagnosis of dementia.

[0050] Those skilled in the art will recognize that there are numerous human and animal models that can be used to assess and compare the relative safety and efficacy of the compounds described herein for the treatment of cognitive impairment associated with seizure disorders or Prader-Willi syndrome. In humans, cognitive function can be measured, for example, but not limited to, the Clinical Global Impression of Change scale (CGI); the Mini-Mental State Examination (MMSE) (also known as the Folstein test); the Neuropsychiatric Inventory (NPI); the Clinical Dementia Rating Scale (CDR); the Cambridge Neuropsychological Test Battery (CANTAB), the Sandoz Clinical Assessment-Geriatrics (SCAG) scale, the Benton Visual Retention Test (BVRT), the Montreal Cognitive Assessment (MoCA) or the Digit Symbol Substitution Test (DSST).

[0051] In animal model systems, cognitive function can be measured in a variety of conventional ways known in the art, including using the Morris Water Navigation Task, the Barnes Maze, the Radial Arm Maze Task, the T-Maze, etc. Other tests known in the art can also be used to assess cognitive function, such as novel object recognition and odor recognition tasks.

[0052] Cognitive function may also be measured using imaging techniques such as positron emission tomography (PET), functional magnetic resonance imaging (fMRI), single photon emission computed tomography (SPECT), or any other imaging technique that allows the measurement of brain function. In animals, cognitive function can also be measured with electrophysiological techniques.

[0053] Thus, an effective amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is used to treat a subject having Prader-Willi syndrome. An effective amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is used to treat a subject having Prader-Willi syndrome. The subject may be an animal, e.g., a mammal, e.g., a human. As used herein, the terms "treat", "treatment" or "treating", whether applied to a seizure disorder or Prader-Willi syndrome, encompass any manner in which the symptoms or pathology of a disorder or disease associated with a seizure disorder or Prader-Willi syndrome are ameliorated or otherwise beneficially altered. In an embodiment, "treat", "treatment" or "treating" may mean inhibiting a disease or condition, e.g., preventing or alleviating its onset or at least one clinical or subclinical symptom thereof. In embodiments, "treat", "treatment" or "treating" can mean alleviating a disease or condition, e.g., reversing a disease or condition or at least one of its clinical or asymptomatic symptoms. In embodiments, "treatment of cognitive impairment" means improving, beneficially altering, and / or alleviating one or more of the symptoms of cognitive impairment. The benefit to a subject being treated can be statistically significant, mathematically significant, or at least perceptible to the subject and / or physician.

[0054] In embodiments, the term "effective amount" or "therapeutically effective amount" as applied to PWS means an amount of a compound, material, composition, pharmaceutical, or other material effective to achieve a particular pharmacological and / or physiological effect in relation to PWS symptoms, such as, but not limited to, one or more of the following symptoms: reducing or eliminating sucking difficulties, reducing or eliminating feeding difficulties, reducing or eliminating poor muscle tone, reducing or eliminating growth hormone deficiency, reducing or eliminating low levels of sex hormones, reducing or eliminating constant hunger, reducing or eliminating excessive appetite (overeating), reducing or eliminating weight gain, reducing or eliminating obesity, reducing or eliminating short stature, reducing or eliminating poor motor skills, reducing or eliminating underdeveloped genitals, reducing or eliminating intellectual disability, reducing or eliminating learning disabilities, or or elimination, reduction or elimination of delayed speech development, reduction or elimination of delayed language development, reduction or elimination of infertility, reduction or elimination of cognitive rigidity, reduction or elimination of cognitive impairment, reduction or elimination of emotional lability, reduction or elimination of obsessive-compulsive behavior, reduction or elimination of autistic symptoms, reduction or elimination of psychotic episodes, reduction or elimination of bipolar disorder with psychosis, reduction or elimination of excessive daytime sleepiness, reduction or elimination of scoliosis, reduction or elimination of osteopenia / osteoporosis, reduction or elimination of slowed gastrointestinal motility, reduction or elimination of sleep disorders, and / or reduction or elimination of decreased pain sensitivity, improved cognitive function, increased daytime activity, improved learning (speed or ease of learning), improved attention, improved social behavior, and / or improved cerebrovascular function. In embodiments, effective amount refers to the amount that may be suitable for preventing the decline of any one or more of the above qualities, or in embodiments, for improving one or more of the above qualities, such as constant hunger, excessive appetite (hyperphagia), weight gain, obesity, cognitive function or performance, learning speed or ability, problem-solving ability, attention, attention span and ability to focus on a task or problem, social behavior, etc. In embodiments, effective amount may be suitable for reducing the degree or speed of the decline of appetite disorder, weight loss, cognitive ability or function of a subject, and / or effective amount may be suitable for delaying the onset of such decline.In embodiments, effective amount increases the BDNF expression in the hypothalamus.Such efficacy can be achieved, for example, by administering to an individual or population a composition described herein. The reduction, or delay in such decline, or amelioration, in an individual or population can be compared to a cohort, e.g., a control subject or cohort population that has not received the treatment or a cohort population that has been administered the composition or agent.

[0055] The dosage may vary depending on a variety of factors, such as subject-dependent variables (eg, age, immune system, health status, etc.), the disease or disorder being treated, as well as the route of administration and the pharmacokinetics of the agent being administered.

[0056] In an embodiment, the method includes treating PWS by administering about 0.1 mg to about 1500 mg of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as the hydrochloride salt, to a subject in need thereof. In an embodiment, the method includes treating PWS by administering about 0.5 mg to about 1000 mg of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as the hydrochloride salt, to a subject in need thereof. In an embodiment, the amount of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as the hydrochloride salt, for treating PWS can be between 0.1 and 1500 mg / day, or 0.01 mg / kg / day to 15 mg / kg / day. In an embodiment, the amount of (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, such as the hydrochloride salt thereof, for the treatment of PWS can be between 0.1 and 1000 mg / day. For example, the daily dosage may be, for example, about 0.1-1500 mg, 0.1-1250 mg, 0.1-1000 mg, 0.1-750 mg, 0.1-500 mg, 0.1-450 mg, 0.1-300 mg, 0.1-250 mg, 0.1-200 mg, 0.1-175 mg, 0.1-150 mg, 0.1-125 mg, 0.1-100 mg, 0.1-75 mg, 0.1-50 mg, 0.1-30 mg, 0.1-25 mg, 0.1-20 mg, 0.1-15 mg, 0.1-10 mg, 0.1-5 mg, 0.1-1 mg, 1-1500 mg, 1-1000 mg, 1-500 mg, 1-300 mg, 1-250 mg, 1-200 mg, mg, 1~175 mg, 1~150 mg, 1~125 mg, 1~100 mg, 1~75 mg, 1~50 mg, 1~30 mg, 1~25 mg, 1~20 mg, 1~15 mg, 1~10 mg, 1~5 mg, 5~1500 mg, 5~1000 mg, 5~500 mg, 5~300 mg, 5~250 mg, 5~200 mg, 5~175 mg, 5~150 mg, 5~125 mg, 5~100mg、5~75 mg、5~50 mg、5~30 mg、5~25 mg、5~20 mg、5~15 mg、5~10 mg、10~1500 mg、10~1000 mg、10~500 mg、10~300 mg、10~250 mg、10~200 mg、10~175 mg、10~150 mg、10~125 mg、10~100 mg、10~75 mg、10~50 mg、10~30 mg、10~25 mg、10~20 mg、10~15 mg、15~1500 mg、15~1000 mg、15~500 mg、15~300 mg、15~250 mg、15~200 mg、15~175 mg、15~150 mg、15~125 mg、15~100 mg、15~75 mg、15~50 mg、15~30 mg、15~25 mg、15~20 mg、20~1500 mg、20~1000 mg、20~500 mg、20~300 mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~1500 mg、25~1000 mg、25~500 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~75 mg、25~50 mg、25~30 mg、30~1500 mg、30~1000 mg、30~500 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、35~1500 mg、35~1000 mg、35~500 mg、35~300 mg、35~250 mg、35~200 mg、35~175 mg、35~150 mg、35~125 mg、35~100 mg、35~75 mg、35~50 mg、40~1500 mg、40~1000 mg、40~500 mg、40~300 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~1500mg, 50~1000 mg, 50~500 mg, 50~300 mg, 50~250 mg, 50~200 mg, 50~175 mg, 50~150 mg, 50~125 mg, 50~100 mg, 50~75 mg, 75~1500 mg, 75~1000 mg, 75~500 mg, 75~300 mg, 75~250 mg, 75~200 mg, 75~175 mg, 75~150 mg, 75~125 mg, 75~100 mg, 100~1500 mg, 100~1000 mg, 100~500 mg, 100~300 mg, 100~250 mg, 100~200 mg, 100~175 mg, 100~150 mg, 100~125 mg, 125~1500 mg, 125~1000 mg, 125~500 mg, 125~300 mg, 125~250 mg, 125~200 mg, 125~175 mg, 125~150 mg, 150~1500 mg, 150~1000 mg, 150~500 mg, 150~300 mg, 150~250 mg, 150~200 mg, 150~175 mg, 175~1500 mg, 175~1000 mg, 175~500 mg, 175~300 mg, 175~250 mg, 175~200 mg, 200~1500 mg, 200~1000 mg, 200~500 mg, 200~300 mg, 200~250 mg, 250-1500 mg, 250-1000 mg, 250-500 mg, 250-300 mg, 7.5-15 mg, 2.5-5 mg, 1-5 mg, as well as, for example, about 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 1.25 mg, 1.5 mg, 1.75 mg, 2.0 mg, 2.5 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 27.5 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 100 mg, 125 mg, 150 mg, 175 mg, 20 ... The dosages may be 225 mg, 250 mg, 275 mg, 300 mg, 400 mg and 500 mg.

[0057] For example, 0.01~500 mg、0.1~500 mg、0.1~450 mg、0.1~300 mg、0.1~250 mg、0.1~200 mg、0.1~175 mg、0.1~150 mg、0.1~125 mg、0.1~100 mg、0.1~75 mg、0.1~50 mg mg、0.1~30 mg、0.1~25 mg、0.1~20 mg、0.1~15 mg、0.1~10 mg、0.1~5 mg、0.1~1mg、0.5~ 500 mg、0.5~450 mg、0.5~300 mg、0.5~250 mg、0.5~200 mg、0.5~175 mg、0.5~150 mg mg、0.5~125 mg、0.5~100 mg、0.5~75 mg、0.5~50 mg、0.5~30 mg、0.5~25 mg、0.5~20 mg、0.5~15 mg、0.5~10 mg、0.5~5 mg、0.5~1mg、1~500 mg、1~450 mg、1~300 mg、1~250 mg、1~200 mg mg、1~175 mg、1~150 mg、1~125 mg、1~100 mg、1~75 mg、1~50 mg、1~30 mg、1~25 mg、1~20 mg、1~15 mg、1~10 mg、1~5 mg、5~ 500 mg、5~450 mg、5~300 mg、5~250 mg、5~200 mg、5~175 mg mg、5~150 mg、5~125 mg、5~100 mg、5~75 mg、5~50 mg、5~30 mg、5~25 mg、5~20 mg、5~15 mg、5~10 mg、10~500 mg、10~450 mg、10~300 mg、10~250 mg、10~200 mg、10~175 mg、10~150 mg、10~125 mg、10~100 mg、10~75 mg、10~50 mg、10~30 mg、10~25 mg、10~20 mg、10~15 mg、15~500 mg、15~450 mg、15~300 mg、15~250 mg、15~200 mg、15~175 mg、15~150 mg、15~125 mg、15~100 mg、15~75 mg、15~50 mg、15~30 mg、15~25 mg、15~20 mg、20~500 mg、20~450 mg、20~300mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~500 mg、25~450 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~80 mg、25~75 mg、25~50 mg、25~30 mg、30~500 mg、30~450 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、40~500 mg、40~450 mg、40~400 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~500 mg、50~450 mg、50~300 mg、50~250 mg、50~200 mg、50~175 mg、50~150 mg、50~125 mg、50~100 mg、50~75 mg、75~ 500 mg、75~450 mg、75~300 mg、75~250 mg、75~200 mg、75~175 mg、75~150 mg、75~125 mg、75~100 mg、100~500 mg、100~450 mg、100~300 mg、100~250 mg、100~200 mg、100~175 mg、100~150 mg、100~125 mg、125~500 mg、125~450 mg、125~300 mg、125~250 mg、125~200 mg、125~175 mg、125~150 mg、150~500 mg、150~450 mg、150~300 mg、150~250 mg、150~200 mg、200~500 mg、200~450 mg、200~300 mg、200~250 mg、250~500 mg、250~450 mg、250~300 mg、300~500 mg、300~450 mg、300~400 mg、300~350 mg、350~500 mg、350~450mg, 350-400 mg, 400-500 mg, 400-450 mg, and by way of example only, 0.1 mg, 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 125 mg, 150 mg 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, and 500 mg. mg, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof.

[0058] Typically, dosages for treating PWS may be administered 1, 2, 3 or 4 times daily, every other day, once a week, or once a month. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharmacologiciZably acceptable salt thereof is administered to a subject at a dose of 1-50 mg per administration tWice a day (e.g., morning and evening) or three times a day (e.g., breakfast, lunch, and dinner). In embodiments, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof is administered to a subject in one or more doses of 100 mg / day, 95 mg / day, 90 mg / day, 85 mg / day, 80 mg / day, 75 mg / day, 70 mg / day, 65 mg / day, 60 mg / day, 55 mg / day, 50 mg / day, 45 mg / day, 40 mg / day, 35 mg / day, 30 mg / day, 25 mg / day, 20 mg / day, 15 mg / day, 10 mg / day, 5 mg / day, 4 mg / day, 3 mg / day, 2 mg / day, 1 mg / day. In embodiments, adult doses for treating PWS range from about 5 to 80 mg / day, and can be increased up to 150 mg / day. Dosages can be lower for infants and children than for adults. In embodiments, an infant or child dose for treating PWS is about 0.1 to 50 mg / day, which can be administered in a single dose or in 2, 3 or 4 divided doses. In embodiments, a pediatric dose for treating PWS is 0.75 mg / kg / day to 1.5 mg / kg / day. In embodiments, subjects may be started on a lower dose and the dosage increased over time.

[0059] In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof is administered via a pharmaceutical composition for the treatment of either seizure disorder or PWS. The pharmaceutical composition herein includes dosage forms. The dosage forms herein include unit doses. In an embodiment, various dosage forms, such as conventional formulations and modified release formulations, can be administered one or more times a day, as described below. Any suitable route of administration can be utilized, such as oral, rectal, nasal, pulmonary, vaginal, sublingual, transdermal, intravenous, intraarterial, intramuscular, intraperitoneal, and subcutaneous routes. Suitable dosage forms include tablets, capsules, oral liquids, powders, aerosols, topical liquids, patches, transdermal formulations such as creams and ointments, parenteral formulations, and suppositories.

[0060] In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for one hour or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for two hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for three hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for 4 hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for 6 hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides an improvement in one or more symptoms of the syndrome for 8, 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration to the subject. In an embodiment, the pharmaceutical composition provides an improvement in the subject's next day functioning.For example, the pharmaceutical composition may provide improvement in one or more symptoms of the syndrome for, e.g., about 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours or more after administration and awakening from sleep.

[0061] In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof or a pharma- ceutically acceptable salt thereof is administered to a subject with PWS in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof may be administered to a subject with PWS in separate dosage forms or combined in one dosage form. In an embodiment, (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid, or a pharma- ceutically acceptable salt thereof, and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, may be administered simultaneously or at intervals to a subject with PWS.

[0062] In an embodiment, the method includes treating PWS by administering about 0.005 mg to about 750 mg of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, e.g., hydrochloride, to a subject in need thereof. In an embodiment, the amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, e.g., hydrochloride, for treating PWS can be between 0.005 and 1000 mg / day, or 0.005 mg / kg / day to 14 mg / kg / day. For example, the daily dosage may be, for example, about 0.01-750 mg, 0.01-700 mg, 0.01-500 mg, 0.01-250 mg, 0.01-200 mg, 0.01-175 mg, 0.01-150 mg, 0.01-125 mg, 0.01-100 mg, 0.01-75 mg, 0.01-50 mg, 0.01-30 mg, 0.01-25 mg, 0.01-20 mg, 0.01-15 mg, 0.01-10 mg, 0.01-5 mg, 0.01-4 mg, 0.01-3 mg, 0.01-2 mg, 0.01-1 mg, 0.01-0.75 mg, 0.01-0.5 mg, 0.01-0.25 mg, 0.01-0.1 mg, 0.1~750 mg, 0.1~700 mg, 0.1~500 mg, 0.1~250 mg, 0.1~200 mg, 0.1~175 mg, 0.1~150 mg, 0.1~125 mg, 0.1~100 mg, 0.1~75 mg, 0.1~50 mg, 0.1~30 mg, 0.1~25 mg, 0.1~20 mg, 0.1~15 mg, 0.1~10 mg, 0.1~5 mg, 0.1~4 mg, 0.1~3 mg, 0.1~2 mg, 0.1~1 mg, 0.1~0.75 mg, 0.1~0.5 mg, 0.1~0.25 mg, 0.25~750 mg, 0.25~700 mg, 0.25~500 mg, 0.25~250 mg, 0.25~200 mg, 0.25~175 mg, 0.25~150 mg, 0.25~125 mg, 0.25~100 mg, 0.25~75 mg, 0.25~50 mg, 0.25~30 mg, 0.25~25 mg, 0.25~20 mg, 0.25~15 mg、0.25~10 mg、0.25~5 mg、0.25~4 mg、0.25~3 mg、0.25~2 mg、0.25~1 mg、0.25~0.75 mg、0.25~0.5 mg、0.3~750 mg、0.5~700 mg、0.3~500 mg、0.3~250 mg、0.3~200 mg、0.3~175 mg、0.3~150 mg、0.3~125 mg、0.3~100 mg、0.3~75 mg、0.3~50 mg、0.3~30 mg、0.3~25 mg、0.3~20 mg、0.3~15 mg、0.3~10 mg、0.3~5 mg、0.3~4 mg、0.3~3 mg、0.3~2 mg、0.3~1 mg、0.3~0.75 mg、0.3~0.5 mg,0.4~750 mg、0.4~700 mg、0.4~500 mg、0.4~250 mg、0.4~200 mg、0.4~175 mg、0.4~150 mg、0.4~125 mg、0.4~100 mg、0.4~75 mg、0.4~50 mg、0.4~30 mg、0.4~25 mg、0.4~20 mg、0.4~15 mg、0.4~10 mg、0.4~5 mg、0.4~4 mg、0.4~3 mg、0.4~2 mg、0.4~1 mg、0.4~0.75 mg、0.4~0.5 mg,0.5~750 mg、0.5~700 mg、0.5~500 mg、0.5~250 mg、0.5~200 mg、0.5~175 mg、0.5~150 mg、0.5~125 mg、0.5~100 mg、0.5~75 mg、0.5~50 mg、0.5~30 mg、0.5~25 mg、0.5~20 mg、0.5~15 mg、0.5~10 mg、0.5~5 mg、0.5~4 mg、0.5~3 mg、0.5~2 mg、0.5~1 mg、0.5~0.75 mg、0.75~750 mg、0.75~700 mg、0.75~500 mg、0.75~250 mg、0.75~200 mg、0.75~175 mg、0.75~150 mg、0.75~125 mg、0.75~100 mg、0.75~75 mg、0.75~50 mg、0.75~30 mg、0.75~25 mg、0.75~20 mg、0.75~15 mg、0.75~10 mg、0.75~5 mg、0.75 - 4 mg, 0.75 - 3 mg, 0.75 - 2 mg, 0.75 - 1 mg, 1 - 750 mg, 1 - 700 mg, 1 - 500 mg, 1 - 250 mg, 1 - 200 mg, 1 - 175 mg, 1 - 150 mg, 1 - 125 mg, 1 - 100 mg, 1 - 75 mg, 1 - 50 mg, 1 - 30 mg, 1 - 25 mg, 1 - 20 mg, 1 - 15 mg, 1 - 10 mg, 1 - 5 mg, 1 - 4 mg, 1 - 3 mg, 1 - 2 mg, 2 - 750 mg, 2 - 700 mg, 2 - 500 mg, 2 - 250 mg, 2 - 200 mg, 2 - 175 mg, 2 - 150 mg, 2 - 125 mg, 2 - 100 mg, 2 - 75 mg, 2 - 50 mg, 2 - 30 mg, 2 - 25 mg, 2 - 20 mg, 2 - 15 mg, 2 - 10 mg, 2 - 5 mg, 2 - 4 mg, 2 - 3 mg, 3 - 750 mg, 3 - 700 mg, 3 - 500 mg, 3 - 250 mg, 3 - 200 mg, 3 - 175 mg, 3 - 150 mg, 3 - 125 mg, 3 - 100 mg, 3 - 75 mg, 3 - 50 mg, 3 - 30 mg, 3 - 25 mg, 3 - 20 mg, 3 - 15 mg, 3 - 10 mg, 3 - 5 mg, 3 - 4 mg, 4 - 750 mg, 4 - 700 mg, 4 - 500 mg, 4 - 250 mg, 4 - 200 mg, 4 - 175 mg, 4 - 150 mg, 4 - 125 mg, 4 - 100 mg, 4 - 75 mg, 4 - 50 mg, 4 - 30 mg, 4 - 25 mg, 4 - 20 mg, 4 - 15 mg, 4 - 10 mg, 4 - 5 mg, 5 - 750 mg, 5 - 700 mg, 5 - 500 mg, 5 - 250 mg, 5 - 200 mg, 5 - 175 mg, 5 - 150 mg, 5 - 125 mg, 5 - 100 mg, 5 - 75 mg, 5 - 50 mg, 5 - 30 mg, 5 - 25 mg, 5 - 20 mg, 5 - 15 mg, 5 - 10 mg, 7.5 - 15 mg, 2.5 - 5 mg ranges, and by way of example, for example, about 0.01 mg, 0.025 mg, 0.05 mg, 0.075 mg, 0.1 mg, 0.2 mg, 0.25 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.75 mg, 1 mg, 1.25 mg, 1.5 mg, 1.75 mg, 2.0 mg, 2.5 mg, 3.0 mg, 3.5 mg, 4.0 mg, 4.Doses of 5 mg, 5 mg, 6 mg, 7 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 27.5 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 75 mg, 100 mg, 125 mg, 150 mg, 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 400 mg and 500 mg.

[0063] In an embodiment, the pharmaceutical composition may be, for example, about 0.001-500 mg, 0.01-500 mg, 0.01-450 mg, 0.01-300 mg, 0.01-250 mg, 0.01-200 mg, 0.01-175 mg, 0.01-150 mg, 0.01-125 mg, 0.01-100 mg, 0.01-75 mg, 0.01-50 mg, 0.01-30 mg, 0.01-25 mg, 0.01-20 mg, 0.01-15 mg, 0.01-10 mg, 0.01-5 mg, 0.01-1 mg, 0.025-500 mg, 0.025-450 mg, 0.025-300 mg, 0.025-250 mg, 0.025-200 mg, mg, 0.025~175 mg, 0.025~150 mg, 0.025~125 mg, 0.025~100 mg, 0.025~75 mg, 0.025~50 mg, 0.025~30 mg, 0.025~25 mg, 0.025~20 mg, 0.025~15 mg, 0.025~10 mg, 0.025~5 mg, 0.025~1 mg, 0.05~500 mg, 0.05~450 mg, 0.05~300 mg, 0.05~250 mg, 0.05~200 mg, 0.05~175 mg, 0.05~150 mg, 0.05~125 mg, 0.05~100 mg, 0.05~75 mg, 0.05~50 mg, 0.05~30 mg, 0.05~25 mg, 0.05~20 mg, 0.05~15 mg, 0.05~10 mg, 0.05~5 mg, 0.05~1 mg, 0.075~500 mg, 0.075~450 mg, 0.075~300 mg, 0.075~250 mg, 0.075~200 mg, 0.075~175 mg, 0.075~150 mg, 0.075~125 mg, 0.075~100 mg, 0.075~75 mg, 0.075~50 mg, 0.075~30 mg, 0.075~25 mg, 0.075~20 mg, 0.075~15 mg, 0.075~10 mg, 0.075~5 mg, 0.075~1mg, 0.1~500 mg, 0.1~450 mg, 0.1~300 mg, 0.1~250 mg, 0.1~200 mg, 0.1~175 mg, 0.1~150 mg, 0.1~125 mg, 0.1~100 mg, 0.1~75 mg, 0.1~50mg、0.1~30 mg、0.1~25 mg、0.1~20 mg、0.1~15 mg、0.1~10 mg、0.1~5 mg、0.1~1mg、0.25~500 mg、0.25~450 mg、0.25~300 mg、0.25~250 mg、0.25~200 mg、0.25~175 mg、0.25~150 mg、0.25~125 mg、0.25~100 mg、0.25~75 mg、0.25~50 mg、0.25~30 mg、0.25~25 mg、0.25~20 mg、0.25~15 mg、0.25~10 mg、0.25~5 mg、0.25~1mg、0.05~500 mg、0.5~450 mg、0.5~300 mg、0.5~250 mg、0.5~200 mg、0.5~175 mg、0.5~150 mg、0.5~125 mg、0.5~100 mg、0.5~75 mg、0.5~50 mg、0.5~30 mg、0.5~25 mg、0.5~20 mg、0.5~15 mg、0.5~10 mg、0.5~5 mg、0.5~1mg、1~500 mg、1~450 mg、1~300 mg、1~250 mg、1~200 mg、1~175 mg、1~150 mg、1~125 mg、1~100 mg、1~75 mg、1~50 mg、1~30 mg、1~25 mg、1~20 mg、1~15 mg、1~10 mg、1~5 mg、1~4 mg、1~3 mg、1~2 mg、2~500 mg、2~450 mg、2~300 mg、2~250 mg、2~200 mg、2~175 mg、2~150 mg、2~125 mg、2~100 mg、2~75 mg、2~50 mg、2~30 mg、2~25 mg、2~20 mg、2~15 mg、2~10 mg、2~5 mg、3~500 mg、3~450 mg、3~300 mg、3~250 mg、3~200 mg、3~175 mg、3~150 mg、3~125 mg、3~100 mg、3~75 mg、3~50 mg、3~30 mg、3~25 mg、3~20 mg、3~15 mg、3~10 mg、3~5 mg、4~500 mg、4~450 mg、4~300 mg、4~250 mg、4~200 mg、4~175 mg、4~150 mg、4~125 mg、4~100 mg、4~75mg、4~50 mg、4~30 mg、4~25 mg、4~20 mg、4~15 mg、4~10 mg、4~5 mg、5~500 mg、5~450 mg、5~300 mg、5~250 mg、5~200 mg、5~175 mg、5~150 mg、5~125 mg、5~100 mg、5~75 mg、5~50 mg、5~30 mg、5~25 mg、5~20 mg、5~15 mg、5~10 mg、10~500 mg、10~450 mg、10~300 mg、10~250 mg、10~200 mg、10~175 mg、10~150 mg、10~125 mg、10~100 mg、10~75 mg、10~50 mg、10~30 mg、10~25 mg、10~20 mg、10~15 mg、15~500 mg、15~450 mg、15~300 mg、15~250 mg、15~200 mg、15~175 mg、15~150 mg、15~125 mg、15~100 mg、15~75 mg、15~50 mg、15~30 mg、15~25 mg、15~20 mg、20~500 mg、20~450 mg、20~300 mg、20~250 mg、20~200 mg、20~175 mg、20~150 mg、20~125 mg、20~100 mg、20~75 mg、20~50 mg、20~30 mg、20~25 mg、25~500 mg、25~450 mg、25~300 mg、25~250 mg、25~200 mg、25~175 mg、25~150 mg、25~125 mg、25~100 mg、25~80 mg、25~75 mg、25~50 mg、25~30 mg、30~500 mg、30~450 mg、30~300 mg、30~250 mg、30~200 mg、30~175 mg、30~150 mg、30~125 mg、30~100 mg、30~75 mg、30~50 mg、40~500 mg、40~450 mg、40~400 mg、40~250 mg、40~200 mg、40~175 mg、40~150 mg、40~125 mg、40~100 mg、40~75 mg、40~50 mg、50~500 mg、50~450 mg、50~300 mg、50~250 mg、50~200 mg、50~175mg, 50~150 mg, 50~125 mg, 50~100 mg, 50~75 mg, 75~ 500 mg, 75~450 mg, 75~300 mg, 75~250 mg, 75~200 mg, 75~175 mg, 75~150 mg, 75~125 mg, 75~100 mg, 100~500 mg, 100~450 mg, 100~300 mg, 100~250 mg, 100~200 mg, 100~175 mg, 100~150 mg, 100~125 mg, 125~500 mg, 125~450 mg, 125~300 mg, 125~250 mg, 125~200 mg, 125~175 mg, 125~150 mg, 150-500 mg, 150-450 mg, 150-300 mg, 150-250 mg, 150-200 mg, 200-500 mg, 200-450 mg, 200-300 mg, 200-250 mg, 250-500 mg, 250-450 mg, 250-300 mg, 300-500 mg, 300-450 mg, 300-400 mg, 300-350 mg, 350-500 mg, 350-450 mg, 350-400 mg, 400-500 mg, 400-450 mg, and by way of example only, 0.01 mg, 0.025 mg, 0.05 mg, 0.075 mg, 0.1 mg, 0.25 mg, 0.5 mg, 0.75 mg, 1 mg, 25 mg, 25 mg, 30 ... In some embodiments, the compound may contain (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof in the amount of, for example, 1 mg, 2 mg, 2.5 mg, 3 mg, 4 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, 15 mg, 17.5 mg, 20 mg, 22.5 mg, 25 mg, 30 mg, 35 mg, 40 mg, 45 mg, 50 mg, 55 mg, 60 mg, 65 mg, 70 mg, 75 mg, 80 mg, 85 mg, 90 mg, 95 mg, 100 mg, 125 mg, 150 mg 175 mg, 200 mg, 225 mg, 250 mg, 275 mg, 300 mg, 325 mg, 350 mg, 375 mg, 400 mg, 425 mg, 450 mg, 475 mg, and 500 mg.

[0064] Typically, dosages can be administered 1, 2, 3 or 4 times daily, every other day, once a week, or once a month. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to a subject at a dose of 0.01-50 mg / dose twice a day (e.g., morning and evening) or three times a day (e.g., breakfast, lunch, and dinner). In embodiments, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to a subject in one or more doses of 75 mg / day, 70 mg / day, 65 mg / day, 60 mg / day, 55 mg / day, 50 mg / day, 45 mg / day, 40 mg / day, 35 mg / day, 30 mg / day, 25 mg / day, 20 mg / day, 15 mg / day, 10 mg / day, 7.5 mg / day, 5.5 mg / day, 5 mg / day, 4.5 mg / day, 4 mg / day, 3.5 mg / day, 3 mg / day, 2.5 mg / day, 2 mg / day, 1.5 mg / day, 1 mg / day, 0.5 mg / day, 0.25 mg / day. In embodiments, the adult dosage for treating PWS is about 0.5-50 mg / day, which can be increased up to 75 mg / day. Dosages can be lower for infants and children than for adults. In embodiments, the infant or child dosage for treating PWS is about 0.01-10 mg / day, which can be administered in a single dose or in 2, 3 or 4 divided doses. In embodiments, the pediatric dosage for treating PWS is 0.075 mg / kg / day to 50 mg / kg / day. In embodiments, subjects may be started on a lower dosage, and the dosage increased over time.

[0065] In an embodiment, for the treatment of either seizure disorder or PWS, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered via a pharmaceutical composition. The pharmaceutical composition herein includes dosage forms. The dosage forms herein include unit doses. In an embodiment, various dosage forms, such as conventional and modified release formulations, can be administered one or more times a day, as described below. Any suitable route of administration can be utilized, such as oral, rectal, nasal, pulmonary, vaginal, sublingual, transdermal, intravenous, intraarterial, intramuscular, intraperitoneal, and subcutaneous routes. Suitable dosage forms include tablets, capsules, oral liquids, powders, aerosols, topical liquids, patches, transdermal formulations such as creams and ointments, parenteral formulations, and suppositories.

[0066] In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for one hour or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for two hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for 3 hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for 4 hours or more after administration to the subject. In an embodiment, a method of treating PWS is provided comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides improvement in one or more symptoms of the syndrome for six hours or more after administration to the subject.In an embodiment, a method of treating PWS is provided, comprising administering to a subject in need thereof a pharmaceutical composition comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, wherein the pharmaceutical composition provides an improvement in one or more symptoms of the syndrome for 8, 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration to the subject. In an embodiment, the pharmaceutical composition provides an improvement in the subject's next day functioning. For example, the pharmaceutical composition may provide an improvement in one or more symptoms of the syndrome for, for example, about 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours or more after administration and awakening from sleep.

[0067] In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof or a pharma- ceutically acceptable salt thereof is administered to a subject with PWS in combination with (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof and (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid or a pharma- ceutically acceptable salt thereof may be administered to a subject with PWS in separate dosage forms or combined in one dosage form. In an embodiment, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, and (1S,3S)-3-amino-4-difluoromethylenyl-1-cyclopentanoic acid, or a pharma- ceutically acceptable salt thereof, may be administered simultaneously or at intervals to a subject with PWS.

[0068] In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (1S,3S)- The in vivo plasma profile in the subject 10 hours after administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof in combination with 3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing is reduced by 50% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration. In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, wherein the (1S, The in vivo plasma profile in the subject 10 hours after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with 3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt of either of the foregoing, is reduced by 50% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration.

[0069] In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (1S,3S)- The in vivo plasma profile in the subject 10 hours after administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof in combination with 3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing is reduced by 55% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration. In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, alone or in combination, provides a The in vivo plasma profile in the subject 10 hours after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with 1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, is reduced by 55% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration.

[0070] In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (1S,3S)- The in vivo plasma profile in the subject 10 hours after administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof in combination with 3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing is reduced by 60% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration. In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, alone or in combination, provides a The in vivo plasma profile in the subject 10 hours after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with 1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, is reduced by 60% or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration.

[0071] In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (1S,3S)- The in vivo plasma profile in the subject 10 hours after administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt thereof in combination with 3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing is reduced by 65% ​​or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration. In an embodiment, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, which provides an in vivo plasma profile, wherein the (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, alone or in combination with (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a pharma- ceutically acceptable salt of either of the foregoing, alone or in combination, provides a The in vivo plasma profile in the subject 10 hours after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, in combination with 1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or a pharma- ceutically acceptable salt thereof, is reduced by 65% ​​or more, and the method provides an improvement in the subject for 10, 12, 14, 16, 18, 20, 22, or 24 hours or more after administration.

[0072] In embodiments, provided herein are methods for treating PWS or a seizure disorder, wherein the amount of an active agent, e.g., (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, individually or in combination, in a subject about 4 hours after administration of the pharmaceutical composition is less than about 75% of the administered amount. In embodiments, the present disclosure provides a method, wherein the amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, individually or in any combination, in a subject about 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, or 20 hours after administration of the pharmaceutical composition is less than about 75% of the administered amount.

[0073] In embodiments, provided herein are methods for treating PWS or a seizure disorder, wherein the amount of an active agent, e.g., (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, individually or in combination, in a subject about 4 hours after administration of the pharmaceutical composition is less than about 80% of the administered amount. In embodiments, the present disclosure provides a method, wherein the amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, individually or in any combination, in a subject about 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, or 20 hours after administration of the pharmaceutical composition is less than about 80% of the administered amount.

[0074] In an embodiment, the present disclosure provides a method for treating PWS or a seizure disorder, wherein the amount of an active agent, e.g., (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, individually or in combination, in a subject about 4 hours after administration of the pharmaceutical composition is between about 65% and about 85% of the administered amount. In embodiments, the present disclosure provides methods, wherein the amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, individually or in any combination, in a subject about 6, 8, 10, 12, 15, or 20 hours after administration of the pharmaceutical composition is between about 65% and about 85% of the administered amount.

[0075] In embodiments, the pharmaceutical compositions described herein may be administered once a day, twice a day, three times a day, four times a day, or every other day. In embodiments, the pharmaceutical compositions described herein may be administered by continuous infusion. In embodiments, the pharmaceutical compositions described herein are provided to a subject in the morning. In embodiments, the pharmaceutical compositions described herein are provided to a subject in the evening. In embodiments, the pharmaceutical compositions described herein are provided to a subject once in the evening and once in the morning. In embodiments, the pharmaceutical compositions described herein are provided to a subject once in the morning, once in the afternoon, and once in the evening.

[0076] In embodiments, as mentioned above, the pharmaceutical compositions herein may be provided with conventional or modified release profiles. Pharmaceutical compositions may be prepared using pharma- ceutically acceptable "carriers" that are composed of materials that are deemed safe and effective. "Carriers" include all ingredients present in pharmaceutical formulations other than the active ingredient. The term "carrier" includes, but is not limited to, diluents, binders, lubricants, disintegrants, fillers, and coating compositions. Those skilled in the art are familiar with such pharmaceutical carriers and methods of formulating pharmaceutical compositions using such carriers.

[0077] In an embodiment herein, the pharmaceutical composition is a modified release dosage form that modifies the release profile. The modified release profile may exhibit an immediate release, delayed release, or sustained release profile. Conventional (or unmodified) release oral dosage forms, such as tablets, capsules, suppositories, syrups, solutions, and suspensions, typically release drug to the mouth, stomach, or intestines when the tablet, capsule shell, or suppository dissolves, or in the case of syrups, solutions, and suspensions, when they are swallowed. The pattern of drug release from modified release (MR) dosage forms is purposefully altered from that of conventional dosage forms to achieve a desired therapeutic objective and / or better patient compliance. Types of MR pharmaceutical products include orally disintegrating dosage forms (ODDFs) that provide immediate release, sustained release, delayed release (e.g., enteric coated), and pulsatile release dosage forms.

[0078] ODDFs are solid dosage forms containing medicinal substances or active ingredients that disintegrate rapidly when placed on the tongue, usually within a few seconds. The disintegration time of ODDFs generally ranges from one or two seconds to about one minute. ODDFs are designed to disintegrate or dissolve rapidly upon contact with saliva. This method of administration is beneficial for people who have problems swallowing tablets, whether due to physical frailty or psychiatric reasons. Subjects with PWS or seizure disorders may exhibit such behavior. ODDFs can rapidly deliver drugs through the mucosa into the bloodstream, resulting in a rapid onset of action. Examples of ODDFs include orally disintegrating tablets, capsules, and fast-dissolving films and wafers.

[0079] An extended release dosage form (ERDF) is one that has an extended release profile and can be administered less frequently compared to that offered by conventional dosage forms, such as solutions or unmodified release dosage forms. An ERDF provides a sustained duration of action of the drug. Suitable formulations that provide an extended release profile are well known in the art. For example, coated delayed release beads or granules (beads and granules are used interchangeably) in which one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the above, are applied to beads, such as confectioner's nonpareil beads, and then coated with conventional release-retarding materials, such as wax, enteric coating, etc. In an embodiment, one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, may be mixed with materials to form beads that provide a mass from which the drug can be leached. In an embodiment, beads may be engineered to provide different release rates by using different materials to vary the coating or mass characteristics, e.g., thickness, porosity. Beads with different release rates may be combined into a single dosage form to provide variable or continuous release. Beads may be placed in capsules or compressed into tablets.

[0080] In an embodiment, the modified dosage form herein includes a delayed release dosage form having a delayed release profile. The delayed release dosage form includes a delayed release tablet or a delayed release capsule. A delayed release tablet is a solid dosage form that releases one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the above, at a time other than immediately after administration. A delayed release capsule is a solid dosage form in which a drug is enclosed in a hard or soft soluble container made of gelatin in a suitable form, and the drug is released at a time other than immediately after administration. For example, enteric-coated tablets, capsules, particles and beads are well-known examples of delayed release dosage forms. Enteric-coated tablets, capsules, particles and beads pass through the stomach and release the drug in the intestine. In an embodiment, a delayed release tablet is a solid dosage form comprising an agglomerate of medicinal particles that releases drug at a time other than immediately after administration. In an embodiment, the agglomerate of medicinal particles is covered with a coating that delays the release of the drug. In an embodiment, a delayed release capsule is a solid dosage form comprising an agglomerate of medicinal particles that releases drug at a time other than immediately after administration. In an embodiment, the agglomerate of medicinal particles is covered with a coating that delays the release of the drug.

[0081] Delayed release dosage forms are known to those skilled in the art. For example, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115) or both, or any pharma- ceutically acceptable salt of the above, is applied to beads, such as confectioner's nonpareil beads, and then coated with conventional release-retarding materials, such as wax, enteric coating, etc. In an embodiment, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115) or both, or any pharma-ceutically acceptable salt of the above, can be mixed with materials to form beads that provide a mass from which the drug is leached. In embodiments, the beads can be engineered to provide different release rates by varying the coating or mass characteristics, e.g., thickness, porosity, with different materials. In embodiments, the enteric coated granules of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, can be included in an enteric coated capsule or tablet that releases the granules in the small intestine. In embodiments, the granules are coated and remain so until the coated granules reach at least the ileum, after which a delayed release of the drug in the colon is provided. Suitable enteric coating materials are well known in the art, for example, Eudragit® coatings, such as methacrylic acid and methyl methacrylate polymers. The granules can be placed in capsules or compressed into tablets.

[0082] In an embodiment, one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, are incorporated into a porous inert carrier that provides a delayed release profile. In an embodiment, the porous inert carrier incorporates channels or passages through which the drug diffuses into the surrounding fluid. In an embodiment, one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, are incorporated into an ion exchange resin that provides a delayed release profile. When the drug-resin complex comes into contact with gastrointestinal fluids and ionic components dissolved therein, a delayed effect may result from a predetermined release rate of the drug from the resin. In an embodiment, a membrane is utilized to control the release rate from a drug-containing reservoir. In an embodiment, a liquid formulation may also be utilized to provide a delayed release profile. For example, a liquid formulation consisting of solid particles dispersed throughout a liquid phase in which the particles are insoluble. Suspensions are formulated to at least allow for reduced dosing frequency compared to drugs presented as conventional dosage forms (e.g., solutions, or conventional solid dosage forms for rapid drug release). For example, suspensions of ion exchange resin components or microbeads.

[0083] In embodiments, the pharmaceutical compositions described herein are suitable for parenteral administration, such as, for example, intramuscular (im), intravenous (iv), subcutaneous (sc), intraperitoneal (ip), or intrathecal (it). Parenteral compositions must be sterile for administration by injection, infusion, or implantation into the body, and may be packaged in either single-dose or multi-dose containers. In embodiments, liquid pharmaceutical compositions for parenteral administration to a subject contain any of the above respective amounts of an active agent, such as, for example, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutical acceptable salt of any of the foregoing. In an embodiment, the pharmaceutical composition for parenteral administration is formulated in a total volume of about 10 ml, 20 ml, 25 ml, 50 ml, 100 ml, 200 ml, 250 ml, or 500 ml. In an embodiment, the composition is contained in a bag, glass vial, plastic vial, or bottle.

[0084] In an embodiment, the pharmaceutical composition for parenteral administration contains the respective amounts of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing. In an embodiment, the pharmaceutical composition for parenteral administration contains about 0.05 mg to about 500 mg of an active substance, for example, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing. In an embodiment, a pharmaceutical composition for parenteral administration to a subject comprises an active agent, e.g., (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, in a concentration of about 0.005 mg / ml to about 500 mg / ml, respectively. In an embodiment, a pharmaceutical composition for parenteral administration comprises (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, at a concentration of, for example, about 0.05 mg / ml to about 50 mg / ml, about 0.1 mg / ml to about 50 mg / ml, about 0.1 mg / ml to about 10 mg / ml, about 0.05 mg / ml to about 25 mg / ml, about 0.05 mg / ml to about 10 mg / ml, about 0.05 mg / ml to about 5 mg / ml, or about 0.05 mg / ml to about 1 mg / ml, respectively.In embodiments, a pharmaceutical composition for parenteral administration comprises (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, at a concentration of, for example, about 0.05 mg / ml to about 15 mg / ml, about 0.5 mg / ml to about 10 mg / ml, about 0.25 mg / ml to about 5 mg / ml, about 0.5 mg / ml to about 7 mg / ml, about 1 mg / ml to about 10 mg / ml, about 5 mg / ml to about 10 mg / ml, or about 5 mg / ml to about 15 mg / ml, respectively.

[0085] In an embodiment, a pharmaceutical composition for parenteral administration is provided, wherein the pharmaceutical composition is stable for at least 6 months. In an embodiment, the pharmaceutical composition for parenteral administration shows, for example, a decrease of about 5% or less in the amount of active substance, for example, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or any pharma- ceutically acceptable salt thereof, for example, for 3 or 6 months. In an embodiment, the amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or any pharma- ceutically acceptable salt thereof, for example, decreases by about 2.5%, 1%, 0.5%, or 0.1% or less. In embodiments, the decrease is, for example, less than about %5, 2.5%, 1%, 0.5%, 0.25%, 0.1% for at least 6 months.

[0086] In embodiments, pharmaceutical compositions for parenteral administration are provided in which the pharmaceutical composition remains soluble. In embodiments, pharmaceutical compositions for parenteral administration are provided that are stable, soluble, locally compatible and / or ready to use. In embodiments, the pharmaceutical compositions described herein are ready to use for direct administration to a subject in need thereof.

[0087] The pharmaceutical compositions for parenteral administration provided herein may include one or more excipients, such as solvents, dissolution enhancers, suspending agents, buffers, isotonicity agents, stabilizers or antimicrobial preservatives. When used, the excipients of the parenteral composition do not adversely affect the stability, bioavailability, safety and / or efficacy of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or any pharma- ceutically acceptable salt thereof, used in the composition. Thus, a parenteral composition is provided that is not incompatible with any of the components of the dosage form.

[0088] In an embodiment, the parenteral composition comprising (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, comprises a stabilizing amount of at least one excipient. For example, the excipient is selected from the group consisting of a buffer, a solubilizer, an isotonicity agent, an antioxidant, a chelating agent, an antibacterial agent, and a preservative. Those skilled in the art will understand that an excipient may have more than one function and may be classified into one or more defined groups.

[0089] In an embodiment, a parenteral composition comprising (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, and an excipient, wherein the excipient is present in a weight percent (w / v) of, for example, about 1.0%-10%, 10%-25%, 15%-35%, 0.5%-5%, 0.001%-1%, 0.01%-1%, 0.1%-1%, or 0.5%-1%, for example. In embodiments, the excipients are present in a weight percentage of, for example, about 0.001%-1%, 0.01%-1%, 1.0%-5%, 10%-15%, or 1%-15%.

[0090] In embodiments, parenteral compositions can be administered as needed, for example, once, twice, three or four or more times daily, or continuously as needed by the subject.

[0091] In an embodiment, a parenteral composition is provided that includes an active agent, such as, for example, (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, wherein the pH of the composition is about 4.0 to about 8.0. In an embodiment, the pH of the composition is, for example, about 5.0 to about 8.0, about 6.0 to about 8.0, or about 6.5 to about 8.0. In an embodiment, the pH of the composition is, for example, about 6.5 to about 7.5, about 7.0 to about 7.8, about 7.2 to about 7.8, or about 7.3 to about 7.6. In embodiments, the pH of the aqueous solution is, for example, about 6.8, about 7.0, about 7.2, about 7.4, about 7.6, about 7.7, about 7.8, about 8.0, about 8.2, about 8.4, or about 8.6.

[0092] In an embodiment, the present disclosure provides a method for treating PWS or a seizure disorder, comprising administering to a subject in need thereof a pharmaceutical composition comprising an active agent, for example, one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, in the respective amounts described herein, wherein the composition provides an in vivo plasma profile with a Cmax of less than about 800 ng / ml. In an embodiment, the composition provides improvement for 6 hours or more after administration to the subject.

[0093] In an embodiment, a pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, provides an in vivo plasma profile having a Cmax of, for example, less than about 2000 ng / ml, 1000 ng / ml, 850 ng / ml, 800 ng / ml, 750 ng / ml, 700 ng / ml, 650 ng / ml, 600 ng / ml, 550 ng / ml, 450 ng / ml, 400 ng / ml 350 ng / ml, or 300 ng / ml, wherein the composition provides an improvement in the subject's next day function. In embodiments, the pharmaceutical composition provides an in vivo plasma profile having a Cmax of, for example, less than about 250 ng / ml, 200 ng / ml, 150 ng / ml, or 100 ng / ml, where the composition provides an improvement in the subject's next day function. In embodiments, the pharmaceutical composition provides an improvement in one or more symptoms of the disorder for 6 hours or more after administration.

[0094] In an embodiment, the present disclosure provides a method for treating PWS or a seizure disorder, comprising administering to a subject in need thereof a pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, wherein the composition provides a consistent in vivo plasma profile having an AUC0-∞ of less than about 900 ng·hr / ml. In an embodiment, the pharmaceutical composition provides an improvement in the subject's next-day function. In an embodiment, the composition provides an in vivo plasma profile having, for example, an AUC0-∞ of less than about 850 ng·hr / ml, 800 ng·hr / ml, 750 ng·hr / ml, or 700 ng·hr / ml, wherein the pharmaceutical composition provides an improvement in the subject's next-day function. In an embodiment, the composition provides improvement in one or more symptoms of the disorder for 6 hours or more following administration.

[0095] In embodiments, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof a pharmaceutical composition comprising an active agent, e.g., one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, wherein the pharmaceutical composition provides an in vivo plasma profile having, e.g., an AUC0-∞ of less than about 650 ng·hr / ml, 600 ng·hr / ml, 550 ng·hr / ml, 500 ng·hr / ml, or 450 ng·hr / ml. In embodiments, the compositions provide an in vivo plasma profile having an AUC0-∞ of, for example, less than about 400 ng·hr / ml, 350 ng·hr / ml, 300 ng·hr / ml, 250 ng·hr / ml, or 200 ng·hr / ml. In embodiments, the pharmaceutical compositions provide an in vivo plasma profile having an AUC0-∞ of, for example, less than about 150 ng·hr / ml, 100 ng·hr / ml, 75 ng·hr / ml, or 50 ng·hr / ml. In embodiments, the compositions provide an improvement in the subject's next day function for, for example, 4 hours, 6 hours, 8 hours, 10 hours, or 12 hours or more following administration of the composition to the subject.

[0096] In an embodiment, the present disclosure provides a method for treating PWS or a seizure disorder, comprising administering to a subject in need thereof a first pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, and a second pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing.

[0097] In an embodiment, the second pharmaceutical composition provides an in vivo plasma profile with a mean AUC0-∞ that is about the same as the mean AUC0-∞ of the first pharmaceutical composition. In an embodiment, the second pharmaceutical composition provides an in vivo plasma profile with a mean AUC0-∞ that is at least about 20% less than the first pharmaceutical composition. In an embodiment, the present disclosure relates to a first pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutical acceptable salt of either of the foregoing, and a pharmaceutical composition comprising (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutical acceptable salt of either of the foregoing. The present invention provides a method for treating PWS or a seizure disorder, comprising administering to a subject in need thereof a second pharmaceutical composition comprising one or both of fluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutical acceptable salt of either of the foregoing, wherein the second pharmaceutical composition provides a stable in vivo plasma profile having a mean AUC0-∞ that is, for example, at least about 25%, 30%, 35%, 40%, 45%, or 50% less than the first pharmaceutical composition. In an embodiment, the composition provides an improvement in the subject's next day function. For example, the pharmaceutical composition can provide an improvement in one or more symptoms for, for example, about 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours or more after administration of the first and / or second pharmaceutical composition.

[0098] In embodiments, the present disclosure provides a method of treating PWS or a seizure disorder comprising administering to a subject in need thereof a first pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, and a second pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, wherein the second pharmaceutical composition provides an in vivo plasma profile having an AUC0-∞ of less than about 900 ng·hr / ml. In an embodiment, the second pharmaceutical composition provides an in vivo plasma profile having an AUC0-∞ of, for example, less than about 800 ng·hr / ml, 750 ng·hr / ml, 700 ng·hr / ml, 650 ng·hr / ml, or 600 ng·hr / ml. In an embodiment, the second pharmaceutical composition provides an in vivo plasma profile having an AUC0-∞ of, for example, less than about 550 ng·hr / ml, 500 ng·hr / ml, 450 ng·hr / ml, 400 ng·hr / ml, or 350 ng·hr / ml. In an embodiment, the second pharmaceutical composition provides an in vivo plasma profile having an AUC0-∞ of, for example, less than about 300 ng·hr / ml, 250 ng·hr / ml, 200 ng·hr / ml, 150 ng·hr / ml, or 100 ng·hr / ml. In an embodiment, a first and a second pharmaceutical composition are administered, and the composition provides an improvement in the subject's next day function. In an embodiment, the first pharmaceutical composition provides an improvement in one or more symptoms, for example, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours or more after administration of the first pharmaceutical composition.

[0099] In an embodiment, the present disclosure provides a method for treating PWS or a seizure disorder comprising administering to a subject in need thereof a first pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, and a second pharmaceutical composition comprising one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of any of the foregoing, wherein the first composition provides an in vivo plasma profile with a Cmax that is about 50% or greater than the Cmax provided by administration of the second pharmaceutical composition. As used herein, the Cmax provided by administration of the second pharmaceutical composition may or may not include the plasma profile contribution of the first pharmaceutical composition. In an embodiment, administration of the second pharmaceutical composition does not include the plasma profile contribution of the first pharmaceutical composition. In an embodiment, the first composition provides an in vivo plasma profile having a Cmax that is, for example, about 60%, 70%, 80%, or 90% or more greater than the Cmax provided by administration of the second pharmaceutical composition.

[0100] In an embodiment, the Tmax of the first pharmaceutical composition is less than 3 hours. In an embodiment, the Tmax of the first pharmaceutical composition is less than 2.5 hours. In an embodiment, the Tmax of the first pharmaceutical composition is less than 2 hours. In an embodiment, the Tmax of the first pharmaceutical composition is less than 1.5 hours. In an embodiment, the Tmax of the first pharmaceutical composition is less than 1 hour. In an embodiment, the Tmax of the first pharmaceutical composition is less than 0.5 hours. In an embodiment, the Tmax of the first pharmaceutical composition is less than 0.25 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 3 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 2.5 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 2 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 1.5 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 1 hour. In an embodiment, the Tmax of the second pharmaceutical composition is less than 0.5 hours. In an embodiment, the Tmax of the second pharmaceutical composition is less than 0.25 hours.

[0101] In an embodiment, the first pharmaceutical composition provides at least about 80% dissolution within the first 20 minutes of administration to a subject in need thereof. In an embodiment, the first pharmaceutical composition provides, for example, at least about 85%, 90% or 95% dissolution within the first 20 minutes of administration to a subject in need thereof. In an embodiment, the first pharmaceutical composition provides at least about 80% dissolution within the first 10 minutes of administration to a subject in need thereof.

[0102] In an embodiment, the administration of the first and second pharmaceutical compositions may be simultaneous or separated by a time interval to achieve long-term improvement in at least one symptom. In an embodiment, the first and second pharmaceutical compositions may be administered 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 hours apart. In an embodiment, the first and second pharmaceutical compositions may be administered, for example, within 15 minutes, 30 minutes, 1 hour, 2 hours, 12 hours, 18 hours, 24 hours, etc. In an embodiment, an improvement in at least one symptom of PWS or seizure disorder is provided for 8 hours or more after administration to a subject. In an embodiment, an improvement is provided for, for example, about 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 24 hours, 30 hours, 36 hours, 42 hours, or 48 hours after administration to a subject.

[0103] In an embodiment, the administration of the first and second pharmaceutical compositions can provide a synergistic effect that ameliorates at least one symptom of PWS or a seizure disorder.

[0104] In embodiments, provided herein are methods of treating PWS or seizures comprising administering to a subject in need thereof an initial drug dosage comprising a sub-therapeutic amount of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing. In an embodiment, treating PWS or a seizure disorder comprises administering to a subject in need thereof an initial drug dosage comprising a sub-therapeutic amount of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, wherein the composition provides improvement in one or more symptoms of the disorder for six hours or more following administration.

[0105] In an embodiment, the first and / or second pharmaceutical composition comprises a sub-therapeutic dose, which is an amount of an active agent, e.g., one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, that is less than the amount typically required for a therapeutic effect. In an embodiment, a sub-therapeutic dose is an amount of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, that does not alone provide an improvement in at least one symptom of PWS or a seizure disorder, but is sufficient to maintain such an improvement. In an embodiment, a method provides for administering a first pharmaceutical composition that provides an improvement in at least one symptom of PWS or a seizure disorder, and a second composition that maintains the improvement. In an embodiment, the second composition comprises a sub-therapeutic dose of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing. In an embodiment, following administration of the first pharmaceutical composition, the second pharmaceutical composition provides a synergistic effect of improving at least one symptom of PWS or a seizure disorder. In an embodiment, the second pharmaceutical composition provides a synergistic effect of improving at least one symptom of PWS or a seizure disorder.

[0106] In embodiments, the present disclosure provides a method of treating PWS or a seizure disorder, comprising administering to a subject in need thereof, for example, an initial drug dose of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, where the initial drug dose provides improvement for 6 hours or more after administration, and a second pharmaceutical composition comprising a sub-therapeutic dose of one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing.

[0107] In an embodiment, the first or second pharmaceutical composition is provided to the subject once in the evening and once in the morning.In an embodiment, the total amount of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or both, or a pharma- ceutically acceptable salt of either of the foregoing, administered to the subject in a 24-hour period is any of the respective amounts described herein.

[0108] In an embodiment, the first and / or second pharmaceutical composition may be provided with a conventional release profile or a modified release profile. The first and second pharmaceutical compositions may be provided simultaneously or separated by a time interval, e.g., 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 12 hours, etc. In an embodiment, the first and second pharmaceutical compositions may be provided with different drug release profiles creating a biphasic release profile. For example, the first pharmaceutical composition may be provided with an immediate release profile, e.g., ODDF, parenteral, etc., and the second pharmaceutical composition may provide an extended release profile. In an embodiment, one or both of the first and second pharmaceutical compositions may be provided with an extended or delayed release profile. Such compositions may be provided as pulsed release formulations, multi-layer tablets or capsules, including tablets, beads, granules, etc. In an embodiment, the first pharmaceutical composition is an immediate release composition. In an embodiment, the second pharmaceutical composition is an immediate release composition. In an embodiment, the first and second pharmaceutical compositions are provided as separate immediate release compositions, e.g., films, tablets or capsules. In an embodiment, the first and second pharmaceutical compositions are provided 12 hours apart.

[0109] It should be understood that the dosages of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or any of the pharma- ceutically acceptable salts provided herein, are applicable to all dosage forms described herein, including conventional dosage forms, modified dosage forms, the first and second pharmaceutical compositions, and parenteral formulations described herein. Those skilled in the art will determine the appropriate amount depending on criteria such as dosage form, route of administration, subject tolerance, efficacy, therapeutic goal and therapeutic benefit, among other pharma- ceutically acceptable criteria.

[0110] Combination therapy utilizing one or both of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, encompasses administration of the active agents together in the same mixture, or in separate mixtures. In an embodiment, the pharmaceutical composition can include two, three, or more active agents. In an embodiment, the combination provides more than additive effects in the treatment of a disease or disorder. Thus, the treatment for PWS or seizure disorder provided by the combination of combined agents provides synergistic effects and enhances efficacy.

[0111] In an embodiment, the combination therapy of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, is more effective at reducing the frequency or severity of a subject's symptoms than either of the compounds administered alone. In an embodiment, the combination therapy produces more than additive results compared to the compounds administered individually.

[0112] In an embodiment, subjects are started on a low dose and the dosage is increased. In this manner, it can be determined whether the subject is tolerating the drug well. Dosages can be lower for infants and children than for adults.

[0113] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0114] The term "about" or "approximately" as used herein means within an acceptable error range of a particular value as determined by one of ordinary skill in the art, which depends in part on the limitations of the method of measuring or determining the value, i.e., the measurement system. For example, "about" can mean within 3 or more than 3 standard deviations, according to the practice in the art. Alternatively, "about" can mean within a range of up to 20%, up to 10%, up to 5%, and / or up to 1% of the specified value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude of a value, preferably within 5-fold, more preferably within 2-fold.

[0115] "Improvement" is measured relative to at least one symptom of the aforementioned disorders: epilepsy, epilepsy with generalized tonic-clonic seizures, epilepsy with myoclonic absences, frontal lobe epilepsy, temporal lobe epilepsy, Landau-Kleffner syndrome, Rasmussen syndrome, Dravet syndrome, Dawes syndrome, CDKL5 disorder, infantile spasms (West syndrome), juvenile myoclonic epilepsy (JME), vaccine-associated encephalopathy, intractable childhood epilepsy (ICE), Lennox-Gast syndrome, This refers to the treatment of PWS or seizure disorders such as Leishman Syndrome (LGS), Retz Syndrome, Otahara Syndrome, childhood absence epilepsy, essential tremor, acute repetitive seizures, benign rolandic epilepsy, status epilepticus, refractory status epilepticus, super refractory status epilepticus (SRSE), PCDH19 pediatric epilepsy, abnormal EEG signs, drug withdrawal induced seizures, seizures due to alcohol withdrawal, increased seizure activity or spontaneous seizures (also called consecutive or cluster seizures).

[0116] By "improved next day function" or "improved next day function" is meant an improvement following awakening from a night's sleep in which the beneficial effect of administration of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid, or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115), or a pharma- ceutically acceptable salt of either of the foregoing, applied to at least one symptom of a syndrome or disorder described herein, is discernible subjectively by the subject or objectively by an observer for a period of time, e.g., 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 12 hours, 24 hours, etc., following awakening.

[0117] "PK" refers to the pharmacokinetic profile. Cmax is defined as the maximum plasma drug concentration (ng / ml) estimated during the experiment. Tmax is defined as the time (min) at which Cmax is estimated. AUC0-∞ is the total area under the plasma drug concentration-time curve from drug administration until drug elimination (ng·hr / ml or μg·hr / ml). The area under the curve is determined by clearance. Clearance is defined as the volume of blood or plasma where the drug content is completely cleared per unit time (ml / min).

[0118] "Treating", "treatment" or "treat" can refer to: alleviating or delaying the appearance of clinical symptoms of a disease or condition in a subject who may be afflicted with or predisposed to the disease or condition, but who has not yet experienced or exhibited clinical or subclinical symptoms of the disease or condition. In certain embodiments, "treating", "treat" or "treatment" can refer to preventing the appearance of clinical symptoms of a disease or condition in a subject who may be afflicted with or predisposed to the disease or condition, but who has not yet experienced or exhibited clinical or subclinical symptoms of the disease or condition. "Treating", "treat" or "treatment" can also refer to inhibiting a disease or condition, e.g., arresting or reducing the onset of or at least one clinical or subclinical symptom thereof. "Treating", "treat" or "treatment" can further refer to alleviating a disease or condition, e.g., causing regression of a disease or condition, or at least one clinical or subclinical symptom thereof. The benefit to the subject being treated is statistically significant, mathematically significant, or at least perceptible to the subject and / or physician. Nevertheless, prophylactic (preventative) and therapeutic (curative) treatments are two separate embodiments of the present disclosure.

[0119] "Pharmaceutically acceptable" refers to molecular entities and compositions that are "generally regarded as safe," e.g., physiologically tolerated and do not normally cause allergic or similar undesirable reactions, such as stomach upset, when administered to humans. In embodiments, the term refers to molecular entities and compositions that have been approved by a federal or state government regulatory agency as a GRAS listing under sections 204(s) and 409 of the Federal Food, Drug and Cosmetic Act, or a similar listing in the United States Pharmacopeia or another pharmacopoeia as generally recognized for use in animals, especially humans, that are subject to premarket review and approval by the FDA.

[0120] The previously mentioned "effective amount" or "therapeutically effective amount" can also mean a dosage sufficient to alleviate one or more symptoms of the syndrome, disorder, disease, or condition being treated, or otherwise provide the desired pharmacological and / or physiological effect. "Effective amount" or "therapeutically effective amount" may be used interchangeably herein.

[0121] "Co-administered with," "administered in conjunction with," "combination of," "in conjunction with," or "administered together" are used interchangeably and mean that two or more agents are administered during the course of treatment. The agents may be administered simultaneously or separately at intervals. The agents may be administered in a single dosage form or in separate dosage forms.

[0122] "Subjects in need thereof" include those with epilepsy, epilepsy with generalized tonic-clonic seizures, epilepsy with myoclonic absence, frontal lobe epilepsy, temporal lobe epilepsy, Landau-Kleffner syndrome, Rasmussen syndrome, Dravet syndrome, Dawes syndrome, CDKL5 disorder, infantile spasms (West syndrome), juvenile myoclonic epilepsy (JME), vaccine-associated encephalopathy, intractable childhood epilepsy (ICE), Lennox-Gastaut syndrome (LGS), Retz syndrome, The subjects may include individuals diagnosed with PWS or seizure disorders such as pediatric encephalopathy, Otahara syndrome, childhood absence epilepsy, essential tremor, acute repetitive seizures, benign rolandic epilepsy, status epilepticus, refractory status epilepticus, very refractory status epilepticus (SRSE), PCDH19 childhood epilepsy, abnormal EEG signs, drug withdrawal induced seizures, alcohol withdrawal seizures, increased seizure activity or spontaneous seizures (also called consecutive or cluster seizures). The method may be provided to any individual, for example, where the subject is a neonate, infant, pediatric subject (6 months to 12 years), adolescent subject (12 to 18 years), or adult (18 years or older). The subject may be a mammal. "Subject" and "patient" are used interchangeably herein.

[0123] A "prodrug" refers to a pharmacological agent (drug) that is administered to a subject in an inactive (or significantly less active) form. Once administered, the prodrug is metabolized in the body (in vivo) to a compound possessing the desired pharmacological activity.

[0124] "Analog" and "derivative" are used interchangeably to refer to a compound that has the same core as the parent compound, but may differ from the parent compound in the bond order, the absence or presence of one or more atoms and / or groups of atoms, and combinations thereof. A derivative may differ from the parent compound in one or more substituents present on the core, and may include one or more atoms, functional groups, or substructures. In general, derivatives can be envisioned, at least in theory, to be formed from the parent compound via chemical and / or physical processes.

[0125] The term "pharmaceutically acceptable salts" as used herein refers to derivatives of compounds defined herein, where the parent compound is modified by making its acid or base salt. Examples of pharmaceutically acceptable salts include, but are not limited to, inorganic or organic acid salts of basic residues such as amines; and alkali or organic salts of acidic residues such as carboxylic acids. Pharmaceutically acceptable salts include, for example, conventional non-toxic salts or quaternary ammonium salts of the parent compound formed from non-toxic inorganic or organic acids. Such conventional non-toxic salts include, but are not limited to, those derived from inorganic acids, such as hydrochloric acid, hydrobromic acid, sulfuric acid, sulfamic acid, phosphoric acid, nitric acid, and the like; and those prepared from organic acids, such as acetic acid, propionic acid, succinic acid, glycolic acid, stearic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, pamoic acid, maleic acid, hydroxymaleic acid, phenylacetic acid, glutamic acid, benzoic acid, salicylic acid, sulfanilic acid, 2-acetoxybenzoic acid, fumaric acid, tolunesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid, ethanedisulfonic acid, oxalic acid, and isethionic acid. Pharmaceutically acceptable salts can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. EXAMPLES

[0126] The examples provided herein are included merely to supplement the disclosure herein and should not be construed as limiting in any way.

[0127] Example 1 Prospective evaluation of the safety and efficacy of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid for ghrelin suppression in individuals with Prader-Willi syndrome The purpose of this study is to evaluate the effect of (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid on ghrelin levels, hunger, and body weight in people with Prader-Willi syndrome. The study is a multicenter, randomized, placebo-controlled, double-blind study in which subjects who meet the inclusion criteria will be randomly assigned to receive placebo or active drug. Enrolled subjects will have a confirmed diagnosis of PWS by chromosome analysis (i.e., paternally derived in situ deletion of chromosome 15Q, uniparental maternal disomy, or other chromosome 15 abnormality), be aged 18 years or older, and have free T4 and TSH levels in the normal range (with or without thyroxine replacement). Subjects with confirmed hypogonadism that can be corrected with an adequate dose of sex steroid replacement will be treated for at least 6 months prior to inclusion, with no change in dose during the study.

[0128] After baseline testing, subjects will receive either (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid or a placebo for six months. At the end of this initial six-month treatment period and four-month washout period, study subjects will rotate to receive the alternative treatment (placebo or (1S,3S)-3-amino-4-(difluoromethylidene)cyclopentane-1-carboxylic acid) for another six months. Subjects will be followed for a total of 16 months at scheduled visits: 0, 2, 6, 10, 12, and 16 months. During each of these visits, the study will measure the ability to process glucose (sugar), the amount of energy burned as heat, the amount of body fat, levels of the hormone ghrelin, and the amount of food eaten in meals. During these studies, participants will return monthly for physical exams and blood draws to check liver enzymes. Primary outcome measures are ghrelin levels (change from baseline to 6 months), appetite (change from baseline to 6 months), and weight (change from baseline to 6 months). Secondary outcome measures are hormone levels (change from baseline to 6 months), body composition (change from baseline to 6 months), energy expenditure (change from baseline to 6 months), and glucose metabolism (change from baseline to 6 months).

[0129] Example 2 A prospective evaluation of the safety and efficacy of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid on weight gain and body composition in adults with Prader-Willi syndrome The purpose of this study is to evaluate the effect of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115) on appetite, body weight, body fat and growth hormone levels in subjects with PWS. This is a double-blind, placebo-controlled clinical trial of PWS in a total of 18 young adults with PWS, aged 18-35 years. Subjects will be selected if they have previously confirmed Prader-Willi syndrome by standard genetic testing (DNA methylation testing) or meet the following clinical diagnostic criteria: the presence of at least four of the six cardinal features of the PWS syndrome, including 1) childhood hypotonia, 2) abnormal pubertal development, 3) obesity after early infancy, 4) impaired central nervous system function, 5) facial dysmorphism, and 6) short stature. In addition, subjects must have one or more of the following features commonly associated with PWS: 1) small hands and feet, 2) skin problems, 3) food-related behavioral problems, and 4) reduced pain sensitivity. Subjects must have a BMI of at least 30 or greater. Subjects will be divided into two groups, control and intervention, and will be treated with either placebo (an inactive drug), or (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (KT-II-115) for a total of 6 months. Body weight, fat distribution, objective and subjective assessments of hunger, fasting blood samples for measurement of ghrelin and leptin, serum lipids, IGF-1 (growth hormone-related protein), insulin and glucose concentrations will be measured at enrollment, 3 months, and at the end of the study. The percentage of body fat to muscle will be determined using a radiological technique, a whole-body dual-energy x-ray absorptiometry (DEXA) scan, and also by measurements of skinfold thickness, waist and hip circumference at enrollment and at the end of the study, before the intervention.

[0130] Example 3 (S)-3-amino-4-(difluoromethyl)-2-(tri ... Prospective evaluation of the efficacy of KT-II-115 (renyl)cyclopent-1-ene-1-carboxylic acid therapy The purpose of this trial is to study the effects of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid therapy on food intake, hunger, weight, body composition, calorie burning efficiency, biomarkers of weight regulation, and growth hormone markers over 6 months in children and young adults with PWS.This is a double-blind, placebo-controlled clinical trial in subjects with a diagnosis of PWS confirmed by chromosome analysis, age 5-21 years, BMI for age ≥85th percentile, and free T4 and thyroid-stimulating hormone (TSH) levels (either endogenous or with thyroxine replacement) within the normal range.

[0131] The primary outcome measures were the number of participants showing a decrease in fasting total ghrelin from baseline at 6 months of treatment with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo, the number of participants who lost weight from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy, and the number of participants who lost BMI from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy. The primary outcome measures are the number of participants with a decrease in z-score, the number of participants with a decrease in skinfold measures from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy, and the number of participants with a decrease from baseline in hunger and food intake as measured by hunger and binge eating by questionnaire and parent-reported 72-hour food recall at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy. Multiple questionnaires consisting of a series of free text response questions and a food diary are combined to provide a behavioral assessment of the participants' food status regarding hunger and food intake. There is no defined scale for this assessment. Each participant's responses and parent's responses are combined. An additional primary outcome measure is the number of participants with improved insulin regulation from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy. Insulin regulation will be measured by immunochemiluminescence assay, number of participants with improved adiponectin regulation from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy, number of participants with improved leptin regulation from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy, number of participants with improved peptide YY (PYY) regulation from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy.Secondary outcome measures were the number of participants with reduced body composition from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy as measured by air displacement plethysmography (BOD POD® Body Composition Tracking System) at 0, 3, and 6 months, the number of participants with reduced body composition from baseline at 6 months of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo therapy as measured by dual energy x-ray absorptiometry (DEXA) scan, and resting energy expenditure measured by indirect calorimetry at 0, 3, and 6 months.

[0132] Example 4 Prospective evaluation of the efficacy of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid in pediatric subjects with status epilepticus This study aims to determine whether (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid provides improvement in one or more symptoms of status epilepticus. Epilepsy is one of the most common severe neurological disorders in childhood. Medications with novel mechanisms of action are needed to attempt to address the unmet clinical need for seizure control in subjects with status epilepticus. Additionally, the aim of this study is to evaluate the safety and tolerability of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid as a treatment for subjects with status epilepticus.

[0133] (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof, such as the hydrochloride salt, is administered intravenously to pediatric subjects (3 months to 16 years) in amounts ranging from 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9, and 10 mg as a 50 mL intravenous short-term infusion solution (infusion rate 200 mL / hour) within 15 minutes. Subjects whose seizures do not cease or recur within 10 minutes of the first dose can receive an injection of the same amount of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid 10 minutes after the first dose. Subjects whose seizures stop within 10 minutes of the first dose, but recur subsequently (within 12 hours), can receive an injection of the same dose of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid; a total of two doses are allowed in the study.

[0134] Inclusion criteria: Subjects with status epilepticus or recurrent status epilepticus / cluster seizures, with seizures assessable by the investigator's visual observation based on motor symptoms or with seizures assessable by EEG. Subjects with generalized seizures, partial seizures, or status epilepticus with secondarily generalized seizures lasting 5 minutes or more. Subjects with recurrent status epilepticus / cluster seizures with 3 or more consecutive episodes of generalized-onset, partial-onset, or secondarily generalized seizures within 1 hour. Subjects not younger than 3 months (either gender can participate in the study).

[0135] Primary outcome measures: Percentage of participants with clinical benefit [Time frame: 30 minutes] The percentage of participants whose first seizure stopped within 10 minutes of the first dose and who remained seizure-free for at least 30 minutes after completion of the first dose (responder rate)

[0136] Secondary outcome measures: Percentage of participants whose first seizure stopped within 10 minutes and remained seizure-free for at least 30 minutes after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (either the first dose or the second dose [10-30 minutes after the first dose]). [Time frame: 1 hour] Percentage of participants whose seizures stopped within 10 minutes after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (first dose only) and remained seizure-free for at least 12 hours after administration. [Time frame: 12 hours] Percentage of participants whose first seizure stopped within 10 minutes after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (either the first dose or the second dose [10-30 minutes after the first dose]) and who remained seizure-free for at least 12 hours. [Time frame: 12 hours] Percentage of participants whose seizures stopped within 10 minutes after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (first dose only) and who remained seizure-free for at least 24 hours after administration. [Time frame: 24 hours] Percentage of participants whose first seizure stopped within 10 minutes after administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (either the first dose or the second dose [10-30 minutes after the first dose]) and who remained seizure-free for at least 24 hours. [Time frame: 24 hours] Time from administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (first dose only) to resolution of seizure. [Time frame: 24 hours] · Time from administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (either the first or second dose) to resolution of seizure. [Time frame: 24 hours] Time from resolution to recurrence of seizures following administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (first dose only, within 24 hours). [Time frame: 24 hours] Time from resolution to recurrence of seizures following administration of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (either the first or second dose, within 24 hours). [Time frame: 24 hours]

[0137] Example 5 Prospective evaluation of the use of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid to prevent conversion in infants with tuberous sclerosis complex A multicenter, randomized, placebo-controlled, double-blind clinical trial. Eighty infants with tuberous sclerosis complex who are less than 6 months of age before the onset of their first seizure will be enrolled. Early identification of electroencephalography (EEG) biomarkers and early versus delayed treatment with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid in infants with tuberous sclerosis complex (TSC) will be evaluated for positive impact on developmental outcomes at 24 months of age. Early treatment should prevent or reduce the risk of developing infantile spasms and refractory seizures. This preventative approach should result in more favorable long-term cognitive, behavioral, developmental and psychiatric outcomes and significantly improve overall quality of life.

[0138] Inclusion criteria were infants aged 6 months or younger, no history of seizures or infantile spasms, or evidence of subclinical electrographic seizures on prior video-EEG, and fulfilling genetic or clinical diagnostic criteria for TSC, the latter based on current recommendations for diagnostic evaluation including physical examination, neuroimaging, and echocardiography.

[0139] (S)-3-Amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or control is administered based on body weight at 1 mg to 50 mg / kg / day in two divided doses per established recommended guidelines (1 mg / kg / day, increased by 10 mg / kg / day every 3 days as needed to a maximum dose of 50 mg / kg / day, administered in two divided doses per day).

[0140] Subjects randomized to (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid in Arm A will be treated with up to 50 mg / kg / day of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or placebo until 24 months of age or until they show evidence of clinical seizures or electrographic seizures on video-EEG. If electrographic or clinical seizures occur during study drug administration, subjects will transition to the open-label phase of the study (Arm B) and treatment will continue until 36 months of age. Open-label (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid (treatment group B) will be administered based on body weight at 1 mg to 50 mg / kg / day in two divided doses per established recommended guidelines (1 mg / kg / day, increased by 10 mg / kg / day every 3 days as needed to a maximum dose of 50 mg / kg / day, administered in two divided doses per day).

[0141] Primary outcome measures: Bayley Scales of Infant and Toddler Development at 24 months and Bayley Scales of Infant and Toddler Development cognitive assessment scores at 24 months will be used in data analysis to compare the developmental effects of early versus delayed treatment with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid.

[0142] Secondary outcome measures: 1. To evaluate the number of subjects who develop seizures when treated with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid as seizure prophylaxis;2. The time to first clinical seizure in subjects will be measured for both placebo and (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid subjects;3. Prevalence of drug-resistant epilepsy;4. Evaluate Vineland II scores at 12, 24, and 36 months and the impact of early versus delayed treatment with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid;5. Evaluate ADOS2 scores at 24 and 36 months and the impact of early versus delayed treatment;6. Number of subjects with (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid-related adverse events, serious adverse events assessed by CTCAE v4.0, and the Risk Evaluation and Mitigation Strategies (REMS) scale.

[0143] It should be understood that the examples and embodiments provided herein are exemplary examples and embodiments. Those skilled in the art will envision various modifications of the examples and embodiments consistent with the scope of the disclosure of this specification. Such modifications are intended to be included in the scope of the claims.

Claims

1. A pharmaceutical composition for treating a CDKL5 disorder in a subject, comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutical acceptable salt thereof, A pharmaceutical composition, wherein an amount of 0.01 mg to 75 mg of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to a subject.

2. 2. The pharmaceutical composition of claim 1, wherein a total amount of 1 mg to 50 mg of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to the subject in a 24 hour period.

3. The pharmaceutical composition of claim 1, wherein at least one symptom selected from the group consisting of ataxia, gait disturbance, speech disorder, speech, cognitive impairment, dyskinesia, clinical seizures, subclinical seizures, hypotonia, hypertonia, salivation, mouthing behavior, aura, convulsions, repetitive movements, abnormal sensations, simple focal seizures, complex focal seizures, generalized seizures, absence seizures, tonic seizures, atonic seizures, myoclonic seizures, tonic-clonic seizures, clonic seizures, seizure frequency, and seizure severity is improved.

4. 2. The pharmaceutical composition of claim 1, wherein the subject has been diagnosed with a CDKL5 disorder and at least one symptom selected from the group consisting of seizures, scoliosis, visual impairment, sensory problems, gastrointestinal problems, low or poor muscle tone, hand wringing behavior, hand mouthing, significant developmental delay, limited or absent speech, absent or poor eye contact, gastroesophageal reflux, constipation, small and cold feet, irregular breathing, teeth grinding, episodes of laughing or crying for no reason, very limited manual skills, autistic-like tendencies, cortical visual impairment, apraxia, eating and drinking challenges, sleep disorders, sideways glances, and cross-legged habit is improved.

5. A pharmaceutical composition for treating a CDKL5 disorder in a subject, comprising (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutical acceptable salt thereof, A pharmaceutical composition administered to a subject following detection of an abnormal EEG and prior to the onset of a clinical seizure to reduce or prevent symptoms of a CDKL5 disorder.

6. 6. The pharmaceutical composition of claim 5, wherein a total amount of 1 mg to 50 mg of (S)-3-amino-4-(difluoromethylenyl)cyclopent-1-ene-1-carboxylic acid or a pharma- ceutically acceptable salt thereof is administered to the subject in a 24 hour period.

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