WO2009151741A1 - Methods and compositions for the intracerebroventricular administration of felbamate - Google Patents

Abstract

The present invention concerns methods, compositions, and apparatus for the ICV administration of felbamate. In particular embodiments, ICV administration is advantageous for decreasing the systemic concentrations of felbamate, thereby decreasing side-effect toxicity, while allowing more effective delivery of felbamate to the site of action, simultaneously decreasing the dosage delivered to the individual. In particular embodiments, ICV delivery may be of use for individuals who have previously proven to be refractory to systemic administration of anti-epilepsy agents, in some cases due to systemic side-effects, or for those individuals whose symptoms are of sufficient severity to warrant more aggressive therapeutic intervention. ICV administration allows not only lower systemic concentration but also higher therapeutically effective concentration within the CNS.

Description

METHODS AND COMPOSITIONS FOR THE INTRACEREBROVENTRICULAR ADMINISTRATION OF FELBAMATE

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority benefit of U.S. provisional application serial no. 61/041,493, filed April 1, 2008, which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Epilepsy affects approximately 50 million people worldwide. Within the U.S. and European Union, the prevalence of epilepsy is reported to be 5 - 10 cases per 1,000 with an incidence of approximately 50 new cases per 100,000. The World Health Organization reports nearly double these numbers in developing countries. Despite the introduction of new medications and increased use of polypharmacy, 30% of epilepsy patients continue to suffer from uncontrolled seizures. More than 24% of total patients experience more than one seizure per month.

[0003] Seizure types are organized according to whether the source of the seizure within the brain is localized (partial or focal onset seizures) or distributed (generalized seizures). Partial seizures are further divided based on the extent to which consciousness is affected. If it is unaffected, then it is a simple partial seizure; otherwise, it is a complex partial (psychomotor) seizure. A partial seizure may spread within the brain - a process known as secondary generalization. Generalized seizures are divided according to the effect on the body, but all involve loss of consciousness. These include absence (petit mal), myoclonic, clonic, tonic, tonic-clonic (grand mal), and atonic seizures.

[0004] People with refractory epilepsy have not achieved adequate control of their seizures from two first line medications. Medical refractory epilepsy represents a special population of patients with significantly higher mortality, morbidity, economic costs, and diminished quality of life compared with non-refractory patients. Current options for these patients include surgical resections and vagal nerve stimulator implantation (VNS). It is widely accepted that while VNS offers a modest benefit it does not usually offer a dramatic improvement in patient quality of life or attenuation of seizures and is associated with significant financial costs. [0005] Successful treatment with anticonvulsants is dependent on achievement of consistent steady state levels of effective medication within the brain. Failure to achieve adequate drug dosing regimens leads to an increase in seizure frequency. Non-compliance is a major cause of increased health care costs, driven by increased hospitalization as compared to the compliant patient. On average, between 30-40% of epileptic patients appear to be non- compliant with their drug regimen. Some refractory epilepsy patients are candidates for removing part of the brain through neurosurgical procedures that are expensive and risky. Evaluation and selection of patients for surgery requires a significant investment of time and expense to identify the appropriate candidates. It is estimated that while approximately 10% of patients referred for neurosurgical evaluation may benefit from surgery less than 1% actually receives the surgical procedure. Issues impacting this include cost, availability of surgeons to perform these complicated procedures, and patient concerns related to removing parts of the brain.

[0006] Felbamate (2-phenyl- 1,3 -propanediol dicarbamate, marketed under the brand name Felbatol by MedPointe) is an anticonvulsant drug used in the treatment of epilepsy. It is used to treat, e.g., partial seizures (with and without generalization) in adults and partial and generalized seizures associated with Lennox-Gastaut syndrome in children.

[0007] In humans, the most common adverse events associated with oral felbamate administration as monotherapy are anorexia, vomiting, insomnia, nausea, and headache (Felbatol Prescribing Information). However, post-marketing reports of serious and potentially life-threatening adverse effects have limited the use of felbamate. There have been 34 reported cases of aplastic anemia and 18 cases of liver failure reports to date. The increased risk of potentially fatal aplastic anemia and/or liver failure limit the usage of felbamate to severe refractory epilepsy. As described by current practice guidelines of the American Academy of Neurology, given the risk/benefit ratio, felbamate should be considered and used with close clinical monitoring in patients with seizures that have been uncontrolled by other anti-epilepsy agents.

[0008] There remains a significant interest in and need for additional or alternative therapies for treating epilepsy, especially refractory epilepsy. Treatment options that result in greater patient compliance and/or fewer adverse side-effects are desired. BRIEF SUMMARY OF THE INVENTION

[0009] The present invention provides methods, formulations, apparatuses containing one or more compositions, and kits containing compositions for intracerebroventricular (ICV) administration of felbamate for a condition for which treatment with felbamate is beneficial, such as epilepsy.

[0010] In one aspect, the invention provides methods for treating epilepsy in an individual (such as a human) in need thereof. In some embodiments, the method involves administering to the human a pharmaceutical composition comprising (i) between about 1 mg to about 250 mg of felbamate and (ii) a cyclodextrin, a polyethylene glycol (PEG), or dimethylsulfoxide (DMSO). In some embodiments, the total daily dose of felbamate for the human is between about 1 mg to about 250 mg of felbamate, such as between about 1 mg to about 180 mg, and between about 10 mg to about 40 mg of felbamate. In some embodiments, the amount of felbamate administered is below the level that produces a clinically unacceptable level of toxicity (such as toxicity measured in rats, dogs, or humans using any of the methods described herein).

[0011] In some embodiments, the pharmaceutical composition is administered using an ICV route of administration. In certain embodiments, felbamate is administered to the third and/or fourth cerebral ventricle. In certain embodiments, felbamate is administered to one or both lateral cerebral ventricles. In some embodiments, the method also includes administering felbamate by a second route of administration other than ICV administration. In some embodiments, the second route of administration involves administration of felbamate to the lumbar cistern and/or cisterna magna. In some embodiments, felbamate is administered by an ICV route of administration and a second route of administration sequentially. In some embodiments, felbamate is administered by an ICV route of administration and a second route of administration simultaneously. In some embodiments, ICV delivery results in a lower concentration of felbamate in one or more peripheral tissues when compared to systemic drug delivery.

[0012] In some embodiments, the pharmaceutical composition is administered over at least about 1, 2, 3, 4, 5, 6, or more months via an implantable delivery device. In some embodiments, the human is selected from a population of humans who are refractory to treatment via systemic administration of felbamate. In some embodiments, the human is selected from a population of humans who are refractory to treatment via systemic administration of one or more compounds for the treatment of epilepsy other than felbamate. In some embodiments, the refractory human shows an alleviation or prevention of one or more symptoms when treated by ICV administration of the pharmaceutical composition.

[0013] In some embodiments, the cyclodextrin is β-hydroxypropyl-cyclodextrin. In some embodiments, the pharmaceutical composition contains between about 1 to about 35% cyclodextrin (w/w). In some embodiments, the pharmaceutical composition comprises felbamate and PEG. In some embodiments, the PEG is PEG 300, PEG 400, or PEG 600. In some embodiments, the concentration of felbamate in PEG is between about 1 mg/ml to about 150 mg/ml (such as between about 100 mg/ml to about 150 mg/ml). In some embodiments, the pharmaceutical composition comprises felbamate and DMSO. In some embodiments, the concentration of felbamate in DMSO is between about 1 mg/ml to about 450 mg/ml (such as between about 350 mg/ml to about 450 mg/ml).

[0014] In some embodiments, felbamate maintains solubility in the pharmaceutical composition for at least about 1, 2, 3, 4, 5, 6, or more months at physiological temperature and pH. In some embodiments, the felbamate maintains solubility in cerebral spinal fluid upon ICV administration to the human.

[0015] In some embodiments, the method includes administering a second therapy comprising another compound for the treatment of epilepsy. In some embodiments, the second therapy is an anti-epilepsy agent that acts on the GABA system, a sodium channel, and/or a calcium channel. In some embodiments, the second therapy is selected from the group consisting of lamictal, bumex, tegretol, valproate, adenosine, pharmaceutically acceptable salts, esters, and acids thereof, and combinations thereof. In some embodiments, the second therapy is administered using an ICV route of administration. In certain embodiments, the second therapy is administered to the third and/or fourth cerebral ventricle. In certain embodiments, the second therapy is administered to one or both lateral cerebral ventricles. In some embodiments, the second therapy is administered to the lumbar cistern and/or cisterna magna. In some embodiments, felbamate and the second therapy are contained in the same pharmaceutical composition. In some embodiments, felbamate and the second therapy are contained in the separate pharmaceutical compositions. In some embodiments, felbamate and the second therapy are administered sequentially. In some embodiments, felbamate and the second therapy are administered simultaneously. [0016] In another aspect, the invention features pharmaceutical compositions that comprise (i) between about 1 mg to about 250 mg of felbamate (such as about 1 mg to about 180 mg) and (ii) a cyclodextrin, a PEG, or DMSO. Compositions may be designed that are soluble and stabilized for long-term storage, for example in a fluid reservoir of a delivery apparatus. These compositions may be provided in kits containing the composition in solution or in dry form in an appropriate receptacle. The kit may also contain a pharmaceutically acceptable excipient and instructions for use. The kit may also contain an appropriate delivery apparatus for delivering the composition to the individual to be treated, or an appropriate device for delivering the composition to a fluid reservoir of a pump system. An appropriate receptacle for the composition may be a fluid reservoir that can be used as part of a delivery apparatus.

[0017] In accordance with certain aspects of the invention, a delivery apparatus may comprise one or more of the following: a pump, fluid reservoir, monitoring system, a programmable control system, an ICV catheter, a battery, and/or other elements known in the art.

[0018] In yet other aspects of the invention, methods for ICV administration of felbamate are provided. Such methods may comprise administering a stabilized composition via an ICV route of administration to an individual (such as a human) in need thereof. In certain embodiments, the methods may comprise obtaining a stabilized composition of felbamate, storing the stabilized composition in a delivery apparatus (for example an ICV delivery apparatus), and delivering via an ICV route of administration measured amounts of felbamate at predetermined time intervals. In certain embodiments, ICV administration may be particularly efficacious in individuals who have been found to be refractory to standard systemic administration of felbamate or other anti-epilepsy agents. In more particular embodiments, individuals who have failed two or more standard systemic therapies or whose conditions are severe enough to warrant more aggressive treatment than standard systemic therapies may benefit from ICV delivery.

[0019] In one aspect, the invention features an ICV formation of felbamate for use as a medicament. In some embodiments, the medicament is used to treat any condition for which treatment with felbamate is beneficial, such as epilepsy. In some embodiments, the ICV formulation comprises any of the pharmaceutical compositions described herein. [0020] In some embodiments, the invention features the use of an ICV formation of felbamate for the manufacture of a medicament. In some embodiments, the medicament is used to treat any condition for which treatment with felbamate is beneficial, such as epilepsy. In some embodiments, the ICV formulation comprises any of the pharmaceutical compositions described herein.

[0021] These and other aspects of the invention will become apparent to one of skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a positive atmospheric pressure chemical ionization (APCI) product ion mass spectrum (m/z = 256.2 => 50 - 265 (-10.0V)) obtained from a 5 μL loop injection of 10.2 μg/mL of felbamate standard solution.

[0023] Figure 2 is a positive APCI selected reaction monitoring (m/z = 256.2 => 177.8 (- 10.0V)) mass chromatogram obtained from a 0.510 ng/mL (LLOQ) standard sample of felbamate prepared in control canine brain. The peak eluting at 3.61 minutes corresponds to felbamate.

[0024] Figure 3 is a calibration curve of felbamate in canine brain.

[0025] Figure 4 is a positive APCI selected reaction monitoring (m/z = 256.2 => 177.8 (- 10.0V)) mass chromatogram obtained from a 5.00 ng/mL quality control sample of felbamate prepared in control canine brain.

[0026] Figure 5 is a positive APCI selected reaction monitoring (m/z = 256.2 => 177.8 (- 10.0V)) mass chromatogram obtained from a 50.0 ng/mL quality control sample of felbamate prepared in control canine brain.

[0027] Figure 6 is a positive APCI selected reaction monitoring (m/z = 256.2 => 177.8 (- 10.0V)) mass chromatogram obtained from a 200 ng/mL quality control sample of felbamate prepared in control canine brain.

[0028] Figure 7 is a calibration curve A of felbamate in canine plasma.

[0029] Figure 8 is a calibration B curve of felbamate in canine plasma. [0030] Figure 9 is a calibration C curve of felbamate in canine plasma.

[0031] Figure 1OA is a graph showing the stability of a felbamate and hydroxypropyl-β- cyclodextrin formulation at 37 °C up to 12 months.

[0032] Figure 1OB is a table showing the assay accuracy and precision for measuring felbamate levels.

[0033] Figure 11 is a graph showing that ICV administration of felbamate delayed the onset of seizures in a rat animal model.

[0034] Figure 12A is a table showing the CSF and plasma levels of felbamate in a single beagle dog during ICV felbamate administration.

[0035] Figure 12B is a graph of the CSF and plasma levels of felbamate in a single beagle dog during ICV felbamate administration.

[0036] Figures 13A-13H are graphs of the effect of felbamate on rats in open field and elevated plus maze assays.

[0037] Figure 14 is a graph of the effect of felbamate on rats in the Porsolt FST assay.

[0038] Figure 15 is a table summarizing the effect of felbamate on sedation and ataxia in rats.

[0039] Figures 16A and 16B are graphs of the effect of felbamate and vehicle controls on weight gain in rats.

[0040] Figure 17 is a table summarizing the effect of felbamate on blood analysis in rats.

[0041] Figures 18A- 18C are a table showing the concentration of felbamate in the brain of rats after ICV administration of felbamate.

[0042] Figures 19A and 19B are a table showing the concentration of felbamate in the CSF of rats after ICV administration of felbamate.

[0043] Figures 2OA and 2OB are a table showing the concentration of felbamate in the plasma of rats after ICV administration of felbamate. [0044] Figure 21 is a table showing the concentration of felbamate in the bone marrow of rats after ICV administration of felbamate.

[0045] Figures 22A and 22B are a table showing the concentration of felbamate in the heart of rats after ICV administration of felbamate.

[0046] Figures 23 A and 23B are a table showing the concentration of felbamate in the kidney of rats after ICV administration of felbamate.

[0047] Figures 24A and 24B are a table showing the concentration of felbamate in the liver of rats after ICV administration of felbamate.

DETAILED DESCRIPTION OF THE INVENTION

[0048] In certain aspects, the present invention relates to methods, pharmaceutical compositions, apparatuses containing one or more compositions, and kits containing compositions for intracerebroventricular (ICV) administration of felbamate for the treatment of epilepsy, such as refractory epilepsy. In some embodiments, felbamate is used for the treatment of severe partial onset seizures with or without secondary generalization in patients who have failed adequate oral drug treatment regimens. Included in this subset of epilepsy patients are patients with debilitating disease and patients who have failed treatment with at least two effective medications given at adequate doses. ICV administration allows much lower doses to be used than required for oral administration of felbamate. These lower doses may reduce or prevent adverse side-effects from felbamate.

[0049] ICV administration (compared to oral administration) may have superior efficacy, substantially decreased systemic exposure of felbamate, improved patient compliance, and decreased drug-drug interactions due to decreased drug effects on hepatic drug metabolism. The animal studies described herein strongly suggest that ICV administration can effectively deliver therapeutic levels of felbamate to the brain with relatively low systemic exposure.

[0050] As an example of this approach, partial onset seizures are generated by abnormal discharges from cortical neurons that are in close proximity to the ventricular surface. These neurons are very accessible to CSF based drag delivery. In addition to potential efficacy benefits, resulting from the provision of sustained/constant exposure to selected areas of the brain, potential benefits from ICV administration also include: 1) a reduction in systemic exposure and systemic side-effects; 2) improved compliance and dosing, as the infusion pump is filled, e.g., every three months by a physician who provides the capacity to improve patient adherence and can program delivery to adjust to clinical results; and 3) improved overall therapeutic response (such as improved response due to sustained exposure of epileptogenic foci within the brain to near constant therapeutic levels of felbamate. Medication administered via an ICV delivery device has less varied drug levels than a similar drug administered orally and intermittently, while computerized delivery offers the potential for programmed titration and tapering. Lastly, this procedure is much less expensive than traditional epilepsy surgery.

[0051] In accordance with some embodiments of the present invention, it has been found desirable to formulate compositions of felbamate for ICV administration at relatively high concentrations so that small injection volumes are sufficient to attain therapeutic drug levels within the brain. These small dosages result in marked advantages in therapeutic outcome in terms of toxicity, side-effects, dosing regimens, patient compliance, etc.

[0052] As described further below, rat and dog animal models have been used to assess the efficacy, distribution, pharmacokinetics, and toxicology of felbamate when administered ICV. For example, the ICV efficacy of felbamate has been established in acute (single-dose) rat studies. A dose of 17 mM of felbamate in 5 uL in rats was the lowest effective dose effective in acutely diminishing the PTZ threshold in a rat model of acute status epilepticus. Dosing of a concentration 4.5 fold higher for 28 days in rats demonstrated no evidence of overt toxicity or neurobehavioral effects (activation, sedation, weight gain, ataxia, depression, or anxiety). In particular, a 28-day toxicology study was performed in rats. A formulation of felbamate and cyclodextrin was delivered via implantable pumps into the lateral ventricle at doses 1/2 log and 1 log higher on a total dose basis than the anticipated efficacious dose based on single-dose rat efficacy experiments. In this study, felbamate produced no clinical observations or alterations in behavior (including no evidence of anxiety, ataxia, or sedation), did not alter body weight, and was not associated with any neuropathology or systemic tissue pathology.

[0053] Studies in dogs provide information on the doses and rate of infusion required to achieve anticipated therapeutic tissue concentrations in wide areas of cortex. In an on-going study pharmacokinetic and tolerability study in beagle dogs, results indicated that 0.2 mg/ml administered ICV continuously over 24 hours each day for 8 days at a rate of 50 uL per hour for a total daily dose of 0.24 mg was associated with low plasma felbamate concentrations of approximately 10 ng/mL after steady state is achieved. A higher total daily dose level of 0.72 mg also produced low plasma felbamate concentrations of approximately 16 ng/mL. Corresponding CSF levels ranged from 4 - 17 fold higher than plasma levels. The low and high dosing levels in this study were more than 15000- and 5000-fold lower, respectively, than therapeutic doses in humans (3600 mg/day). Therapeutic doses in human generally produce average plasma concentrations of approximately 50 ug/mL. Similarly, the low and high dosing levels in this study were approximately 3800 - 1300 fold lower than oral doses in dogs that are associated with a 50 ug/mL plasma concentration range (100 mg/kg) (McGee et al, 1998). No overt signs of toxicity were noted in this study. If desired, additional canine dosing studies ca be performed to test higher ICV felbamate doses, as well as analyze the regional distribution of felbamate.

[0054] Based upon these results, at least a 30-fold lower dose of ICV felbamate on an mg/kg basis compared to that associated with oral dosing in humans is necessary to achieve therapeutic activity. This dose provides much lower serum levels of medication than oral administration of felbamate. It is anticipated that human dosing can be accomplished at an administered concentration of less than 12 mg/mL with a dose volume of about 250 uL to about 450 uL a day. At this concentration, the pump is refilled approximately every 3 months assuming a 40 cc pump.

Pharmaceutical Compositions

[0055] One aspect of the invention is drawn to pharmaceutical compositions of felbamate suitable for ICV administration, particularly long term or chronic ICV administration, e.g., using implantable pumps. In various embodiments, the pharmaceutical composition includes felbamate and a cyclodextrin.

[0056] In certain aspects, the pharmaceutical compositions of the present invention allow for formulation of felbamate at higher dosage concentrations than typically used for systemic administration. As described in further detail below, the compositions of the present invention, in certain embodiments, provide for maximal solubility and stability under conditions of use during ICV administration, particularly chronic ICV administration. In this regard, it has been found in accordance with certain embodiments of the invention that the compositions, when administered via ICV administration routes, are suitable for use at higher dosage concentrations without increased risks of toxicity, as compared to systemic administration routes. In other embodiments, it has been found that significantly smaller amounts of the compositions of the present invention need to be administered via ICV delivery to achieve equipotent effect, as compared to systemic administration.

[0057] In some embodiments, the pharmaceutical composition includes a pharmaceutically acceptable carrier. By "pharmaceutically acceptable carrier" is meant any material which, when combined with an active ingredient, allows the ingredient to retain biological activity and does not provoke an unacceptable immune response (e.g., a severe allergy or anaphylactic shock) based on the knowledge of a skilled practitioner. Examples include, but are not limited to, any of the standard pharmaceutical carriers such as phosphate buffered saline solutions, water, and various types of wetting agents. Compositions comprising such carriers are formulated by well known conventional methods (see, for example, Remington's Pharmaceutical Sciences, 18th edition, A. Gennaro, ed., Mack Publishing Co., Easton, PA, 1990; and Remington, The Science and Practice of Pharmacy 20th Ed. Mack Publishing, 2000, which are each hereby incorporated by reference in their entireties, particularly with respect to formulations).

[0058] In some embodiments, the pharmaceutical compositions includes a buffer (e.g. , neutral buffered saline, phosphate buffered saline, etc), a carbohydrate (e.g., glucose, mannose, sucrose, dextran, etc), an antioxidant, a chelating agent (e.g., EDTA, glutathione, etc.), a preservative, another compound useful for treating epilepsy, an inactive ingredient (e.g., a stabilizer, filler, etc), or combinations of two or more of the foregoing. In some embodiments, the composition is formulated as a lyophilizate.

[0059] In some embodiments, felbamate may exhibit increased stability and/or solubility at acid or alkaline pH and may be administered in such form. In other embodiments, a physiologically suitable pH (e.g., in the range of about pH 1.2-1 A) may be used for ICV administration. It may be desirable in some cases to develop aqueous formulations in which felbamate is formulated with a solubility enhancing agent or stabilizing excipient at a physiologically suitable pH. If titration is desired, any suitable buffer known in the pharmaceutical arts may be used (e.g., phosphate, acetate, glycine, citrate, imidazole, TRIS, MES, or MOPS). [0060] Further it may be desirable to maintain physiological isotonicity. For instance, in certain embodiments, an osmolality ranging from about 100 to about 1000 mmol/kg, more particularly from about 280 to about 320 mmol/kg, may be desired. Any suitable manner of adjusting osmolality known in the pharmaceutical arts may be used, e.g., adjustment with NaCl.

[0061] In certain embodiments, felbamate is solubilized in saline at pH 7.4 by including various optional solubilizing agents/stabilizing excipients in the formulation. In certain embodiments, compositions of felbamate (and an optional second therapy) remain in solution and maintain chemical integrity (e.g., less than about 10% degradation, less than about 5% degradation, less than about 2% degradation, etc.) for at least about 1, 2, 3, 4, 5, 6, or more months at physiological temperatures (e.g., about 37 ⁰C), thereby providing suitable formulations for chronic ICV administration in accordance with certain aspects of the invention.

[0062] By way of non-limiting example, mass spectrometry may be utilized to assess the chemical stability of felbamate in the composition under conditions to simulate chronic ICV administration. By way of non-limiting example, such conditions include, e.g., physiological pH at about 37°C for at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, etc.

[0063] Exemplary formulations of felbamate include felbamate cyclodextrin (CDEX) (such as at 10 mg/ml), felbamate PEG, and felbamate in dimethylsulfoxide (DMSO) (such as felbamate 10 mg/mL in DMSO, and felbamate 100 mg/mL in DMSO). The maximum solubility of felbamate in PEG is about 150 mg/ml. Felbamate PEG formulation may have a concentration of felbamate between about 0.1 mg/ml to about 150 mg/ml, about 1 mg/ml to about 150 mg/ml, about 5 mg/ml to about 150 mg/ml, about 10 mg/ml to about 150 mg/ml, about 50 mg/ml to about 150 mg/ml, or about 100 mg/ml to about 150 mg/ml. Any polyethylene glycol (such as PEG 300, PEG 400, and PEG 600) may used. The maximum solubility of felbamate in DMSO is about 450 mg/ml. Felbamate DMSO formulation may have a concentration of felbamate between about 0.1 mg/ml to about 450 mg/ml, about 1 mg/ml to about 450 mg/ml, about 10 mg/ml to about 450 mg/ml, about 50 mg/ml to about 450 mg/ml, about 100 mg/ml to about 450 mg/ml, about 200 mg/ml to about 450 mg/ml, about 300 mg/ml to about 450 mg/ml, or about 400 mg/ml to about 450 mg/ml. Exemplary Second Therapies

[0064] In some embodiments, the pharmaceutical composition includes a second therapy (in addition to felbamate) that is useful for treating a condition for which treatment with felbamate is beneficial (such as epilepsy, e.g., refractory epilepsy) or is useful for treating a side-effect of felbamate. By way of non-limiting example, such agents include anti-epilepsy agents that act on the GABA system, a sodium channel, and/or a calcium channel. Any suitable synergistic or collaborative therapy known in the art may be used.

[0065] Additional active agents are shown in Table 1 below, along with certain physical properties useful in selecting suitable solubility enhancing agents and/or stabilizing excipients. As generally understood by those skilled in the art, the listing of an active agent includes pharmaceutically acceptable salts, esters, and acids thereof. Other exemplary second therapies include Adenosine, Adenosine 1 and 2 receptor analogues, Tegretol, Lamictal, Bumex and other loop diuretics, and Valproate.

Table 1: Exemplary Active Agents

Name Chemical Name Comments Exemplary Indications

VALPROIC ACID 2-Propylpentanoic acid Addiction; Pain Disorders; Anxiety; Depression; Schizophrenia; Bipolar Disorder; Epilepsy

CARBAMEZAPINE 5-carbamoyl-5H- Addiction; Pain dibenz[b,f]azepine Disorders; Depression; Schizophrenia; Bipolar Disorder; Epilepsy

FLURAZEPAM 7-chloro-l-[2- Soluble in water, in Addiction; Pain (diethylamino)ethyl]-5-( o - alcohol, and in 0. IN Disorders; Anxiety; fluorophenyl)- 1, 3 -dihydro-2 H hydrochloric acid. Schizophrenia; Bipolar - 1 ,4-benzodiazepin-2-one Disorder; Epilepsy dihydrochloride

CLONAZEPAM 5-(2-chlorophenyl)-l,3- Addiction; Pain dihydro-7-nitro-2H- 1,4- Disorders; Anxiety; benzodiazepin-2-one Schizophrenia; Bipolar Disorder; Epilepsy

Name Chemical Name Structure Comments Exemplary Indications practically insoluble in Addiction; Pain water and soluble in Disorders; Anxiety; alcohol and in acetone Schizophrenia; Bipolar Disorder; Epilepsy

Addiction; Pain Disorders; Anxiety; Schizophrenia; Bipolar Disorder; Epilepsy

C10H20N2S4 Addiction; Pain Disorders; Anxiety; Schizophrenia; Bipolar Disorder; Epilepsy

Name Chemical Name Structure Comments Exemplary

Indications PHENYTOIN 5,5-diphenyl-2,4- Very soluble in water Epilepsy imidazolidinedione

ESTAZOLAM 8-chloro-6-phenyl-4H-s- Epilepsy triazolo[4,3-α]

[ 1 ,4]benzodiazepine

PHENOBARBITAL 5-Ethyl -5-phenylbarbituric Very soluble in water Epilepsy acid (C12H12N2O3)

Name Chemical Name Structure Comments Exemplary Indications HALAZEPAM 7-Chloro-l,3-dihydro-5- Epilepsy phenyl-1 -(2,2,2- trifluoroethyl)-2H- 1,4- benzodiazepin-2-one

KETAZOLAM 11 -Chloro-8, 12b-dihydro-2,8- Practically insoluble in Epilepsy dimethyl- 12b-phenyl-4H- water; slightly soluble

[l,3]oxazino[3,2- in alcohol; freely d] [ 1 ,4]benzodiazepine- soluble in chloroform

4,7(6H)-dione

QUAZEPAM 7-Chloro-5-(2-fluorophenyl)- Epilepsy l,3-dihydro-l-(2,2, 2- trifluoroethyl)- 1,4- benzodiazepine-2-thione.

Name Chemical Name Structure Comments Exemplary Indications PRAZEPAM 7-Chloro-l- Slightly soluble in Epilepsy

(cyclopropylmethyl)-l,3- water; freely soluble in dihydro-5-phenyl-2H- 1 ,4- chloroform and in benzodiazepin-2-one methyl alcohol; practically insoluble in isooctane

TEMAZEPAM 7-chloro- 1 ,3 -dihydro-3 - Epilepsy hydroxy- 1 -methyl-5 -phenyl- 2H-l,4-benzodiaz epin-2-one

oo

C_1SH_1SCIN₂O₂ MoI. wt 300,74

NITRAZEPAM 1 ,3-Dihydro-7-nitro-5-phenyl- Soluble 1 in 12 of Epilepsy 2H- 1 ,4-benzodiazepin-2-one water, 1 in 14 of alcohol, and 1 in 3.5 of chloroform; insoluble in ether; freely soluble in methyl alcohol

DIAMOX N-(5-Sulfamoyl-l,3,4- Epilepsy thiadiazol-2-yl)acetamide

Name Chemical Name Structure Comments Exemplary Indications CARBATROL 5H-dibenz[b,f]azepine-5- Slightly soluble in Epilepsy carboxamide water and in alcohol

DIASTAT 7-chloro- 1 ,3 -dihydro- 1 - Epilepsy methyl-5-phenyl-2H- 1 ,4- benzodiazepin-2-one

>o FELBAMATE 2-phenyl-l,3-propanediol Freely soluble in water Epilepsy (FELBATOL) dicarbamate and in alcohol; soluble in acetone; insoluble in ether and in benzene

Exemplary Cyclodextrins

[0066] In some embodiments, the pharmaceutical composition includes one or more cyclodextrins, e.g., β-hydroxypropyl-cyclodextrin (HPBCD) or sulfobutyl-ether-β cyclodextrin. In particular, the hydrophobicity of felbamate makes it difficult to formulate in aqueous dosage forms for ICV administration with physiological tonicity and pH. Formulations for ICV use are further complicated by the need for high concentrations within the injection device so that small injection volumes can attain therapeutic drug levels within the CSF. The use of organic solvents (e.g., octanol) are clearly unsuitable for ICV injection. Consequently, cyclodextrin can be used a means of allowing high felbamate concentrations (such as about 10 mg/m/L) to be formulated at physiological pH. Cyclodextrins are potent solubilizers because they possess both nonpolar and hydrophilic moieties that aid in the solubilization process. The nonpolar portion of these solubilizing agents interacts with hydrophobic drugs, while their hydrophilic moieties interact with water molecules to enhance solubility.

[0067] Amphiphilic agents possessing stronger hydrophobic character have the potential to interact with cell membranes and produce toxic effects. Thus, in some embodiments, HPBCD is used as the cyclodextrin since it has minimal hydrophobic character, and hence greater potential for better tolerability under conditions of chronic administration. HPBCD cyclodextrins may have low toxicity since the hydrophobic pocket of these circular molecules can interact with individual felbamate molecules while being relatively inaccessible to large membranous structures. In addition, toxicity is likely to be reduced if the formulation components are readily degraded in a cellular environment. The ability of cells to degrade compounds prevents their accumulation during chronic administration. To this end, HPBCD contains chemically labile ether and ester linkages that can reduce or prevent significant cellular accumulation during chronic ICV injection. If desired, the toxicity profile of the HPBCD excipient administered via the ICV route can be assessed using standard methods.

[0068] Any suitable amount of cyclodextrin sufficient to solubilize felbamate to the desired concentration may be used. In certain embodiments, molar ratios of felbamate to cyclodextrin ranging from about 1 :1 to about 1 :10, particularly, about 1 :1 to about 1:5, more particularly about 1 :1 to about 1 :2, about 1 :2 to about 1 :3, or about 1 :3 to about 1 :4, may be used to achieve adequate solubility of felbamate to the desired concentrations. In particular embodiments, the molar ratio of felbamate to cyclodextrin is about 1 :3. [0069] In some embodiments, the pharmaceutical composition contains between about 1 to about 40% cyclodextrin (w/w), such as about 1 to about 5%, about 5 to about 10%, about 10 to about 15%, about 15 to about 20%, about 20 to about 25%, about 25 to about 30%, about 30 to about 35%, or about 35% to about 40%. In certain embodiments, the pharmaceutical composition contains between about 5 to about 30%, about 10 to about 30%, or about 20 to about 30% cyclodextrin (w/w). In particular embodiments, the pharmaceutical composition contains about 12, 13, 14, 15, 16, 17, 18, 19, or 20% cyclodextrin (w/w). In certain embodiments, the pharmaceutical composition contains about 16.5% cyclodextrin (w/w). In certain embodiments, the amount of cyclodextrin is low enough to prevent the viscosity of the pharmaceutical composition from being too high.

Exemplary Stabilizing Excipients

[0070] In addition to having sufficient solubility, felbamate must be sufficiently stable within the composition to withstand hydrolytic and oxidative degradation in order to maintain biological activity during ICV administration. The stability of the drug in the composition prior to ICV administration is also of importance. To this end, in certain embodiments, the compositions of the present invention may further include a stabilizing excipient and/or buffer.

[0071] Considering that oxidation represents a common degradation pathway, in certain aspects, the compositions of the invention may be deoxygenated (e.g., by saturating with nitrogen gas) to minimize the formation of reactive oxygen species that would degrade felbamate during storage. Another method would be to ensure that formulations are stored in a container that does not allow passage of light, thereby minimizing photo-induced degradation. Clearly, both the removal of oxygen and protection from light can be easily accomplished in a device designed for use in chronic ICV administration. In addition, in accordance with certain aspects of the invention, stabilizing excipients may optionally be used to, e.g. , prevent or slow degradation by oxidation and/or hydrolysis of felbamate. For example, vitamin E, methionine, chelators, or mannitol may be used to reduce oxidative degradation. Since the rates of many degradation reactions are pH-dependent, such formulations may include any suitable buffering agent known in the art (e.g., phosphate, acetate, glycine, citrate, imidazole, TRIS, MES, or MOPS). [0072] Stabilizing excipients useful in the context of the compositions described herein include any pharmaceutically acceptable components which function to enhance the physical stability, and/or chemical stability of felbamate in the compositions of the invention. The pharmaceutical compositions described herein may include one or more stabilizing excipient, and each excipient may have one or more stabilizing functions.

[0073] In one aspect, the stabilizing excipient functions to stabilize felbamate against chemical degradation, e.g., oxidation, deamidation, deamination, or hydrolysis. In this regard, the stabilizing excipients may optionally be selected from antioxidants, such as ascorbic acid (vitamin C), vitamin E, tocopherol conjugates, tocopherol succinate, PEGylated tocopherol succinate, Tris salt of tocopherol succinate, Trolox, mannitol, sucrose, phytic acid, trimercaprol, and glutathione. In some embodiments, an optional antioxidant of modified vitamin E compounds, (e.g., Trolox or PEG-Tocopherol succinate) at about 50 micrograms/mL to about 1 mg/mL is included in the pharmaceutical composition.

Penetration Enhancing Excipients

[0074] The compositions of the invention may further include optional penetration enhancing excipients. Such penetration enhancing excipients may include any pharmaceutically acceptable excipient known in the art which is capable of maintaining felbamate within the brain or CSF, or otherwise maximizing the active agents residence time in the brain or CSF. In certain aspects, such excipients may act to decrease drug resistance. For instance, the penetration enhancing excipients may act to avoid, bind, or otherwise mask glycoprotein pumps which act to clear felbamate from the brain or CSF. Again, any suitable excipient capable of maintaining felbamate in the brain or CSF, or otherwise maximize brain or CSF residence time may be used.

Exemplary Treatment Methods

[0075] In another aspect, methods of using any of the pharmaceutical compositions described herein are provided. The methods generally comprise ICV delivery of a pharmaceutical composition described herein (e.g., a composition with between about 1 mg to about 180 mg of felbamate and a cyclodextrin) to an individual (e.g., a human) in need thereof. In some embodiments, the total daily dose of felbamate for the human is between about 1 mg to about 180 mg of felbamate, such as between about 10 mg to about 40 mg of felbamate. The methods can be used in any therapeutic or prophylactic context in which felbamate may be useful. By way of non-limiting example, the methods may include treating a condition for which treatment with felbamate is beneficial (such as epilepsy, e.g., refractory epilepsy).

[0076] In some embodiments, the method is used to treat partial or focal onset seizures, such as simple partial seizures or complex partial seizures. In some embodiments, the method is used to treat generalized seizures, such as absence (petit mal), myoclonic, clonic, tonic, tonic-clonic (grand mal), or atonic seizures. In various embodiments, the method is used to treat infantile spasms (West syndrome), childhood absence epilepsy, Dravet's syndrome, a benign focal epilepsy of childhood (such as benign childhood epilepsy with centro-temporal spikes, benign rolandic epilepsy, or benign childhood epilepsy with occipital paroxysms), juvenile myoclonic epilepsy, temporal lobe epilepsy, fetal alcohol syndrome, frontal lobe epilepsy, Lennox-Gastaut syndrome, occipital lobe epilepsy, or any combination of two or more of the foregoing. In some embodiments, the method involves treatment of severe partial onset seizures with or without secondary generalization in individuals who have failed adequate 1, 2, 3, 4, or more oral drug treatment regimens.

[0077] The methods of the present invention can be used to treat any individual. For use herein, unless clearly indicated otherwise, "an individual" as used herein intends a mammal, including but not limited to, a primate (e.g., a human, monkey, gorilla, ape, lemur, etc.), a bovine, an equine, a porcine, a canine, and a feline. Thus, the invention finds use in both human medicine and in the veterinary context, including use in agricultural animals and domestic pets. The individual may have been diagnosed with, is suspected of having, or is at risk of developing an indication for which treatment with felbamate is beneficial, such as epilepsy. The individual may exhibit one or more symptoms (such as seizures) associated with the indication. The individual can be genetically or otherwise predisposed to developing such a condition.

[0078] In some embodiments, the individual (such as a human) has refractory epilepsy. In some embodiments, wherein the individual is selected from the population of individuals who are refractory to treatment via oral or systemic administration of a compound for the treatment of epilepsy other than felbamate. In some embodiments, the individual has not responded to 1, 2, 3, 4, or more compounds (administered as separate monotherapies or as combination therapies) for the treatment of epilepsy (such as anti-epilepsy agents other than felbamate) prior to treatment with a method of the invention. In some embodiments, the individual has seizures that have not be adequately controlled by 1, 2, 3, 4, or more compounds for the treatment of epilepsy (such as anti-epilepsy agents other than felbamate) prior to treatment with a method of the invention. In some embodiments, the individual is selected from the population of individuals who are refractory to treatment via oral or systemic administration of felbamate. In some embodiments, the individual has failed surgical treatment (such as vagus nerve stimulation) or has been determined to not have a surgical option for treatment. In various embodiments, the individual has at least 1, 2, 3, 4, 5, 6, or more complex partial or generalized tonic-clonic seizures per month for at least 1, 2, 3, 4, 5, 6, or more months prior to treatment with a method of the invention.

[0079] As used herein, "in need thereof includes individuals who have a condition or disease for which treatment with felbamate is beneficial, such as epilepsy or are "at risk" for the condition or disease. As used herein, an "at risk" individual is an individual who is at risk of development of a condition for which treatment with felbamate is beneficial, such as epilepsy. An individual "at risk" may or may not have a detectable disease or condition, and may or may not have displayed detectable disease prior to the treatment methods described herein. "At risk" denotes that an individual has one or more so-called risk factors, which are measurable parameters that correlate with development of a disease or condition and are known in the art. An individual having one or more of these risk factors has a higher probability of developing the disease or condition than an individual without these risk factor(s). These risk factors include, but are not limited to, age, sex, race, diet, history of previous disease, presence of precursor disease, genetic {i.e., hereditary) considerations, and environmental exposure. Methods for the diagnosis of epilepsy, as well as procedures for the identification of individuals at risk for developing epilepsy, are well known to those in the art. Such procedures may include clinical tests, physical examination, personal interviews, and assessment of family history.

[0080] These methods can be used to treat any condition for which treatment with felbamate is beneficial, such as epilepsy. By "treatment" or "treating" is meant an approach for obtaining a beneficial or desired result, including clinical results. For purposes of this invention, beneficial or desired results include, but are not limited to, alleviation of symptoms (such as seizures) associated with a condition (such as, but not limited to, epilepsy), diminishment of the extent of the symptoms associated with a condition (such as the severity or duration of seizures), delaying the development of a condition, or prevention of a worsening of the symptoms associated with a condition. In some embodiments, treatment with a one or more pharmaceutical compositions disclosed herein is accompanied by no or fewer side-effects than are associated with currently available therapies.

[0081] As used herein, "delaying" development of a disease or condition means to defer, hinder, slow, retard, stabilize and/or postpone development of the disease or condition for which treatment with felbamate is beneficial, such as epilepsy. This delay can be of varying lengths of time, depending on the history of the disease and/or individual being treated. As is evident to one skilled in the art, a sufficient or significant delay can, in effect, encompass prevention, in that the individual does not develop the disease or condition. For example, the method may reduce the probability of disease development in a given time frame and/or reduce the extent of the disease in a given time frame, when compared to not using the method. In some embodiments, such comparisons are based on clinical studies using a statistically significant number of subjects. Disease development can be detectable using standard clinical techniques. Development may also refer to disease progression that can be initially undetectable and includes occurrence, recurrence, and onset.

[0082] In some embodiments, any of the methods described herein produce a percentage reduction in total seizure frequency of at least about any of 10, 20, 30, 40, 50, 60, 70, 80, 90, 95, or 100% compared to the seizure frequency in the same individual prior to treatment or compared to the seizure frequency in other individuals not receiving the treatment. In some embodiments, any of the methods described herein produce fewer adverse events, greater tolerability, and/or a greater improvement in other secondary clinical measures (such as Clinical Global Impression (CGI), Quality of Life (QOLIE-31; SF-36), or mood) compared to oral administration of felbamate.

Exemplary Routes of Administration

[0083] Desirably, the methods used to administer felbamate maximize the amount of felbamate (or a metabolite thereof) delivered to one or more areas of the brain associated with epilepsy in an individual and minimize (i) the amount of felbamate (or a metabolite thereof) delivered to other areas of the brain and/or (ii) the amount of felbamate that is cleared from the brain or nervous system. Delivery of felbamate to specific regions of the brain improves bioavailability, reduces systemic toxicity, improves patient compliance, and facilitates complex dosing regimens. Standard methods of quantifying how fast and how far felbamate has penetrated into the brain are the basis for the "coefficient of penetration" and can be used to understand how much felbamate is getting into the tissue of interest (Blasberg et al. 1975, 1977, Collins et al. 1983). Standard methods can be used to determine the region(s) of the brain (such as the temporal lobe) associated with epilepsy in a particular individual using techniques such as MRI or PET scanning.

[0084] In some embodiments, the activity of felbamate is substantially local to the delivery site within the CSF. Bernards et al. (Cerebrospinal Fluid and Spinal Cord Distribution of Baclofen and Bupivacaine during Slow Intrathecal Infusion in Pigs, Pain And Regional Anesthesia Anesthesiology. 105(l):169-178, July 2006) studied slow drug administration into the spinal CSF and found that both hydrophobic and hydrophilic compounds bind within ~1 cm of the local area of drug administration. In addition, CSF flow from the lumbar cistern differs from supratentorial CSF flow in that it tends to be slower, and likely does not go through the ventricles or equilibrate with supratentorial CSF compartments (Kroin et al, The Distribution of Medication along the Spinal Canal after Chronic Intrathecal Administration. Neurosurgery. 33(2):226-230, August 1993). As such, without intending to be limited by theory, felbamate may be administered in close proximity to the location(s) in the brain of a particular individual that are associated with epilepsy in that individual. For example, the ICV delivery device may be advantageously placed in close proximity to the desired location for therapeutic activity of felbamate.

[0085] One aspect of the present invention relates to the ICV administration of felbamate (administration into one or more cerebral ventricles). In some embodiments, felbamate is administered to only one cerebral ventricle. In some embodiments, felbamate is administered to more than one cerebral ventricle (such as 2, 3, or 4 cerebral ventricles). In certain embodiments, felbamate is administered to the third and/or fourth cerebral ventricle. In certain embodiments, felbamate is administered to one or both lateral cerebral ventricles.

[0086] In some embodiments, any of the methods described herein also include administering felbamate by a second route of administration other than ICV administration. In some embodiments, the second route of administration involves administration of felbamate to the lumbar cistern and/or cisterna magna. In some embodiments, a lumbar placed catheter in the cisterna magna is used to administer felbamate. In some embodiments, felbamate is administered by 1, 2, 3, 4, or more different routes of administration. [0087] In some embodiments, felbamate is administered by an ICV route of administration and a second route of administration simultaneously. The term "simultaneous administration" in reference to two routes of administration, as used herein, means that a therapy (such as felbamate) is administered by two different routes of administration with a time separation of no more than about 15 minutes, such as no more than about any of 10, 5, or 1 minutes.

[0088] In some embodiments, felbamate is administered by an ICV route of administration and a second route of administration sequentially. As used herein, the term "sequential administration" in reference to two routes of administration means a therapy (such as felbamate) is administered by two different routes of administration with a time separation of more than about 15 minutes, such as more than about any of 20, 30, 40, 50, 60 or more minutes. Either route of administration may be used first. For example, felbamate can first be administered by an ICV route of administration and then administered by a different route of administration. Or felbamate can first be administered by a route of administration other than ICV administration and then administered by an ICV route of administration.

[0089] For some embodiments of concurrent administration, the administration of felbamate by an ICV route of administration overlaps the administration of felbamate by a second route of administration. In other embodiments, the administration is non-concurrent. For example, in some embodiments, the ICV administration of felbamate is terminated before the felbamate is administered by a second route of administration. In some embodiments, the administration by a route of administration other than ICV delivery is terminated before felbamate is administered by an ICV route of administration. For sequential administration, there is preferably a time period while felbamate in both administered locations simultaneously exerts its biological activities. Thus, felbamate may be administered by an ICV route of administration prior to, during, or following administration by a second route of administration. In various embodiments, the timing between the ICV administration of felbamate and the delivery by a second route of administration is about 1 month or less, about 2 weeks or less, about 1 week or less, about 3 days or less, about 1 day or less, about 12 hours or less, about 6 hours or less, about 4 hour less, or about 2 hours or less.

[0090] In some embodiments, the ratio of the amount felbamate administered by an ICV route of administration to the amount felbamate administered by a second route of administration is less than or about any of 100:1, 50:1, 30:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, and 1:1 In some embodiments, the ratio of the amount felbamate administered by an ICV route of administration to the amount felbamate administered by a second route of administration is more than about any of 1 :1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 30:1, 50:1, 100:1. In some embodiments, the amount felbamate administered by lumbar injection is about 100%, 200%, 500%, or more than the amount of felbamate administered by ICV delivery. Other ratios are contemplated.

[0091] In some embodiments, the method also involves administering a second therapy (in addition to felbamate) that is useful for treating a condition for which treatment with felbamate is beneficial (such as epilepsy, e.g., refractory epilepsy) or is useful for treating a side-effect of felbamate. This second therapy can be administered using any appropriate route of administration. In various embodiments, any suitable manner of central administration known in the art is used, e.g., intrathecal delivery, intrathecal (administration into the cerebrospinal fluid-containing space), spinal or lumbar delivery into the subarachnoid space, intracranial delivery (administration into the brain parenchyma), ICV delivery, or delivery to the lumbar cistern and/or cisterna magna. In some embodiments, the second therapy is administered by 1, 2, 3, 4, or more different routes of administration.

[0092] In some embodiments, felbamate and the second therapy are administered simultaneously. The term "simultaneous administration" in reference to the administration of two different therapies, as used herein, means that a first therapy (such as felbamate) and a second therapy (such as an anti-epilepsy agent other than felbamate) in a combination therapy are administered with a time separation of no more than about 15 minutes, such as no more than about any of 10, 5, or 1 minutes. When the compounds are administered simultaneously, the first and second therapies may be contained in the same composition (e.g., a composition comprising felbamate and another anti-epilepsy agent) or in separate compositions (e.g., felbamate is contained in one composition and another anti-epilepsy agent is contained in another composition).

[0093] In some embodiments, felbamate and the second therapy are administered sequentially. As used herein, the term "sequential administration" in reference to the administration of two different therapies means that the first therapy and second therapy in a combination therapy are administered with a time separation of more than about 15 minutes, such as more than about any of 20, 30, 40, 50, 60 or more minutes. Either the first therapy or the second therapy may be administered first. The first and second therapies are contained in separate compositions, which may be contained in the same or different packages or kits.

[0094] For some embodiments of concurrent administration, the administration of felbamate overlaps the administration of the second therapy. In other embodiments, the administration is non-concurrent. For example, in some embodiments, the administration of felbamate is terminated before the second therapy is administered. In some embodiments, the administration of the second therapy is terminated before felbamate is administered. For sequential administration, there is preferably a time period while both (or all) pharmaceutically active compounds simultaneously exert their biological activities. Thus, felbamate may be administered prior to, during, or following administration of the second therapy. In various embodiments, the timing between at least one administration of felbamate and at least one administration of the second therapy is about 1 month or less, about 2 weeks or less, about 1 week or less, about 3 days or less, about 1 day or less, about 12 hours or less, about 6 hours or less, about 4 hour less, or about 2 hours or less. In another embodiment, felbamate and the second therapy are administered concurrently to an individual in a single formulation or separate formulations.

[0095] The administration of felbamate and/or the optional second therapy may be acute or chronic, and may be via injection, infusion, pump, implantable pump, etc.

[0096] In accordance with certain aspects of the invention, establishing drug efficacy in the central nervous system through ICV administration may be maximized using several strategies. Felbamate and/or another anti-epilepsy agent are likely to be more ideally suited to administration into the ventricle of the brain or the cisterna magna than into the spine. For instance, anti-epilepsy agents may need greater exposure to the brain in the cranium than via the spinal canal. Epilepsy may be more effectively treated by tighter control of dosing regimens for CSF delivery. For example, administering felbamate before waking may eliminate a patient's seizures that occur on waking in the morning. Women who have seizures at their menstrual period can be given higher level of medication for the 5-7 days around their period than at other times of the month to maximize medication efficacy.

[0097] Dosing strategies also incorporate various approaches to initiating treatment, stopping treatment, switching treatment, and responding to different patient states. These various dosing strategies can be selected by a manual adjustment of a computer program and/or algorithm. Different initiating treatments include rapid initiation, moderate initiation, or slow initiation. Altered initial dosing patterns may be necessary due to such issues as central side-effect profiles which may necessitate slower loading. Patients with this approach may differ because of the central side-effect profile which may necessitate slower loading. Patients may need to have rapid or slow medication taper depending on side-effect issues and patient safety. Reasons for performing a rapid taper include reacting to a medication allergy or cross-taper with initiation of another treatment. One reason for a slow taper might be mediate seizures that caused by rapid withdrawal. Certain reasons to initiate special approaches to treatment might be seizures where a family member or patient might wish to give extra doses for auras or ongoing seizure where an extra dose of medication should appropriately be applied.

[0098] Examples of manual or programmed dosing modes or strategies include night time administration, administration before waking, increased administration one week a month, three times a day, continuous dosing, bolus dosing, taper dosing, need based dosing, feedback dosing by the physician, provider, patient or family. The clinical scenarios where these can be employed include chronic disease, disease exacerbation, need for suppression treatment, need for recurrence treatment, or increase in frequency of seizures.

[0099] Toxicity due to local delivery to the CNS can be minimized or prevented by using computer programming to identify a precise dosing amount that is within the therapeutic window. This amount could be determined by clinical response and complaints, electrophysiological tests like EEG, EP, or MEG or by scanning like MRI and PET scanning.

[0100] Another problem with long term administration is total dosing wherein drug toxicity is cumulative. Solutions include limiting the total amount of drug delivered by strictly limiting the dosing period, reducing the dosage, or potentially taking a drug holiday.

[0101] A third issue that comes up in toxicology has to do with local drug effects of the medication and its accompanying excipient. Medications administered into the fluid around the brain might be more toxic in the fluid above the spinal cord than if administered in the ventricle. An example of this is that an excipient which might be administered in a 20% concentration in the pump might be able to be diluted 1000 fold in the ventricle versus 10 fold in the spinal fluid because of the relatively different volumes in the spinal cord area (approximately 100 micro liters) versus in the ventricle (approximately 7cc). Solutions to this dilution problem would present themselves by administering the medication in the ventricle or in the cisterna magna if a greater amount of fluid is required for more complete dilution.

[0102] Another facet of local drug effect is pH. Available data suggests that it is safe to inject a small amount of weakly buffered or unbuffered, very low pH drug (pH 2.0). However, some minimal buffering capacity is advantageous to maintain pH-dependent solubility in the pump reservoir. This is counterintuitive to many experts who would assume that normal pH is a requirement of intra CSF administration.

[0103] Toxicology experiments can be constructed in vitro and in vivo to prepare for medications administered in the CSF. Initial in vitro toxicology work for CSF based drug delivery involves testing whether medication/excipient combinations cause cell death, oxidation, or other metabolic changes. In vitro experiments ideally are performed in two animal species, such as the rat and the dog experiments described herein. The rat is a good for preliminary testing because of availability of dosing to 28 days but the volume of the ventricle is very small and therefore less dilution occurs than in human ventricular delivery. The dog offers the capacity for 90 day drug testing using an implanted catheter and a pump that is carried on the animal's body.

[0104] In some embodiments, fenestration of the septum pellucidum is performed using standard methods to facilitate higher or equal bilateral tissue distribution of felbamate and/or a second therapy for the treatment of epilepsy {see, for example, Gangemi et al. , Endoscopic surgery for monoventricular hydrocephalus, 52(3):246-50; discussion 250-1, 1999 Sep, which is herein incorporated by reference in its entirety, particular with respect to fenestration methods).

[0105] In some embodiments, administration can be a prophylactic treatment, beginning concurrently with the diagnosis or observation of condition(s) {e.g., lifestyle, genetic history, surgery, etc.) which places a subject at risk of developing a specific disease or disorder. In the alternative, administration can occur subsequent to occurrence of symptoms associated with a specific disease or disorder.

[0106] In certain aspects, felbamate is administered ICV over a predetermined duration of time, and the composition is formulated so as to maintain solubility and stability over the predetermined time period and conditions of use {e.g., physiological pH, temperature, and/or tonicity, etc.). The duration of time may be, e.g., at least about 1 month, at least about 2 months, at least about 3 months, at least about 4 months, at least about 5 months, at least about 6 months, etc.

[0107] Exemplary dosing frequencies include, but are not limited to, at least 1, 2, 3, 4, 5, 6, or 7 times (i.e., daily) a week. In some embodiments, felbamate is administered at least about any of 2, 3, 4, or 6 times a day. In some embodiments, felbamate is administered continuously. Felbamate is be administered, e.g., over a period of a few days or weeks. In some embodiments, felbamate is administrated for a longer period, such as a few months or years. The dosing frequency of the composition may be adjusted over the course of the treatment based on the judgment of the administering physician.

Exemplary Implantable Pumps

[0108] In certain preferred embodiments, the administration is via an implantable pump, e.g., an ICV or subarachnoid delivery device for chronic administration. By way of non- limiting example, devices such as those disclosed in U.S. Patent Publication 2004/0133184, which is herein incorporated by reference in its entirety, may be used.

[0109] Continuous administration may be achieved using an implantable or attachable pump controlled delivery device, such as those marketed by Medtronic, Inc. However, any implanted controlled delivery device known in the art may be used. Certain embodiments involve using an implanted catheter pump system for at least one month, at least about two months, at least about three months, at least about 4 months, at least about 5 months, at least about 6 months, etc. of chronic ICV administration.

[0110] The pump may be implanted as currently approved in the product labeling. Although the spinal catheter is approved for use in intrathecal drug delivery with the Synchromed pump and not as yet for ICV modes of drug delivery, the approved spinal catheter has been used successfully by several clinicians for ICV administration of drugs (e.g., in pediatric patients).

[0111] In some embodiments, stealth technology is used for catheter placement using standard methods. Standard interoperative navigation methods can be used to insert the catheter into the desired location within the brain for administration of felbamate. [0112] The Medtronic Synchromed II Pump is implanted in a 45-minute procedure performed by anesthesiologists, neurosurgeons, and general surgeons. The pump is located in the abdomen and the catheter is placed into the CSF through a spinal tap. The catheter lies outside the spinal cord tissue and medication is administered from the tip of the catheter.

[0113] In some embodiments, ICV administration of felbamate involves placing a 4 mm hole in the cranium through which a tube is placed. Placement of a small cranial hole for a hollow tube insertion is a frequently performed neurosurgical procedure and has a very low risk of any complication including major complications of epilepsy, stroke, hemorrhage or death (Lamer, TJ. "Treatment of cancer-related pain: when orally administered medications fail," Mayo Clin Proc\994; 69:473-80).

[0114] The pump drug reservoir is designed for refill at approximately 3 month intervals, dependent upon patient dosing requirements. In clinical practice with other medications administered with the pump, physicians (or their nursing and physician assistants) program and refill the pump. Typical follow-up after a pump placement is 1 week, with a second visit 1 month later. Usually patients are seen at a maximum of once per week for programmable dose adjustment in the first two to three months and thereafter every three months unless symptoms or medication side-effects require programming adjustment of the drug dose.

[0115] ICV delivery of felbamate with an implantable pump could potentially minimize/eliminate peripheral side-effects (dramatic dose reduction), while optimizing compliance through continuous drug delivery. This approach may help establish felbamate as a more effective drug, by potentially limiting its well known side-effects and thereby expanding the patient pool for whom this drug may be useful.

[0116] In some embodiments, injection is continuous, using a computerized pump to provide a delivery rate of about 0.01 to about 1 mg of felbamate per hour, depending on the severity of symptoms. CSF concentration is periodically monitored and the delivery rate is adjusted accordingly to provide a steady-state concentration of about 1 to about 50 micrograms per milliliter of cerebrospinal fluid.

Exemplary Dosing Regimens

[0117] In some embodiments, the pharmaceutical composition contains an effective amount of felbamate. In some embodiments, the pharmaceutical composition contains an effective amount of a second therapy (in addition to felbamate) that is useful for treating a condition for which treatment with felbamate is beneficial (such as epilepsy, e.g., refractory epilepsy) or is useful for treating a side-effect of felbamate. The term "effective amount" intends such amount of one or more therapeutic agents described herein which in combination with its parameters of efficacy and toxicity should be effective in a given therapeutic form based on the knowledge of the practicing specialist. As is understood in the art, an effective amount can be in one or more doses. As is understood in the clinical context, an effective dosage of a pharmaceutical composition may or may not be achieved in conjunction with another drug, compound, or pharmaceutical composition. Thus, an effective amount can be considered in the context of administering one or more therapeutic agents, and a single agent can be considered to be given in an effective amount if, in conjunction with one or more other agents, a desirable or beneficial result can be or is achieved.

[0118] An exemplary total daily dose of felbamate for an individual (e.g. , a human) is between about 1 mg to about 250 mg, such as between about 1 to about 180 mg, between about 1 to about 5 mg, about 5 to about 10 mg, about 10 to about 15 mg, about 15 to about 20 mg, about 20 to about 25 mg, about 25 to about 30 mg, about 30 to about 35 mg, about 35 to about 40 mg, about 40 to about 50 mg, about 50 to about 60 mg, about 60 to about 70 mg, about 70 to about 80 mg, about 80 to about 90 mg, about 90 to about 100 mg, about 100 to about 110 mg, about 110 to about 120 mg, about 120 to about 130 mg, about 130 to about 140 mg, about 140 to about 150 mg, about 150 to about 160 mg, about 160 to about 170 mg, about 170 to about 180 mg, about 180 to about 200 mg, about 200 to about 250 mg. In certain embodiments, total daily dose of felbamate for an individual (e.g., a human) is between about 10 to about 40 mg, about 40 mg to about 100 mg, about 100 mg to about 140 mg, about 140 mg to about 180 mg, or about 180 mg to about 250 mg. In certain embodiments, about 1 mg/ml to about 100 mg/ml of felbamate is administered at about 5 microliters per hour to about 100 microliters per hour. In some embodiments, about any of 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200, 250, 300, 400, 425, or 450 mg/ ml of felbamate is administered. In some embodiments, about any of 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 microliters per hour are administered.

[0119] In certain embodiments, the ICV administered dose to an individual (such as a human) may range from about 0.4% to about 225% of the corresponding systemic administration dosage. In some embodiments, the ICV administered dose to an individual (such as a human) is from about 30-fold lower to about 30-fold higher than the ICV dose in rodents, e.g., the ICV administered dosage in humans is about 30-fold lower to about 30-fold higher than the effective ICV dose in rats. For example, in some embodiments, the dosage administered to an individual (such as a human) is about 30-fold lower to about 30-fold higher than the rodent ICV dose. In some embodiments, the ICV administered dosage is about 20-fold lower to about 30-fold higher, about 10-fold lower to about 30-fold higher, about 10-fold lower to about 20-fold higher, about 10-fold higher to about 10-fold higher, about 10-fold higher, about 20-fold higher, about 30-fold higher, about 10-fold lower, about 20-fold lower, or about 30-fold lower.

[0120] The invention also features methods of determining a dosing regimen for the ICV administration of felbamate to an individual (such as a human). In some embodiments, the dose for ICV administration to the individual (such as a human) is determined by dividing the typical oral dose for the same population of individuals (such as humans with the same type of epilepsy) by about 10 to about 100 (such as dividing the oral dose by about 30 to about 50). For example, if about 3600 mg of felbamate is orally administered per day in an adult human, then the corresponding ICV dose is about 36 to about 360 mg per day in an adult human.

[0121] In some embodiments, the dose for ICV administration to the individual (such as a human) is determined by measuring or estimating the dose required to obtain an intraventricular CSF concentration of free felbamate of between about 20 to about 60 micrograms/microliters, which is the target CSF level in the ventricle, lumbar cistern, or cisterna magna. For example, different doses of increasing amounts could be administered to determine what dose is sufficient to obtain a free felbamate of between about 20 to about 60 micrograms/microliters in a cerebral ventricle, lumbar cistern, or cisterna magna in the individual. In some embodiments, the initial ICV dose is approximately 1/30¹ of the oral dose. Other doses can also be tested.

[0122] In some embodiments, the dose for ICV administration to the individual (such as a human) is determined by measuring or estimating the dose required to obtain about 15 to about 60 micrograms of felbamate per gram of brain tissue in the individual as the target brain concentration for effective treatment. For example, in human adult epilepsy patients, the brain concentrations of felbamate achieved with an oral dose of 3600 mg per day is reported to range from 13 to 73 micrograms per gram of brain tissue. In some embodiments, the target dose for humans is the amount estimated based on extrapolations from large animal ICV administration models to be required to attain a maximum concentration of between about 15 to about 60 ug of felbamate per gram of brain tissue. The dose required for humans relative to that required in animal ICV models is assumed to be proportional to total brain weight. Thus, the predicted target ICV dose in humans is 25 fold greater than that required in beagles (since the adult human brain weight of 1700 g is 25 fold greater than the beagle brain weight of 70 grams). In some embodiments, the amount of felbamate cleared by humans is estimated to be about 2, 3, 4, or 5-fold less than the amount of felbamate cleared by dogs. Brain felbamate concentrations in animals (such as dogs) are estimated from the amount of felbamate infused, minus the amount of felbamate cleared, divided by the brain weight. Thus, the amount of felbamate that remains in the brain of humans divided by the brain weight is desirably between about 15 to about 60 micrograms of felbamate per gram of brain tissue. In some embodiments, the amount of felbamate that remains in the brain of humans divided by the brain weight is desirably between about 29 to about 60 micrograms of felbamate per gram of brain tissue, such as between about 30 to about 35, about 35 to about 40, about 40 to about 45, about 45 to about 50, about 50 to about 55, or about 55 to about 60 micrograms of felbamate per gram of brain tissue.

[0123] In some embodiments for the ICV administration of felbamate, the cortex of the brain of the individual (such as a human) has a felbamate concentration of about 15 to about 60 micrograms of felbamate per gram of brain tissue. In some embodiments, the felbamate concentration in regions of the brain other than the cortex is less than about 15, 10, 5, 3, 2, 1, or 0.5 micrograms of felbamate per gram of brain tissue. In some embodiments, the felbamate concentration in regions of the brain other than the cortex is between about 0.5 to about 10 micrograms of felbamate per gram of brain tissue, such as between about 1 to about 10 or between about 1 to about 5 micrograms of felbamate per gram of brain tissue. In some embodiments, one or more locations in the brain associated with epilepsy in the individual (such as known or suspected epileptogenic zones) have a felbamate concentration of about 15 to about 60 micrograms of felbamate per gram of brain tissue. In some embodiments, white matter and/or other location/region unlikely to be epileptogenic zones have a lower concentration of felbamate (such as less than about 15, 10, 5, 3, 2, 1, or 0.5 micrograms of felbamate per gram of brain tissue). Furthermore, given the pathophysiology of epilepsy related to the temporal lobe, the temporal lobe in some embodiments has a felbamate concentration of about 15 to about 60 micrograms of felbamate per gram of brain tissue. Standard methods, such as those described herein, can be used to measure the amount of felbamate in any tissue of interest (such as cisterna magna, lumbar, CSF, or plasma sampling).

[0124] In some embodiments, the concentrations of the felbamate may vary based on binding sites for felbamate in the brain tissue and critical levels of felbamate may be required at those binding sites. In some embodiments, the felbamate concentration at one or more of these binding sites (such as one or more binding sites in the hippocampus) is about 15 to about 60 micrograms of felbamate per gram of brain tissue. In some embodiments, the felbamate concentration is about 15 to about 60 micrograms of felbamate per gram of brain tissue in one or more locations pertinent to seizure spread or origination of seizure discharge.

[0125] In some embodiments, the dosage is higher than the CNS clearance rate. Clearance can be accomplished by felbamate traversing the arachnoid granulations, the head and neck lymphatic system, the lumbar CSF, and potentially traversing the blood brain barrier with or without the transport being affected by pglycoprotein which can facilitate drug extravasation. Furthermore, the size of the molecule administered in this fashion needs to take into account the extracellular space and ideally is less than 35 nanometers.

[0126] In various embodiments, the concentration of felbamate in one or more locations in the brain (such as the cortex, temporal lobe, or any other location associated with epilepsy) is about or greater than any of 2-fold, 5-fold, 10-fold, 20-fold, 50-fold, 75-fold, 100-fold, 200- fold, 300-fold, or more than the concentration of felbamate in the plasma and/or CSF. In some embodiments, the concentration of felbamate in the CSF is the same or approximately the same as the target felbamate concentration in the brain (such as about 15 to about 60 micrograms of felbamate per gram of brain tissue).

[0127] In some embodiments, the amount of felbamate in the brain at steady state is related to the relative steady concentration of felbamate in the CSF. Felbamate in the CSF is also a function of the amount administered from the ventricular catheter and the clearance from the brain. Dog CSF is cleared five times per day, which is about twice as frequent as humans. Based on bulk CSF flow alone, the clearance in dogs is twice as fast as in humans. Another difference between dogs and humans is that dogs are rapid metabolizers in the liver, which increases the amount of felbamate cleared and eliminated from the body. This metabolism impacts serum concentrations of felbamate, thereby affecting minimal constant blood level of felbamate, which may be about 2, 3, 4, or 5 times lower in dogs than in humans. In some embodiments, the clearance rate of felbamate in humans is estimated to be about 2, 3, 4, or 5- fold less than the clearance rate in dogs.

[0128] It is appreciated that the unit content of active ingredients contained in an individual dose of each dosage form need not in itself constitute an effective amount since the necessary effective amount could be reached by the combined effect of a plurality of administrations. The selection of the amount of felbamate to include in a pharmaceutical composition depends upon the dosage form utilized, the condition being treated, and the particular purpose to be achieved according to the determination of the ordinarily skilled artisan in the field.

[0129] In accordance with certain aspects of the invention, pharmaceutical compositions are designed to maximize solubility and stability in the CSF and under conditions of use for chronic administration to the CSF. In this regard, it has been found in accordance with the present invention that the maximum aqueous solubility for felbamate in some embodiments is close to its effective concentration. For example, in certain embodiments, the concentration of felbamate in the formulation is increased five-fold over the aqueous solubility limit in order to achieve therapeutic concentrations in rat ventricles.

Exemplary Model Systems for Testing Dosing Regimens

[0130] For felbamate, the effective amount can be estimated initially either in cell culture assays or in animal models, such as rat, mouse, or dog models (such as those described herein). An animal model may also be used to determine the appropriate concentration range and routes of administration. Such information can then be used to determine useful doses and routes for administration in humans.

[0131] In certain embodiments, other types of model systems (such as the animal models described herein) may be utilized to determine the efficacy, stability, toxicity and other pharmacologic or pharmacokinetic properties of felbamate administered ICV. Exemplary models of epilepsy include the acute PTZ model, carotid ligation, and Kainate. As described further below, using an acute PTZ model demonstrated alteration of the seizure threshold. Epilepsy may be modeled using generalized seizure models with DBA/2 mice, genetically epilepsy prone rats or gerbils, maximal electroshock models, simple parietal seizure models such as with microapplication of convulsant drugs, penicillin, picrotoxin, bicuculin, strychnine, or kainic acid. Chronic seizure models such as application of alumina hydroxide, cobalt, tungsten, or zinc can be used. An exemplary complex parietal seizure model involves injecting tetanus toxin into the hippocampus.

[0132] In certain embodiments to evaluate depression and anxiety there are animal models including elevated plus, open maze, and water tank models. We demonstrated that alteration of time in the elevated plus open arm and open maze showed efficacy for felbamate. Such behavioral paradigms can demonstrate decreased anxiety by increased entry into the open arms of the elevated plus maze, and increased activity in the central areas of the open field maze (Mechiel Korte and De Boer, 2003; Crawley, 1985). Both the open field and elevated plus mazes can demonstrate increased generalized activity levels by showing increased distances traveled over a give time period, or sedation by decreased distances traveled. The swim tank can show decreased behavioral despair (interpreted to represent depression) by increased struggling to escape the water (Russig et al, 2003).

[0133] Model systems for anxiety include fear-potentiated startle reflex, conflicts test (food in open field, or Vogel punished drinking), an elevated plus maze, social interaction, or approach/avoidance paradigm. Depression may be modeled with Porsolt (forced) swim, tail suspension, olfactory bulbectomized rats, Flinders Sensitive Line rates, Fawn Hooded rats, learned helplessness, or maternal separation. Anhedonia may be modeled using novelty object place conditioning.

Kits

[0134] Also provided are kits for ICV administration of the pharmaceutical compositions and formulations described herein {e.g., compositions with between about 1 mg to about 250 mg of felbamate (such as about 1 mg to about 180 mg) and a cyclodextrin, a PEG or DMSO).

[0135] In certain embodiments, the kits may include a desired amount of at least one pharmaceutical formulation as disclosed herein. Kits may further comprise suitable packaging and/or instructions for use of the formulation. Kits may also comprise a means for the delivery of the formulation, for example, for delivery to the receptacle of a pump. Kits may also comprise a receptacle of the pump that contains the formulation in the appropriate amount and concentration. Other devices that are used as part of a system for ICV administration are known to those of skill in the art, and these may be included as part of a kit. [0136] The kits may include other agents for use in conjunction with felbamate. These other agent(s) may be provided in a separate form, or mixed with felbamate, provided such mixing does not reduce the effectiveness of felbamate or formulations described herein. In some embodiments, the second therapy is compatible with ICV administration. In some embodiments, the second therapy is formulated for delivery by a route of administration other than ICV administration.

[0137] The kits may include appropriate instructions for preparation and administration of the formulation, side-effects of the formulation, and any other relevant information. The instructions may be in any suitable format, including, but not limited to, printed matter, videotape, computer readable disk, or optical disk.

[0138] In another aspect of the invention, kits for treating an individual who suffers from the conditions described herein are provided, comprising a first container comprising the appropriate dosage amount of a formulation described herein, and instructions for us. The container may be any of those known in the art and appropriate for storage and delivery of the formulations. In certain embodiments, the kit further comprises a second container comprising a pharmaceutically acceptable carrier, diluent, adjuvant, etc. for preparation of the composition to be administered to the individual.

[0139] Kits may also be provided that contain sufficient dosages of the formulations as disclosed herein to provide effective treatment for an individual for an extended period, such as about any of 1-3 days, 1-5 days, a week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, 8 weeks, 3 months, 4 months, 5 months, 6 months, 7 months, 8 months, 9 months, or more.

[0140] Kits may also include multiple doses of the formulations and instructions for use and packaged in quantities sufficient for storage and use in pharmacies, for example, hospital pharmacies and compounding pharmacies.

[0141] To assist in understanding the present invention, the following Examples are included. The experiments described herein should not, of course, be construed as specifically limiting the invention and such variations of the invention, now known or later developed, which would be within the purview of one skilled in the art are considered to fall within the scope of the invention as described herein and hereinafter claimed. EXAMPLES

[0142] The present invention is described in more detail with reference to the following non-limiting examples, which are offered to more fully illustrate the invention, but are not to be construed as limiting the scope thereof.

Example 1. Exemplary Felbamate Composition and its Stability

[0143] The felbamate and cyclodextrin formulation listed in Table 2 A below was tested to measure its stability. Stability testing showed a lack of degradation of felbamate in glass vials at two months. Exemplary criteria for such formulations are listed in Table 2B.

Table 2A: Exemplary Formulation

Table 2B: Exemplary Criteria for Formulations

"NMT" denotes "not more than."

[0144] In some embodiments, felbamate is packaged in a 40 mL USP Type 3 glass vial with an appropriate stopper/closure. In some embodiments, the formulation does not contain a preservative. In some embodiments, the target pH of the final reconstituted dosing solution is between about 7.3 and about 7.5. In some embodiments, the components used in the manufacture of the formulation include HPBCD, WFI, and sodium hydroxide for pH adjustments. The commercial source of HPBCD is parenteral grade CDEX.

[0145] Felbamate is insoluble at neutral pH, requiring either organic solvents or a low pH in order to be solubilized (Merck Index, 2004). Because it is desirable to formulate drugs at physiological pH (-7.4), and because degradation accelerates under acidic conditions (Hasan et ah, 2002, Yaksh 1999), HPBCD was used to solubilize felbamate at pH 7.4. Felbamate was formulated with increasing mole ratios of HPBCD (0-4). Since precipitation causes felbamate to form insoluble particulates, light scattering (absorbance at 500 nm in a Hitachi UV/VIS spectrophotometer; model U-2001) was used to monitor the loss of solubility as the formulation is alkalinized. After each addition of NaOH, the pH was determined and the solution was transferred to a quartz cuvette to quantify felbamate precipitation via light scattering. All formulations used subsequently were filter sterilized (0.22 μm) prior to ICV administration. [0146] A non-GLP 12 month stability assessment was conducted on the felbamate formulation. Samples were tested in glass vials. Only felbamate concentrations were assayed. The maintenance of felbamate stability is shown in Figures 1OA and Table 3.

Table 3: Felbamate Concentrations in Felbamate and Hydroxypropl- β-cyclodextrin Formulation at 37 ⁰C up to 12 Months

Felbamate Stability with Pump Solutions

[0147] The stability of felbamate in a ready-to-use solution was studied for use as a pump injection mixture inside the human body in the future. The admixtures of felbamate and hydroxypropyl-β-cylodextrin (HPBCD) in water solution were prepared in triplicate with the pH adjusted to 7.4 under 6 different storage modes and kept in a 37 °C incubator to mimic the human body environment. Samples were removed at various time points over a one-year storage period. The stability (the concentration of felbamate in mixture) was determined using the stability-indicating HPLC assay described below after suitable dilution in water.

[0148] If desired, any of the felbamate compositions described herein can be tested with a pump system (such as the Synchromed II pump system) for stability, compatibility leachables, extractables, degradation products, and adsorptivity at body temperature, room temperature, and at zero degrees at the reservoir site and the tip of the catheter using the MS LC techniques described herein.

Methods for Assaying Stability

[0149] HPLC methods were established for assaying stability. Assay accuracy and precision results are reproduced in Figure 1OB. [0150] Felbamate calibration curves were constructed at concentration ranges of 50-500 ug/mL. A standard stock solution (5 mg/mL) of felbamate was prepared in methanol. The working standard solutions of felbamate for calibration standards (50, 100, 200, 300, 400, and 500 ug/mL) were prepared by a series of dilutions. The precision and accuracy of assays were validated by establishing the intra-assay and inter-assay coefficients of variation.

[0151] Waters Empower 2 was used to collect and analyze the data obtained from UPLC^® (Waters). Samples were kept at 6 ⁰C in the autosampler. Separations were done by the ACQUITY UPLC^® BEH Cl 8, 1.7 μm, 2.1 x 50 mm column at 25 ⁰C. Mobile phase consisted of 10 mM ammonium acetate (adjusted to pH8.5) with ammonium hydroxide - acetonitrile (9: 1, VAA at time 0). A linear AB gradient is carried out with 8.57 % increase /minute of acetonitrile. Flow rate is set up to 0.5 mL/min with 2 μL injection volume. All the spectra were collected at 254 nm.

[0152] If desired, felbamate formulations can be tested for sterility and endotoxin annually for samples stored at various storage conditions (such as at about 25, 40, or 60 ⁰C). At various time points (such as at about 1, 3, 6, 9, 12, 18, 24, and/or 36 months), felbamate formulations can be tested for potency and related substances (such as using the HPLC assay described herein), pH, particulates, and/or appearance.

Example 2. ICV Felbamate Efficacy Study in a Rat Animal Model

[0153] The goal of this study was to determine the dose level of ICV felbamate required for anti-epileptic efficacy in an established preclinical model. The dose of ICV administered felbamate required to achieve an increase in the seizure threshold in Sprague Dawley rats was determined by acute administration of reformulated felbamate using the NIH recommended PTZ suppression test in a non-GLP setting. The dose of 17 mM (3.8 ug/mL, for a total dose of 0.019 ug) was determined with 5 uL injected directly ICV and tested using the acute PTZ suppression model (Figure 11).

[0154] Briefly, following insertion of a tail vein catheter, anesthetized adult male Sprague Dawley rats were injected ICV with 5 uL of formulated felbamate along with 5 other medications reformulated for this route of administration. A microinfusion cannula was placed into the right lateral ventricle and the drug of choice was infused over a 10 minute period using an uL syringe pump. [0155] At the end of the 10 minute infusion period, the cannula was removed, the incision was closed with surgical clips, and the rats were awakened. Animals were placed in a restraint (Harvard Apparatus, a box to allow maximal movement while facilitating the catheter to remain in place) and allowed to recover for 10 minutes. All rats were ambulatory at the start of the experiment. Ten minutes following ICV surgery, pentylenetetrazol (PTZ, 10 mg/ml in saline) was injected through the tail- vein catheter at a constant rate of infusion (1 mL/min, Razel syringe pump) until a motor seizure was induced. PTZ seizures were identified as myoclonic jerking followed by clonus and tonus. The time from initial application of PTZ to the first clonic seizure {i.e., forelimb clonus) was measured and defined as "latency to seizure onset." The total amount of PTZ infused was calculated and then divided by each rat's body weight to obtain the dose (mg/kg) of PTZ. This process has been characterized as a "threshold dose" (Pollack and Shen, 1985). Immediately after seizure induction, rats were euthanized with 100 mg/kg of sodium pentobarbital.

[0156] As illustrated in Figure 1 1, ICV administration of felbamate delayed the onset of seizures in this animal model. In particular, ICV felbamate significantly increased the latency to PTZ-induced seizure onset compared to control. The mean time to seizure onset was increased by 46.5% from 1.29 minutes in controls to 1.89 minutes (p=0.02) in ICV felbamate treated animals, which is approximately a 50% increase in latency to first seizure compared to controls.

Example 3. Pharmacokinetic and Biodistribution Study of Felbamate via Continuous Intracerebroventricular Administration in Beagle Dogs

[0157] The goal of this study was to obtain plasma and CSF samples at pre-determined intervals during continuous intracerebroventricular (C-ICV) seven day dosing in beagle dogs to develop a pharmacokinetic profile for felbamate.

Summary of Dog Study

[0158] Although felbamate levels required to achieve efficacy are not yet known, one study using surgical samples from 8 refractory epilepsy patients has shown that oral doses of 3600 mg/day were associated with felbamate concentrations ranging from 13 μg - 74 μg/gram in varied brain regions. Although these data do not provide evidence that these concentrations are required for efficacy, they infer a reasonable target range to assist in design of studies for development of an ICV felbamate formulation. These data have been considered together with other preclinical findings in the design of an ICV felbamate formulation that produces therapeutic efficacy at the same time as reducing substantially the levels of systemic exposure, and hence produces a significant reduction in therapy-limiting side effects.

[0159] As summarized below, this study in two dogs showed that very low ICV doses, representing 5000-fold less than human oral doses, can achieve brain levels in brain punch samples, approaching low μg levels of felbamate in select regions of the brain. Important to the design of an ICV formulation, plasma felbamate levels associated with these brain levels were very low, in the nanogram concentration range. The differential between CSF levels and the plasma was also notable, with much higher felbamate levels in the CSF than in plasma. In addition, as this first study used doses at the low end of the dose-titration curve, it is reasonably expected that in subsequent dosing studies, that higher μg/gram felbamate brain concentrations can be achieved while at the same time maintaining very low plasma felbamate levels and systemic exposure.

[0160] Felbamate was administered to two dogs at doses corresponding to 15,000- (0.24 mg/day) and 5000-fold less (0.72 mg/day), respectively, than the recommended human oral dose of 3600 mg. Felbamate at 0.72 mg/day dose achieved a maximum brain felbamate concentration of 1.34 μg/gram brain in the lateral ventricle as described below. Importantly, felbamate was detected in all brain samples studied, with levels in other areas ranging from 12.3 - 194 μg/g. Felbamate at lower doses of 0.24 mg day achieved correspondingly lower felbamate brain levels, with a maximum concentration in the 4^th lateral ventricle of 0.282 μg/g, 0.162 μg/g in the hippocampus, 0.073 μg/g in the fourth ventricle, and 0.0656 μg/g in the caudate/putamen. Significant CSF levels of felbamate were achieved up to 8 days of dosing, and appeared to have achieved a steady state level. Plasma levels of felbamate were considerably less than CSF levels, indicating the potential for a low level of systemic felbamate exposure with ICV dosing. Plasma drug levels were approximately 6 - 17 fold lower than CSF levels by day 8 of continuous dosing.

Design of Dog Study

[0161] The felbamate dosing regimen for this dog study was determined as follows. The ratio of brain to plasma felbamate concentration (Drug Concentrations in Human Brain Tissue Samples from Epileptic Patients Treated with Felbamate, Drug Metabolism and Distribution VoI 22, No.1) was found to be a mean of 66 + 26% in humans. Doses across species (rat, dog, and human) produce equivalent C_max concentrations (Felbamate Pharmacokinetics in Rat, Rabbit and Dog, Drag Metabolism and Distribution VoI 19, No.6.) in dose ranges from 11 to 100 mg/kg. Considering the rat brain/plasma data is consistent (Distribution of the anticonvulsant felbamate to CSF and brain tissue of adult and neonatal rats. Drug Metabol Dispo. 21 : 1079-1085 (1993)) with the human brain/plasma data it may be inferred the dog brain data may be consistent. A human dose of 25 mg/kg should produce a plasma C_max of approximately 30 ug/ml and brain concentrations of 19.9 ug/g. After consideration of data from a 28 day mouse ICV study, brain concentrations in the cortex averaged 214 ng/ml. Plasma levels were below the limits of quantitation in this study. Based on this data, the dose level in a study in beagle dogs was lowered several fold as the single day dose was provided over a one week period.

[0162] This study complied with all applicable sections of the current version of the Final Rules of the Animal Welfare Act Regulations (9 CFR), and the Guide for the Care and Use of Laboratory Animals, Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council, 1996. Animals that experience severe, chronic pain, or distress that cannot be relieved are painlessly euthanized. In this study, the dogs were not euthanized for pain, but were euthanized at the end of the study. Table 4 lists characteristics of the dogs used as this model system.

Table 4: Dog Model System

Genus Cams

Species Familiaris

Common Name Beagle

Sex 2 Females

0 Males

Age 1-2 years

Weight 8 - 15 kg

Source of Animals Covance Research Products

[0163] The beagle dog was chosen as the test system because of its established usefulness and acceptance as a model for toxicological and pharmacological studies in a large animal species. All animals on this study were naϊve with respect to prior treatment. [0164] Each test animal was assigned a unique nine (9) digit test animal/study number within the population making up the study. This number appeared on the cage card visible on each cage. The cage card contained the study number, treatment group, dose, and tattoo. If desired, the animals may be implanted with a transponder microchip programmed with the nine-digit animal number. The unique test animal number and/or tattoo identified raw data records and specimens.

[0165] All animals were quarantined for at least one week at Northern Biomedical Research with daily observations prior to study initiation. A fecal floatation examination for parasites was performed. The animals were vaccinated for distemper, rabies, hepatitis, leptospirosis, parainfluenza, and parvo virus.

[0166] The animals were housed individually in stainless steel cages. The housing was in compliance with the Guide for the Care and Use of Laboratory Animals, DHHS, (NIH) No. 86-23, and the Animal Welfare Act (9 CFR 3). Non-contact absorbable wood chips were used to line the pans underneath the animal's cage. Room temperatures were maintained at 72° ± 4°F. The relative humidity during the study was maintained at 50% ± 30%. The air- handling unit was set to provide 10 room air changes per hour. Lighting was automatically controlled providing 12 hours of light and 12 hours of darkness. The light-dark cycle was interrupted as required to maintain the health of the animal (e.g., observations of a moribund animal). These lighting changes were documented. Temperature, humidity, and lighting was monitored and recorded daily.

[0167] Purina Certified Lab Canine Diet #5007, approximately 400 grams, was supplied daily. Food was withheld at least 12 hours prior to general anesthesia (e.g. , surgery or spinal taps). In some instances, food may not be withheld 12 hours due to the animal needing its food because it will be undergoing repair surgeries and/or the condition of the animal warrants not withholding food. Filtered municipal water (City of Muskegon) was supplied ad libitum via an automatic watering system. Food (PMI Nutrition International, Richmond, IN) and water (Hackley Hospital and Trace Analytical Laboratories, Inc., Muskegon, MI) analyses were recorded. No contaminants were expected in the food and water in sufficient quantities to affect the conduct or results of the study.

[0168] The test article (felbamate) and vehicle were maintained at 20-37°C. Storage temperatures were monitored and recorded daily. Vials of the test articles that were opened were not used for dose solution formulation on subsequent days. Table 5 lists exemplary concentrations of felbamate. In this study, 0.2 mg/ml and 0.6 mg/ml felbamate concentrations were used.

Table 5: Felbamate Concentrations

[0169] The long-term tested stability of the test article is 12 months. Standard laboratory safety procedures were employed for handling the test and control articles. Specifically, gloves, facemask, and eye protection were worn while preparing and administering doses.

[0170] Two female beagle dogs were surgically implanted with two polyurethane catheters each; one catheter had the tip located in a lateral cerebroventricle (ICV) and the other catheter tip was located in the cisterna magna (CM). The ICV catheter was utilized for test article delivery and the CM catheter was utilized for CSF sampling. Each catheter terminated in a subcutaneous titanium access port. After a recovery period of at least 5 days, a continuous infusion (Phase 1) of 0.2 mg/ml of the test article at a rate of 50 μL/hour was delivered for 7 days in two beagle dogs. This resulted in a total daily felbamate dose of 0.24 mg. As reference, this dose level is 15,000 times less than the therapeutic dose in humans (3600 mg/day), and 3800 times less the oral dose level in dogs (100 mg/kg, or approximately 900 mg/day) that produces plasma levels approximating those in humans at therapeutic levels (50 ug/mL).

[0171] Blood (~1 ml) and CSF (0.1 ml) were sampled predose and at 1 , 2, 4, 6, 8, 24, 48, 72, 96, 120, 144, and 168 hours. After the pumps were turned off, blood (~1 ml) and CSF (0.1 ml) were sampled at 1, 2, 4, 6, 8, and 24 hour in one low dose dog (0.24 mg/day dose level). [0172] A second infusion (Phase 2) at a dose of 0.6 mg/ml of the test article at a rate of 50 μL/hour, for a daily dose of 0.72 mg/day, for 7 days began after Phase 1 (infusion and recovery) was completed in one of the two dogs. The animal was infused by C-ICV for 7 full days. Terminal blood and CSF samples were collected. Blood (~1 ml) and CSF (0.1 ml) were sampled predose, and during 1, 2, 4, 6, 8, 24, 48, 72, 96, 120, 144, and 168 hours of the continuous infusion of ICV felbamate. For reference, this dose level is 5000-fold less than human oral dose required for therapeutic efficacy (3600 mg/day). Immediately following completion of dosing on day 8 of the study, both the low dose 0.24 mg/day and the high dose 0.72 mg/day dogs were whole body perfused with saline, and the brains were harvested fresh sliced in 3 mm coronal sections and frozen.

[0173] Body weights, clinical observations, and food consumption were monitored. Neurological and physical examinations were conducted. Body weights were recorded on all animals prior to surgery, on the day of surgery, weekly during the study, and at necropsy. Additional body weights were taken to ascertain the health of the animal. Food consumption was collected daily beginning prior to surgery and continuing throughout the treatment period. The animals were observed at least twice daily for morbidity and mortality beginning on the first day of dosing. One of the morbidity and mortality checks may be done concurrently with clinical observations. Clinical signs were recorded at least once daily post surgery throughout the study period. The animals were observed for signs of clinical effects, illness, and/or death. Additional observations may be recorded based upon the condition of the animal.

[0174] For catheter implantation, the animals were pretreated with atropine sulfate as a subcutaneous injection at a dose of 0.04 mg/kg. Approximately 15 minutes later, an IV dose of 15 mg/kg of thiopental Na was provided to induce anesthesia. Each animal was masked to a surgical plane of anesthesia (if needed), intubated, and maintained on approximately 1 liter/minute of oxygen and approximately 2.0% halothane or isoflurane. The anesthetic gases and mixtures may be varied as required by the animal. Prednisolone sodium succinate IV, 30 mg/kg, and flunixin meglumine IM₅ 2 mg/kg, was administered prior to surgery. One 0.9 mm OD and 0.5 mm ID polyurethane catheter was inserted ICV and another catheter was implanted CM. The catheters terminated in a subcutaneous titanium access port. The skin was closed with sutures and tissue adhesive. [0175] Upon recovery from anesthesia, the animal was provided butorphanol tartrate IM, 0.05 mg/kg, for analgesia and placed on post-surgical antibiotic ceftiofur sodium IM, 5.0 mg/kg, BID (one injection during or prior to surgery followed by three injections). A jacket was placed on the animal post surgery.

[0176] Physical and neurological examinations were conducted prior to surgery. Additional exams may be conducted if desired. The neurological examination assessed the following:

• General Sensory and Motor Functions: level of consciousness, righting reflex, placing reflex, and wheelbarrow

• Cerebral Reflexes: pupillary reflex, orbicularis oculi reflex, and corneal reflex

• Spinal Reflexes: flexor withdrawal, extensor postural thrust, knee jerk, cutaneous reflex, and proprioception

[0177] Physical examination parameters included heart rate, respiration, temperature, auscultation (respiratory and cardiovascular), gait, disposition, abdominal palpation, lymph nodes, and general appearance of the eyes, ears, oral cavity (teeth and mucosa), skin, and nails.

[0178] MRI scans were performed prior to surgery for determination of lateral ventricle target coordinates. The sequences was a pilot, T-I , Contrast T-I, Fast Spin Echo (FSE) T-2 coronal, and T-2 sagittal and axial at a thickness of 3 mm with 0.5 mm gap. Gadolinium [0.1 mmol/kg, 0.2 ml/kg, IV] was injected into a peripheral vein immediately prior to the contrast sequence. The scans were acquired in a custom built acrylic head holder placed in a knee coil. The coil was loaded to increase the signal to noise. Additional scans/sequences may be performed if desired. Documentation of the scans was recorded in the raw data.

[0179] Blood samples (~1 ml) were collected from a peripheral vein for felbamate analysis prior to dosing and at 1, 2, 4, 6, 8, 24, 48, 72, 96, 120, 144, and 168 hours. After the pumps were turned off, blood (~1 ml) was sampled in one low dose dog only at 1, 2, 4, 6, 8, and 24 hours post-infusion. Phase 2 samples, in the high dose dog, were collected at 1, 2, 4, 6, 8, 24, 48, 72, 96, 120, 144, and 168 hours during infusion. The samples were collected in potassium EDTA, and the times were recorded. The tubes were maintained on ice packs, and then centrifuged at approximately 2400 rpm at ~4°C/room temperature for 15 minutes. The plasma was harvested, split (duplicates), placed in labeled vials, frozen in liquid nitrogen, and stored at -60°C or below until shipment on dry ice.

[0180] CSF samples (0.1 ml) were collected via the CM catheter predose and at 1, 2, 4, 6, 8, 24, 48, 96, 120, 144, and 168 hours during infusion. After the pump was turned off, CSF (0.1 ml) was sampled in one low dose dog at 1, 2, 4, 6, 8, and 24 hours post-infusion. Phase 2 samples were collected at I₅ 2, 4, 6, 8, 24, 48, 72, 96, 120, 144, and 168 hours. The animals were spinal tapped prior to necropsy.

[0181] Any animal(s) determined moribund during the study period may be sacrificed (such as with the approval of a veterinarian). Animals deemed too ill to proceed with the study may be removed from the study and treated as determined to be appropriate. Samples (e.g., clinical pathology) may be obtained from the animal to determine the condition of the animal prior to sacrifice and/or treatment.

[0182] A gross necropsy may be performed on any animal found dead or sacrificed moribund, and at the scheduled necropsy, following at least 7 days of treatment (Phase 2). AU animals were sedated with 16.0 mg/kg of thiopental sodium IV, maintained on a halothane or isoflurane/oxygen mixture, and provided with an intravenous bolus of heparin Na, 200 IU/kg. The animals were perfused with saline via the left cardiac ventricle. Animals found dead are necropsied but not perfused. In this study, no animals were found dead.

[0183] Gross lesions were noted and saved in 10% neutral buffered formalin. The brains of all animals were removed as quickly as possible after perfusion and placed in a chilled brain matrix. The fresh brains were sectioned at a thickness of 3 mm in the coronal plane to generate -17 sections per brain. Each brain slice was immediately frozen. The spinal cord was removed, and 3 sections were saved frozen from the cervical, thoracic, and lumbar areas.

[0184] The tissues that were saved included brain, dorsal root ganglia, gross lesions, and spinal cord samples. Table 6: Summary of Data that was Collected

Data

• Gross Necropsy • Physical Exam

• Body Weight Data Data Data

• Protocol, Protocol

• • Amendments and

Deviations

• Plasma and CSF

• Clinical Sign Data • Test Article

Analysis

• Concentrations of

• Dose

• Neurological felbamate in brain Administration

T Data slice and brain

JjΛa_O+ia_O punch samples

• Dosing Solution • • Surgical Data

Analysis

• Test Article Storage

Conditions,

• • Certificates of

Analysis and

Stability

• Food Consumption

Data

[0185] Data from the analysis of felbamate in canine brain, cerebrospinal fluid (CSF), and plasma is summarized below. Table 7 summarizes the two analytical methods used to measure felbamate levels.

Table 7: Summary of Analytical Methods to Measure Felbamate Levels

Analytical method 1 LC/MS/MS (Thermo Electron TSQ Quantum Access)

HPLC Conditions:

Mobile Phase A: 10 mM ammonium formate in water

B: 10 mM ammonium formate in methanol

Gradient: 0.0 - 2.0 min isocratic @ 5%B, 2.0 - 3.0 min linear gradient 5 - 95%B, 3 - 7 min isocratic @ 95%B,

10 min re-equilibration @ 5%B

Flow Rate 0.300 - 0.400 mL/min

Injection Volume 10 μL

Injection Frequency 17 min

Column: Phenomenex Luna C-18(2), 50 x 2.00 mm, 5 micron with guard column

MS Conditions:

Ionization Atmospheric Pressure Chemical Ionization (APCI)

Polarity Positive Analytical method 1 LC/MS/MS (Thermo Electron TSQ Quantum Access)

Data Type Centroid

Scan Type Selected Reaction Monitoring (SRM)

Felbamate M[NH₄J⁺ m/z = 256.2 =j> 177.8 (-10.0V)

Reserpine MH⁺ m/z = 609.3 =5- 195.1 (-35. OV)

Width 1.00

Scan Time 0.06 sec per transition

Analytical method 2 I LC/MS/MS (Thermo Electron TSQ Quantum Access)

HPLC Conditions:

Mobile Phase A: 10 mM ammonium formate in water

B: 10 mM ammonium formate in methanol

Gradient: 0.0 - 1.0 min isocratic @ 5%B, 1.0 - 2.0 min linear gradient 5 - 95%B, 2 - 6 min isocratic @ 95%B,

5 min re-equilibration @ 5%B

Flow Rate 0.300 niL/min

Injection Volume 10 μL

Injection Frequency 11 min

Column: Phenomenex Luna C- 18(2), 50 x 2.00 mm, 5 micron with guard column

MS Conditions:

Ionization Electrospray Ionization (ESI)

Polarity Positive

Data Type Centroid

Scan Type Selected Reaction Monitoring (SRM)

Felbamate MH⁺ m/z = 238.9 => 117.1 (-15.0V)

Reserpine MH⁺ m/z = 609.3 => 195.1 (-15. OV)

Width 1.00

Scan Time 0.25 sec per transition

Sample Preparation: Precipitate 50 μL of unknown brain/CSF/plasma sample or standard solution with 50 μL aliquot of 50% methanol and 100 μL of acetonitrile containing internal standard. Centrifuge at 14,000 rpm at 4⁰C for 10 min.

Transfer supernatant to autosampler vial.

Study not regulated by GLP

[0186] Brain slices and punches were weighed to the nearest 0.01 mg and a 0.9% NaCl solution was added (3:1 weightvolume). The slice or punch samples were then homogenized while in an ice bath using a Tissuemizer (Techmar) tissue grinder. Homogenized samples were centrifuged at 3750 rpm @ 4 ⁰C to separate the solids from the liquid and an aliquot (50 μL) of the liquid supernatant was sampled for LC-MS-MS analysis. Standard curve samples (standards) were prepared in normal brain homogenate processed using the above procedure (Figures 1 and 2). [0187] Table 8 and Figure 3 summarize the calibration of felbamate in the canine brain. Table 9 and Figure 4-6 summarize quality controls.

Table 8: Calibration of Felbamate in Canine Brain (Analytical Method 1)

Exact Mass = 238.0954 (monitored at m/z = 256.2 => 177.8 (-10.0V))

Cone. Area Calculated %

(ng/mL) Ratio Cone. (ng/mL) Dev.

0.510 3.49E-05 0.488 -4.24

1.02 7.54E-05 1.05 3.37

2.55 1.74E-04 2.43 -4.57

5.10 3.45E-04 4.82 -5.40

10.2 7.99E-04 11.2 9.65

25.5 1.68E-03 23.6 -7.64

51.0 3.67E-03 51.4 0.696

102 7.29E-03 102 -0.0346

255 1.76E-02 247 -3.17

510 3.25E-02 455 -10.8

765 5.54E-02 775 1.29

1020 7.68E-02 1070 ^■ 4.90

LLOQ = 0.510 ng/mL

From Thermo Electron Excalibur ver. 2.0, TSQ Quantum Access: Linear regression, 1/x weighting, force through origin y = 7.15e °⁵x, r ² = 0.9965

Table 9: Felbamate Quality Controls in Canine Brain (Analytical Method 1)

Exact Mass = 238.0954 (monitored at m/z = 256.2 => 177.8 (-10.0V))

Cone. Area Calculated %

(ng/mL) Ratio Cone. (ng/mL) Dev.

5.00 3.89E-04 5.44 8.80

5.00 3.33E-04 4.66 -6.85

5.00 3.36E-04 4.70 -5.89

5.00 3.91 E-04 5.47 9.49

50.0 3.28E-03 45.9 -8.19

50.0 3.86E-03 54.0 8.10

50.0 3.57E-03 49.9 -0.0937

50.0 3.56E-03 49.8 -0.396

200 1.53E-02 214 6.81

200 1.61 E-02 226 12.9

200 1.54E-02 215 7.49

200 1.56 E-02 219 9.36

[0188] Tables 10-13 summarize calculated concentrations of felbamate found in canine brain slice and punch samples. Table 10: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Brain Slice Samples

Animal Brain Slice Area Calculated

ID Sample # Ratio Cone, (ng/g)

00 IA-CYMAWJ #1 2.19E-04 12.3

00 IA-CYMAWJ #2 1.56E-04 8.72

00 IA-CYMAWJ #3 1.92E-04 10.8

00 IA-CYMAWJ #4 4.56E-04 25.6

00 IA-CYMAWJ #5 1.60E-03 89.2

00 IA-CYMAWJ #6 1.83E-03 102

00 IA-CYMAWJ #7 2.69E-03 150

00 IA-CYMAWJ #8 3.80E-03 213

001A-CYMAWJ #9 2.98E-03 167

00 IA-CYMAWJ #10 2.88E-03 161

001A-CYMAWJ #11 2.78E-03 156

001A-CYMAWJ #12 3.51 E-03 196

OOIA-CYMAWJ #13 2.52E-03 141

00 IA-CYMAWJ #14 5.38E-04 30.1

OOIA-CYMAWJ #15 7.65E-04 42.8

OOIA-CYMAWJ #16 4.43E-04 24.8

OOIA-CYMAWJ #17 2.80E-04 15.7

OOIA-CYMAWJ Cervical Cord 6.82E-04 38.2

OOIA-CYMAWJ Thoracic Cord 3.34E-04 18.7

OOIA-CYMAWJ Lumbar Cord 2.59E-04 14.5

Table 11: Calculated Concentrations of Felbamate found in OOIA-CYMAWJ Brain Punch Samples

Animal Brain Punch Area Calculated

ID Sample # Ratio Cone, (ng/g)

OOIA-CYMAWJ 1 (Superior Frontal) 2.16E-04 12.3

OOIA-CYMAWJ 2 (Medial Frontal) 2.55E-04 14.5

OOIA-CYMAWJ 3 (Inferior Frontal) 2.11 E-04 12.0

OOIA-CYMAWJ 4 (Lat. Ventricle series) 2.35E-02 1340

OOIA-CYMAWJ 5 (Lat. Ventricle series) 1.12E-03 64.0

OOIA-CYMAWJ 6 (Lat. Ventricle series) 7.99E-04 45.6

OOIA-CYMAWJ 7 (Lat. Ventricle series) 9.54E-04 54.4

OOIA-CYMAWJ 9 (Middle Temporal) 3.44E-04 19.6

OOIA-CYMAWJ 10 (Inferior Temporal) _*

OOIA-CYMAWJ 11 (Caudate/Putamen) - _*

OOIA-CYMAWJ 12 (Thalamic) 3.06E-03 174

OOIA-CYMAWJ 13 (Hippocampus) 1.09E-02 620

OOIA-CYMAWJ 14 (Parietal) 4.20E-04 24.0

OOIA-CYMAWJ 15 (0ccipatal) 2.25E-04 12.8

OOIA-CYMAWJ 16 (Cerebellum) 3.38E-04 19.3

OOIA-CYMAWJ 17 (Brain Stem) 9.19E-04 52.4

OOIA-CYMAWJ 18 (Aquaduct) 3.40E-03 194

OOIA-CYMAWJ 19 (Third Ventricle) 4.44E-03 253

OOIA-CYMAWJ 20 (Floor Fourth Vent.) 3.75E-03 214

OOIA-CYMAWJ 21 (Cervical Cord) 8.43E-04 48.0

OOIA-CYMAWJ 22 (Thoracic Cord) 5.10E-04 29.1

OOIA-CYMAWJ 23 (Lumbar Cord) 3.70E-04 21.1

A — = Samples could not be analyzed due to error in sample preparation Table 12: Calculated Concentrations of Felbamate found in 002-4698843 Brain Slice Samples

Animal Brain Slice Area Calculated

ID Sample # Ratio Cone, (ng/g)

002-4698843 #1 8.75E-05 4.88

002-4698843 #2 8.16E-05 4.56

002-4698843 #3 9.01 E-05 5.04

002-4698843 #4 2.81 E-04 15.7

002-4698843 #5 3.72E-04 20.8

002-4698843 #6 5.63E-04 31.5

002-4698843 #7 5.64E-04 31.6

002-4698843 #8 5.67E-04 31.7

002-4698843 #9 6.94E-04 38.8

002-4698843 #10 5.70E-04 31.9

002-4698843 #11 3.92E-04 22.0

002-4698843 #12 4.41 E-04 24.7

002-4698843 #13 3.11 E-04 17.4

002-4698843 #14 1.73E-04 9.68

002-4698843 #15 2.93E-04 16.4

002-4698843 #16 1.92E-04 10.7

002-4698843 #17 1.77E-04 9.92

002-4698843 Cervical Cord 2.21 E-04 12.4

002-4698843 Thoracic Cord 1.32E-04 7.40

002-4698843 Lumbar Cord 9.11 E-05 5.08

Table 13: Calculated Concentrations of Felbamate found in 002-4698843 Brain Punch Samples

Animal Brain Punch Area Calculated

ID Sample # Ratio Cone, (ng/g)

002-4698843 1 (Superior Frontal) 8.45E-05 4.72

002-4698843 2 (Medial Frontal) 8.91 E-05 5.00

002-4698843 3 (Inferior Frontal) 7.99E-05 4.48

002-4698843 4 (Lat. Ventricle series) 5.04E-03 282

002-4698843 5 (Lat. Ventricle series) 3.28E-04 18.4

002-4698843 6 (Lat. Ventricle series) 9.60E-05 5.36

002-4698843 7 (Lat. Ventricle series) 9.84E-05 5.52

002-4698843 9 (Middle Temporal) 1.02E-04 5.68

002-4698843 10 (Inferior Temporal) 1.42E-04 7.96

002-4698843 11 (Caudate/Putamen) 1.18E-03 65.6

002-4698843 12 (Thalamic) 1.45E-04 8.12

002-4698843 13 (Hippocampus) 2.90E-03 162

002-4698843 14 (Parietal) 9.98E-05 5.60

002-4698843 15 (Occipatal) 8.99E-05 5.04

002-4698843 16 (Cerebellum) 7.16E-05 4.00

002-4698843 17 (Brain Stem) 2.32E-04 13.0

002-4698843 18 (Aquaduct) 1.02E-03 57.2

002-4698843 19 (Third Ventricle) 3.47E-04 19.4

002-4698843 20 (Floor Fourth Vent.) 1.30E-03 72.8

002-4698843 21 (Cervical Cord) 2.11 E-04 11.8

002-4698843 22 (Thoracic Cord) 1.33E-04 7.44

002-4698843 23 (Lumbar Cord) 1.16E-04 6.48 [0189] Table 14 and Figure 7 summarize the calibration of felbamate in canine plasma (calibration curve A).

Table 14: Calibration A on Felbamate in Canine Plasma (Analytical Method 1)

Exact Mass = 238.0954 (monitored at m/z = 256.2 => 177.8 (-10.0V))

Cone. Area Calculated %

(ng/mL) Ratio Cone. (ng/mL) Dev.

0.510 3.96E-05 0.466 -8.61

1.02 7.81 E-05 0.921 -9.72

5.10 4.19E-04 4.94 -3.18

10.2 8.30E-04 9.78 -4.12

25.5 1.96E-03 23.1 -9.44

51.0 4.22E-03 49.8 -2.42

102 8.94E-03 105 3.32

255 2.15E-02 253 -0.673

510 4.29E-02 505 -0.947

765 6.37E-02 750 -1.94

1020 8.85E-02 1040 1.96

LLOQ = 0.510 ng/mL

From Thermo Electron Excalibur ver. 2.0, TSQ Quantum Access: Linear regression, 1/x weighting, force through origin, y = 8.49e-°⁵x, r ² = 0.9995

[0190] Table 15 and Figure 8 summarize the calibration of felbamate in canine plasma (calibration curve B).

Table 15: Calibration B on Felbamate in Canine Plasma (Analytical Method 1)

Exact Mass = 238.0954 (monitored at m/z = 256.2 => 177.8 (-10.0V))

Cone. Area Calculated %

(ng/mL) Ratio Cone. (ng/mL) Dev.

0.510 3.79E-05 0.538 5.45

1.02 7.95E-05 1.13 10.6

2.55 1.70E-04 2.41 -5.50

5.10 3.55E-04 5.04 -1.27

10.2 6.46E-04 9.17 -10.1

25.5 1.75E-03 24.8 -2.63

51.0 3.45E-03 49.0 -3.97

102 7.11 E-03 101 -1.16

255 1.63E-02 231 -9.58

510 3.59E-02 509 -0.203

765 5.60E-02 794 3.78

1020 6.98E-02 990 -2.91

3060 2.26E-01 3200 4.58

5100 3.75E-01 5320 4.31

10200 6.96E-01 9880 -3.14

LLOQ = 0.510 ng/mL From Thermo Electron Excalibur ver. 2.0, TSQ Quantum Access: Linear regression, 1/x weighting, force through origin, y = 7.05e^"05x, r ² = 0.9986

[0191] Table 16 and Figure 9 summarize the calibration of felbamate in canine plasma (calibration curve C).

Table 16: Calibration C on Felbamate in Canine Plasma (Analytical Method 2)

Exact Mass = 238.0954 (monitored at m/z = 256.2 => 177.8 (-10.0V))

Cone. Area Calculated %

(ng/mL) Ratio Cone. (ng/mL) Dev.

5.11 2.80E-04 5.11 0.146

9.75 4.85E-04 9.75 -4.43

28.3 1.33E-03 28.3 10.9

50.5 2.40E-03 50.5 -0.90

247 1.45E-02 247 -3.07

533 4.06E-02 533 4.61

687 5.87E-02 687 -10.2

1069

1.16E-01 1069 4.77

LLOQ = 5.11 ng/mL

From Thermo Electron Excalibur ver. 2.0, TSQ Quantum Access: Quadratic regression, 1/x² weighting, y = 5.73e^"0s + 4.3Se ⁰⁵X + 6.14e^"°V, r ²= 0.9902

[0192] Tables 17 and 18 summarize calculated concentrations of felbamate found in canine plasma samples. Calculated concentrations of felbamate presented in Tables 17 and 18 were derived from the regression obtained for plasma calibration A (Table 14 and Figure 7).

Table 17: Calculated Concentrations of Felbamate found in 001 A-CYMA WJ Plasma Samples (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ Plasma (Pump On) Predose, Day-1 - < LLOQ

00 IA-CYMAWJ Plasma (Pump On) 1-Hr, Day-1 1.69E-04 2.39

001A-CYMAWJ Plasma (Pump On) 2-Hr, Day-1 1.57E-04 2.23

001A-CYMAWJ Plasma (Pump On) 4-Hr, Day-1 1.06E-04 1.50

001A-CYMAWJ Plasma (Pump On) 6-Hr, Day-1 1.76E-04 2.49

00 IA-CYMAWJ Plasma (Pump On) 8-Hr, Day-1 6.79E-05 0.963

00 IA-CYMAWJ Plasma (Pump On) 24-Hr, Day-2 2.26E-04 3.21

00 IA-CYMAWJ Plasma (Pump On) 48-Hr, Day-3 2.89E-04 4.09

00 IA-CYMAWJ Plasma (Pump On) 72-Hr, Day-4 2.89E-04 4.10

00 IA-CYMAWJ Plasma (Pump On) 96-Hr, Day-5 3.28E-04 4.65

001A-CYMAWJ Plasma (Pump On) 120-Hr, Day-6 3.34E-04 4.74

001A-CYMAWJ Plasma (Pump On) 144-Hr, Day-7 3.06E-04 4.34

001A-CYMAWJ Plasma (Pump On) 168-Hr, Day-8 2.81 E-04 3.99 Table 18: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Plasma Samples Post Infusion (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ Plasma (Pump Off) 1-Hr, Day-8 2.36E-04 3.34

00 IA-CYMAWJ Plasma (Pump Off) 2-Hr, Day-8 2.29E-04 3.25

00 IA-CYMAWJ Plasma (Pump Off) 4-Hr, Day-8 1.59E-04 2.26

00 IA-CYMAWJ Plasma (Pump Off) 6-Hr, Day-8 1.01 E-04 1.44

00 IA-CYMAWJ Plasma (Pump Off) 8-Hr, Day-8 1.97E-04 2.79

00 IA-CYMAWJ Plasma (Pump Off) 24-Hr, Day-9 7.46E-05 1.06

[0193] Tables 19 and 20 summarize calculated concentrations of felbamate found in canine plasma samples. Calculated concentrations of felbamate presented in Tables 19 and 20 were derived from the regression obtained for plasma calibration B (Table 15 and Figure 8).

Table 19: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Plasma Samples Post Infusion (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ Plasma (Pump Off) 48-Hr, Day-10 - < LLOQ

00 IA-CYMAWJ Plasma (Pump Off) 72-Hr, Day-1 1 - < LLOQ

00 IA-CYMAWJ Plasma (Pump Off) 96-Hr, Day-12 - < LLOQ

00 IA-CYMAWJ Plasma (Pump Off) 124-Hr, Day-13 - < LLOQ

00 IA-CYMAWJ Plasma (Pump Off) 144Hr, Day-14 - < LLOQ

00 IA-CYMAWJ Plasma (Pump Off) 168-Hr, Day-15 - < LLOQ

Table 20: Calculated Concentrations of Felbamate found in 001A-CYMAWJ plasma samples (dose level 0.6 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ Plasma (Pump On) 1 -Hr, Day-15 - < LLOQ

00 IA-CYMAWJ Plasma (Pump On) 2-Hr, Day-15 - < LLOQ

00 IA-CYMAWJ Plasma (Pump On) 4-Hr, Day-15 3.63E-05 0.428*

00 IA-CYMAWJ Plasma (Pump On) 6-Hr, Day-15 2.10E-04 2.48

00 IA-CYMAWJ Plasma (Pump On) 8-Hr, Day-15 2.84E-04 3.34

001A-CYMAWJ Plasma (Pump On) 24-Hr, Day-16 9.47E-04 11.2

001A-CYMAWJ Plasma (Pump On) 48-Hr, Day-17 1.41 E-03 16.6

001A-CYMAWJ Plasma (Pump On) 72-Hr, Day-18 1.42E-03 16.7

00 IA-CYMAWJ Plasma (Pump On) 96-Hr, Day-19 1.34E-03 15.8 00 IA-CYMAWJ Plasma (Pump On) 120-Hr, Day-20 1.48E-03 17.5 00 IA-CYMAWJ Plasma (Pump On) 144-Hr, Day-21 1.24E-03 14.6 00 IA-CYMAWJ Plasma (Pump On) 168-Hr, Day-22 1.30E-03 15.3

* = calculated concentration below LLOQ

[0194] Table 21 summarizes calculated concentrations of felbamate found in canine plasma samples. Calculated concentrations of felbamate presented in Table 21 were derived from the regression obtained for plasma calibration C (Table 16 and Figure 9).

Table 21: Calculated Concentrations of Felbamate found in 002-4698843 Plasma Samples (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

002-4698843 Plasma (Pump On) Predose, Day-1 - < LLOQ

002-4698843 Plasma (Pump On) 1-Hr, Day-1 1.23E-04 1.51*

002-4698843 Plasma (Pump On) 2-Hr, Day-1 1.83E-04 2.90*

002-4698843 Plasma (Pump On) 4-Hr, Day-1 7.69E-05 0.453*

002-4698843 Plasma (Pump On) 6-Hr, Day-1 1.51 E-04 2.17*

002-4698843 Plasma (Pump On) 8-Hr, Day-1 1.10E-04 1.22*

002-4698843 Plasma (Pump On) 24-Hr, Day-2 2.51 E-04 4.44*

002-4698843 Plasma (Pump On) 48-Hr, Day-3 2.02E-04 3.33*

002-4698843 Plasma (Pump On) 72-Hr, Day-4 2.58E-04 4.60*

002-4698843 Plasma (Pump On) 96-Hr, Day-5 5.36E-04 10.9

002-4698843 Plasma (Pump On) 120-Hr, Day-6 5.22E-04 10.6

002-4698843 Plasma (Pump On) 144-Hr, Day-7 1.45 E-04 2.02*

002-4698843 Plasma (Pump On) 168-Hr, Day-8 4.20E-04 8.28

* = calculated concentration below LLOQ

[0195] Tables 22 and 23 summarize calculated concentrations of felbamate found in canine cerebrospinal fluid (CSF) samples. Calculated concentrations of felbamate presented in Tables 22 and 23 were derived from the regression obtained for plasma calibration A (Table 14 and Figure 7).

Table 22: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Cerebrospinal Fluid Samples (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

001A-CYMAWJ CSF (Pump On) Predose, Day-1 - < LLOQ

001A-CYMAWJ CSF (Pump On) 1-Hr, Day-1 7.06E-03 100

00 IA-CYMAWJ CSF (Pump On) 2-Hr, Day-1 2.48E-03 35.2

00 IA-CYMAWJ CSF (Pump On) 4-Hr, Day-1 1.12E-03 15.9

00 IA-CYMAWJ CSF (Pump On) 6-Hr, Day-1 1.55E-03 22.1

00 IA-CYMAWJ CSF (Pump On) 8-Hr, Day-1 1.62E-03 23.0

00 IA-CYMAWJ CSF (Pump On) 24-Hr, Day-2 3.21 E-03 45.5

001A-CYMAWJ CSF (Pump On) 48-Hr, Day-3 3.83E-03 54.3 00 IA-CYMAWJ CSF (Pump On) 72-Hr, Day-4 3.80E-03 53.9

00 IA-CYMAWJ CSF (Pump On) 96-Hr, Day-5 4.01 E-03 56.9

00 IA-CYMAWJ CSF (Pump On) 120-Hr, Day-6 5.09E-03 72.2

00 IA-CYMAWJ CSF (Pump On) 144-Hr, Day-7 3.18E-03 45.1

001A-CYMAWJ CSF (Pump On) 168-Hr, Day-8 4.11 E-03 58.3

Table 23: Calculated Concentrations of Felbamate found in 001 A-CYMA WJ Cerebrospinal Fluid Samples post infusion (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ CSF (Pump Off) 1-Hr, Day-8 2.08E-03 29.5

00 IA-CYMAWJ CSF (Pump Off) 2-Hr, Day-8 1.05E-03 14.9

00 IA-CYMAWJ CSF (Pump Off) 4-Hr, Day-8 2.94E-04 4.16

00 IA-CYMAWJ CSF (Pump Off) 6-Hr, Day-8 1.92E-04 2.72

00 IA-CYMAWJ CSF (Pump Off) 8-Hr, Day-8 1.58E-04 2.23

00 IA-CYMAWJ CSF (Pump Off) 24-Hr, Day-9 1.07E-04 1.52

[0196] Tables 24 and 25 summarize calculated concentrations of felbamate found in canine CSF samples. Calculated concentrations of felbamate presented in Tables 24 and 25 were derived from the regression obtained for plasma calibration B (Table 15 and Figure 6).

Table 24: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Cerebrospinal Fluid Samples post infusion (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

00 IA-CYMAWJ CSF (Pump Off) 48-Hr, Day-10 - < LLOQ

00 IA-CYMAWJ CSF (Pump Off) 72-Hr, Day-1 1 - < LLOQ

00 IA-CYMAWJ CSF (Pump Off) 96-Hr, Day-12 - < LLOQ

00 IA-CYMAWJ CSF (Pump Off) 124-Hr, Day-13 - < LLOQ

00 IA-CYMAWJ CSF (Pump Off) 144Hr, Day-14 - < LLOQ

00 IA-CYMAWJ CSF (Pump Off) 168-Hr, Day-15 - < LLOQ

Table 25: Calculated Concentrations of Felbamate found in 001 A-CYMAWJ Cerebrospinal Fluid Samples (dose level 0.6 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

001A-CYMAWJ CSF (Pump On) 1-Hr, Day-15 4.02E-04 4.74

001A-CYMAWJ CSF (Pump On) 2-Hr, Day-15 3.43E-04 4.04

001A-CYMAWJ CSF (Pump On) 4-Hr, Day-15 1.18E-03 13.9

001A-CYMAWJ CSF (Pump On) 6-Hr, Day-15 3.20E-03 37.7

00 IA-CYMAWJ CSF (Pump On) 8-Hr, Day-15 1.94E-03 22.9

001A-CYMAWJ CSF (Pump On) 24-Hr, Day-16 2.73E-03 32.2

00 IA-CYMAWJ CSF (Pump On) 48-Hr, Day-17 3.85E-03 45.4

00 IA-CYMAWJ CSF (Pump On) 72-Hr, Day-18 6.06E-03 71.4

00 IA-CYMAWJ CSF (Pump On) 96-Hr, Day-19 7.77E-03 91.6

00 IA-CYMAWJ CSF (Pump On) 120-Hr, Day-20 8.55E-03 101

00 IA-CYMAWJ CSF (Pump On) 168-Hr, Day-22 7.84E-03 92.4 [0197] Tables 26 summarizes calculated concentrations of felbamate found in canine CSF samples. Calculated concentrations of felbamate presented in Table 26 were derived from the regression obtained for plasma calibration C (Table 16 and Figure 9). No cerebrospinal samples were provided for the 72, 96 and 120 hour time points.

Table 26: Calculated Concentrations of Felbamate found in 002-4698843 Cerebrospinal Fluid Samples (dose level 0.2 mg/mL)

Animal Sample Sample Area Calculated

ID Type Time Ratio Cone. (ng/mL)

002-4698843 CSF (Pump On) Predose, Day-1 - < LLOQ

002-4698843 CSF (Pump On) 1-Hr, Day-1 1.10E-02 193

002-4698843 CSF (Pump On) 2-Hr, Day-1 3.96E-03 79.2

002-4698843 CSF (Pump On) 4-Hr, Day-1 1.72E-03 35.7

002-4698843 CSF (Pump On) 6-Hr, Day-1 2.84E-03 58.1

002-4698843 CSF (Pump On) 8-Hr, Day-1 2.57E-03 52.8

002-4698843 CSF (Pump On) 24-Hr, Day-2 6.69E-03 127

002-4698843 CSF (Pump On) 48-Hr, Day-3 7.63E-03 142

002-4698843 CSF (Pump On) 168-Hr, Day-8 2.22E-02 337

[0198] As shown in Figures 12A and 12B, the CSF concentration increased between days 3 and 8 suggesting attainment of steady state. During this time, a consistent level of felbamate was detected in the serum. A second dog study is nearing completion with a 3 -fold higher ICV felbamate dose (0.6 mg/mL concentration of felbamate). The low levels of felbamate in the plasma and CSF indicates that only a relatively small amount of felbamate is cleared from the canine brain. This low clearance rate of felbamate from the brain indicates that ICV administration of felbamate can be used to achieve therapeutically effective concentrations of felbamate in the brain and low concentrations outside of the brain (such as in locations that may be responsible for adverse side-effects of felbamate).

[0199] Table 27 summarizes the concentration of felbamate in the canine CSF, plasma, and brain for two different doses of felbamate.

Table 27: Concentration of Felbamate in the canine CSF, plasma, and brain.

* preceding 48 hour CSF value (apparent steady state) used due to incorrect sampling procedure at 168 hour;

* * second animal dosed, CSF/plasma data only

[0200] If desired, other formulations of felbamate can be tested in dogs as described herein. If desired, the location of the drug delivery catheter can be optimized (such as lateral ventricle versus 3^rd ventricle). Catheter-tubing interaction studies may be performed to assess whether the formulation adheres to the tubing. Metabolites of felbamate can be measured. In some embodiments, dosing titration is performed by dosing up to a maximum level of tolerability and then back down. Alternatively, dosing up to 6 mg/day, 18 mg/day, and/or 50 mg/day may be performed.

[0201] If desired, a neuropharmacokinetic assessment using radiolabeled felbamate and/or neural imaging studies may also be performed.

Example 4. ICV Administered Felbamate in a 28-Day Toxicology Study in a Rat Animal Model

[0202] The toxicology of ICV administered felbamate was tested in a rat animal model. Specifically, male Sprague Dawley rats (250-300 g, Harlan Sprague Dawley, San Diego, CA) were implanted with Alzet osmotic minipumps connected to brain infusion cannula (Alzet, Cupertino, CA) aimed at the lateral anterior ventricle. The pumps delivered vehicle, formulated felbamate 1.73mM, and formulated felbamate 17.3 mM in HPBCD at a rate of 0.25 ml/hr for 28 days. The rats were permitted to recover for 7 days prior to behavioral testing. On the 7^th day, one half of the rats in each group were tested in the elevated plus maze, while the other half were tested in the open field. One week later (day 14 after pump implantation) the groups were reversed. Elevated maze plus and open field testing have been described elsewhere (Overstreet et al., 2003). Briefly, the study consisted of placing a rat in the center region of a black plexiglass + shaped platform with 13 cm wide arms. Two of the arms were enclosed by 32 cm high walls while the remaining 2 arms were open. The maze was elevated 51 cm off the floor. The movements of the rat were computer tracked for the 5 minutes of the paradigm and the percent time spent in each type of arm and distance traveled in each arm (open, closed, or in the center square) computer analyzed (Limelight 2, Actimetrics, Wilmette, IL). Open field has also been described elsewhere (Overstreet et al, 2003). The open field consisted of a 104 X 104 cm square of black plexiglass with 39 cm high walls. A rat was placed near one side wall of the field and allowed to explore at will for 5 minutes during which its activity was computer monitored (Limelight 2, Actimetrics, Wilmette, IL). The field was divided into 3 regions (3 concentric squares), the outer region (adjacent to the walls), a middle region, and the center square. The percent time and distance traveled in each region were analyzed.

[0203] ICV administered felbamate produced an increase in the distance traveled in both arms of the elevated plus maze and a similar, though non-significant increase in distance traveled in the open field, indicating no sedation (Figures 13A- 13H). There is a dose- dependent decrease in the time spent in the closed arm of the elevated plus which corresponds to the increase in time spent in the open arm. This indicated a reduction in anxiety for the doses tested. Also there was no noted activation (the opposite of sedation and a central side-effect of oral felbamate) in the elevated plus or open field testing above.

[0204] The quiescent time in the Porsolt Forced Swim test (FST) of behavioral despair (depression) was also measured. Briefly, a 20 cm diameter, 56 cm tall acrylic cylinder was filled with about 45 cm of water (35 ⁰C), and a rat was placed in the water for 5 minutes and behavior was monitored. The amount of time spent quiescent (non-struggling) was compared between animals receiving the drug and those receiving saline controls. A reduction in quiescent time is thought to reflect a reduction in behavioral despair. The doses of felbamate tested did not alter the quiescent time in the Porsolt FST (Figure 14) suggesting that this drug does not have antidepressant effects in this test system.

[0205] In the same animals and at the same doses, there was no noted increase in ataxia (Figure 15). In particular, the rats were also assessed for ataxia, which is a measure of altered gate and ability to change body position. They were placed on their backs and time to "righting" was measured.

[0206] In the same animals and at the same doses, there was no noted increase in sedation (Figure 15). Also there was no noted activation (the opposite of sedation), in the elevated plus or open field testing as noted above (Figures 13 A- 13 H). Felbamate also did not appear to alter the rate of weight gain compared to vehicle controls (Figures 16A and 16B). The effect of felbamate on standard blood analysis in rats is shown in Figure 17. [0207] If desired, higher doses of felbamate can also be tested in this rat model to achieve the target of 15-60 micrograms per gram of brain tissue.

Example 5. Tissue Distribution of ICV Administered Felbamate in a Rat Animal Model

[0208] The tissue distribution of felbamate following ICV administration of felbamate to rats was also measured using standard methods. Briefly, a group of Sprague Dawley rats were implanted with a ventricular cannula attached to an osmotic minipump containing tritiated felbamate in the excipient. Various concentrations (as indicted in Figures 18 A-24B) of felbamate were administered at a rate of 50 μL/hour over 8 days. There were five rats given a felbamate concentration of 17.3mM, and three rats given a felbamate concentration of 51.9 mM. After 8 days, the rats were sacrificed under anesthesia, the brain and various tissues were dissected out, frozen, and sectioned. Sections were apposed to tritium sensitive film; the film was exposed and developed.

[0209] The brain (Figures 18A- 18C), CSF (Figures 19A and 19B), plasma (Figures 2OA and 20B), bone marrow (Figure 21), heart (Figures 22A and 22B), kidney (Figures 23 A and 23B), and liver (Figures 24A and 24B) were analyzed using standard methods to determine the concentration of felbamate present (using essentially the same methods as described in Example 3 above for dogs). Figures 18A-24B list the measured concentration of felbamate, the theoretical concentration of felbamate, and the accuracy of the measured concentration of felbamate.

Example 6. Exemplary Rat and Dog Studies

[0210] If desired, any of the pharmaceutical compositions described herein can be tested in additional animal studies, such as the rat or dog studies described below. For example, toxicology studies with ICV administered felbamate for a 3-month duration can be conducted in rats and dogs. These studies may be preceded by dose range-finding studies in order to select proper dosage levels. The 3 -month studies include recovery groups with a duration of recovery of 1 month to assess the reversibility or persistence of any potential treatment effects. Rats and dogs are selected as the nonclinical test species because these species have been utilized in previous oral toxicology studies with felbamate. [0211] The rat studies employ Alzet mini pumps for the delivery of reformulated felbamate and vehicle. The pumps are refilled/replaced every 4 weeks. In dogs, the same pump to be utilized in the clinical trial are implanted and used for the delivery of reformulated felbamate.

[0212] Analytical testing is conducted to characterize the stability of the test formulations in both the Alzet and Medtronic pumps. Periodic testing is conducted during the course of the toxicology studies to verify the concentration of the dosing formulation both prior to and after placement in the delivery apparatus.

[0213] The definitive animal GLP studies are conducted using formulated material representative of that which is utilized in proposed clinical trials. The high doses employed in the definitive toxicology studies is either a maximum feasible dose based upon formulation and/or dose volume considerations or approximates a maximum tolerated dose (MTD).

[0214] As part of the GLP toxicology studies, plasma and CSF samples are collected in the rat and dog in order to characterize the toxicokinetics of felbamate and HPBCD. Brain samples are also analyzed for the parent felbamate compound in the 90-day dog study. Brain samples are from multiple cortical areas of the brain in both hemispheres. In addition, CSF and plasma samples are obtained at different times of dosing. All analyses are performed under GLP conditions with a validated assay. The definitive studies include comprehensive clinical endpoints, including a Functional Observational Battery (FOB) in rats and histopathology evaluations of a full list of tissues which include head-only perfusion fixation and employment of special stains in the brain.

(i) Rat 14-Day Continuous infusion. Repeated ICV Dose Toxicity Study

[0215] The objective of this non-GLP study is to assess further the continuous infusion dose toxicity and tolerability of ICV felbamate in rats. Three dose groups of reformulated felbamate or a vehicle control is administered continuously into the lateral ventricles for 14 days. The study design and a brief outline of the study are provided below (Table 28). Table 28: Study Design for 14-Day Continuous Infusion ICV Dose Study of ICV Felbamate in Rats

Clinical observations: Twice daily

Body weights: Recorded pre-study and approximately weekly thereafter

Food consumption: Recorded weekly

Clinical pathology: At time of sacrifice (main and recovery animals)

Necropsy: Includes an examination of the external features of the carcass

Histopathology: Brain

Toxicokinetics: CSF and brain samples are collected from satellite groups of animals in the low, mid, and high dose groups on Days 1 and 14. Sampling includes 3 rat/sex/timepoint. Samples are analyzed using a validated method for felbamate and CDEX. (Ii) Rat 90-Day Continuous Infusion ICV Dose Toxicity Study with a 28-Day Recovery Period

[0216] The objective of this GLP study is to assess the continuous dose toxicity and toxicokinetics of reformulated felbamate in rats. Reformulated felbamate is administered continuously ICV for 90 days to three dose groups; a vehicle and saline control group are also included. Dose solution analyses are conducted at various time points throughout the study to confirm the concentration and/or homogeneity of the dosing solutions. The study design and a brief outline of the study are provided below (Table 29).

Table 29: Study Design for a 90-Day Continuous Infusion ICV Dose Study of ICV Felbamate in Rats

* An additional 9/sex/group in each of the felbamate treatment groups is included for plasma toxicokinetic analyses.

Clinical observations: Twice daily

Body weights: Recorded pre-study and approximately weekly thereafter

Food consumption: Recorded weekly Ophthalmology: All animals are subjected to an ophthalmo logical examination by a qualified veterinarian prior to initiation and near the end of the dosing and recovery phases.

Functional Observation Battery: Study

Clinical pathology (Hematology,CHnical Chemistry, Coagulation Factors, and Urinalysis):

On study Day 91 (main animals) and Day 119 (recovery animals)

Necropsy: The day following the last dose (Day 91), 20 rat/sex/group are euthanized and perfusion fixation performed. Gross abnormalities are documented. The remaining rats (up to 5 rats/sex/group in the control and high-dose groups) are allowed a 28-day recovery period and are similarly sacrificed on Day 119.

Organ weights: Tissues to be weighed include adrenals, brain, epididymides, heart, kidneys, liver, lungs, ovaries, spleen, thyroid/parathyroid, testes, and uterus.

Histopathology: A standard list of tissues are collected, and preserved. Tissues from control and high-dose animals are processed, and evaluated microscopically from all animals. The brain and spinal cord are systematically sectioned and special stains employed (anti-GFAP and Fluoro Jade-B) to facilitate the identification of any subtle neuropathological changes.

Toxicokinetics: Serial blood and CSF samples are collected from satellite groups of animals in the low, mid, and high dose groups on Days 1 and 90. Samples are analyzed for parent drug using a validated method. The brain are also analyzed for parent drag and CYDEX following the final blood collection. (iii) Dog 90-Day Continuous infusion ICV Dose Toxicity Study with a 28-Day Recovery Period

[0217] The objective of this GLP study is to assess the continuous infusion dose toxicity and toxicokinetics of reformulated felbamate in dogs. Reformulated felbamate are administered continuously ICV for 90 days to three dose groups; a vehicle and saline control group are also included. Dose solution analyses are conducted at various time-points throughout the study to confirm the concentration and/or homogeneity of the dosing solutions. The study design and a brief outline of the study are provided below (Table 30).

Table 30: Study Design for a 90-Day Continuous Infusion ICV Dose Study of ICV felbamate in Dogs

Clinical observations: Twice daily

Body weights: Recorded pre-study and approximately weekly thereafter

Food consumption: Recorded weekly

Ophthalmology: All animals are subjected to an ophthalmological examination by a qualified veterinarian prior to initiation and near the end of the dosing and recovery phases.

Neurological examination: Prior to treatment and weeks 4, 8, 12, and 16. Clinical pathology (Hematology, Clinical Chemistry, Coagulation Factors, and Urinalysis):

Prior to treatment and weeks 4, 8, and 12 and 16.

Necropsy: The day following the last dose (Day 91), 4 dogs/sex/group are euthanized and perfusion fixation performed. Gross abnormalities are documented. The remaining dogs (up to 2 animals/sex/group in the control and high-dose groups) are allowed a 28-day recovery period and are similarly sacrificed on Day 119.

Organ weights: Tissues to be weighed include adrenals, brain, epididymides, heart, kidneys, liver, lungs, ovaries, spleen, thyroid/parathyroid, testes, and uterus.

Histopathology: A standard list of tissues are collected, preserved, processed and examined microscopically from all animals. The brain and spinal cord are systematically sectioned and special stains employed (anti-GFAP and Fluoro Jade-B) to facilitate the identification of any subtle neuropathological changes.

Toxicokinetics: Serial blood samples are collected from groups of animals in the control low, mid, and high dose groups on Days 1, 30, 60, and 90. Samples are analyzed for parent drug and CDEX using a validated method.

Example 7. Measurement of CNS Toxicology

[0218] If desired, standard animal models can be used to measure any CNS and/or systemic toxicity from any of the pharmaceutical compositions described herein. In an exemplary method, a rat model is used. At necropsy, blood is collected via cardiac puncture and placed in Na-EDTA anticoagulant or serum-separator tubes (SST). Anticoagulant blood is used to generate complete blood counts (CBCs). SST blood is spun down and serum collected to generate biochemical profiles CSF is collected via a cisterna magna puncture.

[0219] Tissues collected at necropsy for histopathology analysis include brain, skeletal muscle, eye, liver and kidney, and are preserved in 10% neutral-buffered formalin (5:1 formalin to tissue) for a minimum of 48 hours prior to processing. Tissues are processed for routine light microscopic analysis. Briefly, tissues are dehydrated, imbedded in wax, cut into 8μm sections and mounted on slides, re-hydrated, and hematoxylin/eosin stained (H&E).

[0220] Biochemical and CBC values are pooled by treatment group and means compared to sham control group values using paired t-tests. Histopathology samples are assigned a point value based on the degree of necrosis, inflammatory cell infiltrate, and fibrosis. Scores for each are summed by group and compared to sham control tissues.

[0221] If desired, standard methods can also be used to compare the tissue distribution of felbamate following ICV administration to the distribution following IP or oral administration (systemic), hi one exemplary method, tissues from euthanized animals are collected and drug levels quantitated as follows. Tissues are recovered, place in an Eppendorf tube and weighed. Tissue solubilizer (Biolute-S, Serva Electrophoresis) is added and the mixture is allowed digesting for a minimum of twelve hours on a rocking platform. Digests are then mixed with scintillation fluid (Scinti-safe, Fisher Scientific, 50:50 v/v) and counts are quantitated utilizing a Beckman model LS 6500 scintillation counter.

[0222] Counts are normalized to initial tissue weights and drug distribution comparisons made between ICV and IP delivery routes.

Example 8. Exemplary Human Phase I/II Clinical Trial

[0223] In desired, any of the pharmaceutical compositions described herein can also be tested in humans. In some embodiments, the initial felbamate study in humans is conducted in patients with refractory epilepsy rather than healthy subjects due to both ethical and practical considerations that result from the invasive nature of the ICV delivery system and the risk profile of felbamate. During the study, patients are maintained throughout on the same dose of antiepileptic agents present at the time of enrollment. The study's primary goals are to assess subject safety and tolerance to the ICV administration of felbamate/cyclodextrin composition and to obtain human pharmacokinetic data on CSF clearance of the drug and vehicle.

[0224] A secondary goal is to obtain preliminary within subject comparisons of seizure rate parameters before exposure to study drug (felbamate) before and after pump implantation and after exposure to maximally tolerated doses (the dose at which minimal side-effects are present) of felbamate during the double-blind maintenance phase of the study. Seizure rate parameters consist of percent reduction in total seizure frequency, and the percent of subjects with reduction in seizure frequency of > 50%. It may be possible to obtain estimates of the drug's therapeutic effect, if any, from a comparison of seizure rates observed among patients in the study's 2nd and 3rd cohorts who are randomized to drug and placebo. Another secondary goal is to determine whether there is any evidence of a relationship between the level of CNS exposure to felbamate and seizure frequency. Although open, uncontrolled, and confounded by time, correlational analyses may provide insight into felbamate' s therapeutic potential as a treatment for epilepsy.

[0225] The study includes refractory epilepsy patients who have failed to respond adequately to treatment with two or more anti-epilepsy drugs (AEDs). The patients enter the study receiving the same stable regimen at the time of enrollment and maintain this throughout. They can be receiving AEDs as polytherapy and may have an active vagus nerve stimulator in place. Approximately 35 patients from up to 5 centers are recruited; it is estimated that at least 29 of the 35 complete the study.

[0226] The study employs a rising dose, 3 sequential cohort design. Treatment is administered openly to the first cohort. In the 2^nd and 3^rd cohorts, treatment assignment to drug and placebo is randomized (2:1 allocation).

[0227] The study is divided into 5 phases: i) a pretreatment baseline phase of 12 weeks, ii) an open phase of approximately 4 weeks to assess safety in 5 subjects prior to commencement of the double-phase portion of the study, iii) a double-blind phase of 12 weeks, iv) a post-treatment phase for patients who do not wish to enter the open-label extension, and v) the final, optional phase, which is an open-label extension in which eligible patients may continue to receive a known dose of the drug.

[0228] Pharmacokinetic assessment is conducted during the initial open phase of the study to assess the CSF elimination of felbamate during bolus and continuous infusion administration. Concurrent plasma concentrations of felbamate during ICV administration is also determined.

[0229] Study drug treatment in both the open-label and double-blind cohorts consists of an initial hospital dose-titration period and an out-patient maintenance period. [0230] In the first cohort, all 5 subjects receive active treatment under open label and uncontrolled conditions. During the double-blind phase of the study, both the 2ⁿ and 3^rd cohorts have 12 patients randomized and treated under blinded, controlled conditions (8 active; 4 placebo per cohort).

[0231] At a screening visit, eligible subjects are identified, and written, voluntary informed consent is obtained. Blood samples are taken for full hematologic and chemistry testing, and a seizure diary begun. At 2 follow-up visits that occur one and two months after the screening visit, patient diaries are reviewed and subject compliance assessed. Based on the information gathered, qualifying subjects are offered a chance to participate in the active treatment phases of the study.

[0232] Following admission and placement of the ICV pump delivery system, qualifying subjects in each cohort undergo titration (over a period of 20 days for cohort 1, 12 days for cohort 2, and 8 days for cohort 3) to their maximally tolerated dose. Once this dose is deemed to have been attained, subjects are discharged and treated with study drug during the double-blind phase for 3 months. To minimize the discomfort of side-effects, subjects who have experienced adverse events during the hospitalization period undergo a 10% reduction in the maximal tolerated dose prior to their discharge from the in-patient facility.

[0233] Over the ensuing 3 months, the regimen begun immediately prior to discharge is maintained if the regimen is tolerated. During this outpatient treatment phase, subjects are seen monthly at formal visits. Patients are also contacted weekly throughout the outpatient phase to assess pump functionality and adverse events. In addition, during the first week after hospital discharge, the patients are contacted daily to assess patient well-being. At the end of the 3 month outpatient treatment period, the pump is programmed to taper the felbamate dose over 10 days in all subjects. Subjects are then seen in clinic to discuss the open extension study.

[0234] Subjects deemed to have had benefited from treatment during the comparison phase of the study are offered the opportunity to enroll in an open extension study. Those subjects opting to enter the extension phase are allowed to remain on active drag as long as the drag product remains under active investigation and/or until it is approved for marketing and becomes available from ordinary commercial sources. [0235] Patients who elect to discontinue treatment are offered the choice of removing the pump or maintaining it in place and entering other studies if available.

[0236] In human adult epilepsy patients, the brain concentrations of felbamate achieved with an oral dose of 3600 mg per day is reported to range from 13 to 73 micrograms per gram of brain tissue. In the felbamate study, the target dose for human subjects is the amount estimated, based on extrapolations from large animal ICV administration models, to be required to attain a maximum concentration of 60 ug/gm of felbamate within brain tissue.

[0237] The dose required for humans relative to that required in animal ICV models is assumed be proportional to total brain weight. Thus, the predicted target ICV dose in humans is 25 fold greater than that required in beagles (beagle brain weight is 70 grams; adult human brain weight is 1700 grams). Brain drug concentrations (in dogs) are estimated from the amount of drug infused, minus the amount of drug cleared, divided by the brain weight.

Cohort 1 Cun-blinded)

[0238] The delivery device is implanted during the first day of hospitalization. The reservoir is filled and the pump set to flow at a rate that begins delivering active drug to the CSF on day 3. On day 3, the first subject receives a bolus consisting of a dose calculated from the dog study to achieve CSF levels in the range of 30 ug/gm of brain tissue. The dose is administered over one hour. For the ensuing 3 days, 12 lumbar CSF samples is obtained from a catheter, which is removed at the end of this period. Six samples are obtained the first day, 4 samples are obtained the second day, and 2 samples are obtained on the third day. Blood samples are obtained at the same time points. The samples are assayed for felbamate and cyclodextrin concentrations, as well as common laboratory parameters of toxicity and/or indices of hematologic and biochemical functions. In addition, CSF is analyzed for protein and white cell content. If the dose for the first subject is well tolerated, the next 4 subjects receive a dose calculated to give an initial brain concentration of 60 ug/gm of brain tissue. Elimination from CSF kinetics is calculated from these samples to be used for the 2^nd and 3^rd group dosing schedules.

[0239] At the end of this initial PK phase of the study, each subject begins a 20-day long dose escalation period. The starting dose is 5% of the estimated target dose and is increased by 5% each subsequent day as tolerated. Judgments concerning whether or not a subject is tolerating a given dose is based on daily clinical interviews using both a structured and open- ended assessment measures. In addition, subjects are asked to report any symptoms occurring at any time.

[0240] Dose escalation ceases when a subject has been deemed to reach his maximally tolerated dose or 100% of his predicted target dose. Those subjects who experience side- effects have the dose reduced by 10% from the minimally tolerated dose, or, if still not tolerated, decreased to a dose at which no side-effects are experienced.

Cohort 2

[0241] Based on the doses tolerated by the first 5 subjects, the next cohort of 12 subjects are entered, and treatment started at 1/3 of the average dose tolerated by the first cohort. The 12 patients are randomized (2:1 allocation) to active drug and placebo. Assuming that the cohort 2's starting dose is higher than cohort l's, a shorter titration period to attain the target dose may be considered. Thus, if all patients in cohort tolerated a 20-day titration to the predicted target dose, an up titration period of approximately 12 days is attempted. A lumbar CSF sample is obtained at the end of the titration to measure felbamate and cyclodextran concentrations, as well as safety parameters.

Cohort 3

[0242] The third cohort of 12 subjects (8 active; 4 controls) is started at 2/3 of the mean tolerated of the first cohort. A single lumbar CSF sample is obtained when the maximum dose is attained by lumbar puncture prior to discharge. This is assayed as done for the other samples.

Outpatient phase

[0243] All subjects able to tolerate continuing infusion of their assigned treatment are discharged from the inpatient facility and followed at biweekly intervals for 3 months. During this phase, patients continue to keep a seizure diary and raters remain blind to treatment assignment.

Post treatment dose-reduction phase

[0244] At the last study visit after 3 months of ICV felbamate or placebo outpatient treatment, all subjects have the delivery system programmed for a 10-day taper to the minimum delivery rate. Five days later, the subjects return to the clinic and are offered the opportunity to enroll in an open labeled active treatment study. The remaining material is removed from the reservoir, and those who wish to participate in the open study have active drug placed. The delivery system is programmed to attain 100% of their previously-tolerated dose over the next 15 days. Subjects have 24/7 access to the study personnel, and if any side- effects develop, the delivery rate is reduced by 10% or more as needed. At all times, subjects may voluntarily withdraw from the study for any reason Decisions regarding continuation is based on the concordance of the subject's and study monitor's perception of benefit, tolerability, and safety. Visits during the course of the open extension phase are every 3 months; patients are asked to maintain their seizure diaries. If the study is stopped or a patient discontinues treatment, the drug is drained from the reservoir. However, the subject may elect to keep the delivery system in place to be eligible for additional studies.

Additional Safety Monitoring

[0245] These studies are performed at neurology sites trained in Good Clinical Practice (GCP) procedures with prior experience in the implantation and use of the Medtronic delivery pump for drug delivery. The written informed consent for this study contains a through description of all warnings and precautions contained in current FDA-approved felbamate labeling with particular regard for the risks of aplastic anemia and hepatic failure. Liver function and hematologic evaluations, including platelets and reticulocytes, are performed at baseline and at intervals of monthly for the first 3 months during the study, and every 3 - 6 months during the open follow-up phase. Patients who discontinue from the study receive monitoring one month after study termination. During the out-patient phase, study subjects are advised to be alert for signs of infection, bleeding, easy bruising, or signs of anemia and are advised to report to a physician immediately if any such signs or symptoms appear. Patients are also advised to be alert for signs of liver dysfunction and to report them to the study investigator immediately if they occur. This also applies to patients who discontinue from the study.

[0246] The study procedures also follow safety measures noted in the approved labeling for the Synchromed pump. Approved labeling also includes any post-marketing updates to professionals and patients. For example, patients, caregivers and study staff are advised of the need for vigilance for the signs and symptoms of meningitis, as well as the prodromal clinical signs or symptoms of new neurological conditions or disorders. Example 9. Exemplary Human Phase I/II Clinical Trial

[0247] In desired, any of the pharmaceutical compositions described herein can also be tested in additional humans clinical trials, such as the clinical trial described below to assess the safety, pharmacokinetics, and initial efficacy of reformulated felbamate given by IVC infusions to patients with uncontrolled partial seizures.

[0248] The study includes male and female subjects, aged 18 years and older, with partial onset or complex partial seizures, with or without secondary generalization who are taking at least one AED at entry. Approximately 35 subjects at 5 sites are enrolled. The length of the study is up to 7.5 months. The study includes a three months baseline, 2-4 weeks in the hospital for implantation and dose escalation, three months of blinded treatment, and 2 weeks to taper the dose of the drug.

[0249] Key inclusion criteria are listed below.

• Inclusion criterion "a" or "b":

a. failed surgical treatment (including vagus nerve stimulation) or pre-surgical evaluation identified no surgical option

b. failed medical management of adequate dosing of at least two oral drugs of different mechanisms

• At least four complex partial or generalized tonic-clonic seizures/month, as established by a 3 -month observation period

• If female of childbearing potential, must be using an acceptable method of birth control

[0250] Key exclusion criteria are listed below.

• Patients who have previously been treated with felbamate

• Women who are pregnant or breastfeeding

• Unable to comply with all aspects of the protocol including giving informed consent • Past history of recurrent meningitis

• Acute symptomatic seizures (caused by brain tumor, acute stroke, intracranial hemorrhage, or encephalitis) or psychogenic seizures

• A history of alcohol abuse in the past two years

• A history of drug abuse; psychiatric illness such as severe, clinically significant depression (as evaluated by BDI); poor motivational capacity; or severe language disturbances, particularly of receptive nature or with serious cognitive deficits

• Evidence of clinically significant disease (cardiac, respiratory, gastrointestinal, hepatic, hematologic, or renal disease, etc.) that in the opinion of the Investigator could affect the patient's safety or trial conduct

• Increased intracranial pressure as evaluated by clinical means (presence of papilledema in eye ground exam, compressed sulci/ventricle on MRI scan)

• Previous implantation of metallic material (e.g. , vascular clips, cochlear implant) in the cranium (except in the mouth), pacemaker, implanted medication pumps, or neural stimulators. This does not apply to implantation of a vagus nerve stimulator (Cyberonics 100, 102, or 102R).

• Drug treatment acting primarily on the central nervous system (other than the regular anticonvulsant treatment and one antidepressant that lowers the seizure threshold such as antipsychotic drugs (chlorpromazine or clozapine) or tricyclic antidepressants

• Diseased or damaged skin over the face or scalp

[0251] Primary outcomes are listed below.

i) Establish preliminary safety, tolerability, and dosing ranges in patients,\ using laboratory and clinical endpoints. ii) Assess pharmacokinetic parameters of felbamate and cyclodextran behavior in CSF and blood. Study assumes hospitalization for treatment and observation with studies including MRIs, clinical assessment, blood, and CSF studies. Assumes placement of a CSF tap for measurement of CSF levels. Routine laboratory safety parameters is monitored. PK parameters are also assessed using standard methods, such as those described herein.

[0252] Secondary outcomes are listed below.

i) Preliminary estimates of seizure frequency during the double-blind phase. Estimates are based on patient diaries. Estimates include:

• reduction in total partial seizure frequency from baseline to the double- blind period.

• proportion of responders defined as 50% or more reduction in total partial seizure frequency from baseline to the double-blind period

• seizure freedom

• treatment failure

[0253] An exploratory outcome includes correlation of pharmacokinetic parameters with preliminary efficacy data obtained during the double-blind phase.

Example 10. Exemplary Human Phase III Clinical Trial

[0254] If desired, any of the methods described herein can be tested in a human phase III clinical trial to determine their ability to treat epilepsy in humans. In some embodiments, any of the methods described herein can be compared to the oral administration of felbamate. For example, the efficacy and safety of ICV administration of felbamate can be compared with an oral standard of care group as a treatment for medically refractory complex partial and/or generalized seizures. In some embodiments, a multicenter, inpatient and outpatient, randomized, double-blinded study is used. [0255] Standard methods can be used for this clinical trial. A suitable number of patients is used, such as the number of patients estimated from the Phase I/II study described above that is sufficient to achieve statistically significant end-point for greater than 50% reduction in seizures. Male and female subjects, aged 18 years and above, with partial onset or complex partial seizure disorders, with or without secondary generalization are included in the study. Patients must experience at least four seizures per month to be enrolled.

[0256] Inclusion Criteria are listed below.

• greater than 2 seizures per month.

• satisfaction of criteria (a) or (b) below.

a. failed medical management and surgical evaluation.

b. failed medical management of adequate dosing of at least two oral drugs of different mechanisms.

• If female of childbearing potential, must be using an acceptable method of birth control.

• Written informed consent.

• Age between 18 to 80 years.

• A stable anticonvulsant regimen (not more than three anticonvulsants) defined as unchanged dose or dose modifications lower than 20% in the last month (Blood levels of anticonvulsants are measured at the beginning of the study, prior, and after intervention, and after the study to assure that the type and dose of medication remains constant). For the vagus nerve stimulator, the stimulation parameters have to be unchanged for at least one month.

• One antidepressant on a stable dose regimen for at least 1 month is allowed.

• Mini-Mental-Status examination greater than 23 points.

• Commitment to participate in the long-term follow-up (up to 5 months). [0257] Exclusion Criteria are listed below.

• A history of any neurological illness other than the epilepsy.

• Acute symptomatic seizures (caused by brain tumor, acute stroke, intracranial hemorrhage, or encephalitis) or psychogenic seizures.

• A history of severe alcohol or drug abuse; psychiatric illness such as severe, clinically significant depression (as evaluated by BDI); poor motivational capacity; or severe language disturbances, particularly of receptive nature or with serious cognitive deficits.

• More than moderate uncontrolled medical problems (e.g. , cardiovascular disease, active cancer or renal disease, any kind of end-stage pulmonary or cardiovascular disease, hypo/hyperthyroidism, severe diabetes, peripheral arteriopathy, a deteriorated condition due to age, or other medical conditions as determined by the study physician that would interfere with participation in this study).

• Increased intracranial pressure as evaluated by clinical means (presence of papilledema in eye ground exam, compressed sulci/ventricle on MRI scan).

• Previous implantation of metallic material (e.g., vascular clips, cochlear implant) in the cranium (except in the mouth), pacemaker, implanted medication pumps, or neural stimulators. This does not apply to implantation of a vagus nerve stimulator (Cyberonics 100, 102, or 102R).

• Drug treatment acting primarily on the central nervous system (other than the regular anticonvulsant treatment and one antidepressant) that lowers the seizure threshold such as antipsychotic drugs (chlorpromazine or clozapine) or tricyclic antidepressants.

• Diseased or damaged skin over the face or scalp.

• Pregnancy.

• Systemic hypersensitivity to felbamate.

[0258] The primary outcome measure is the reduction in the mean seizure frequency in the active and control arms during a three-month observation period, with baseline seizure frequency established by observation. Secondary endpoints include 50 and 75% reduction in seizure frequency and seizure freedom. Control patients have an identical procedure to active patients, i.e., implantation of an ICV catheter for medication infusion, and receive vehicle infusion during the double blind study period.

[0259] Other secondary outcome measures include the scores of the neuropsychological testing (HVLT-R, BVMT-R, CTMT, and COWAT) and the number of epileptiform discharges in the EEG. Furthermore, the patients answer several questionnaires to evaluate quality of life (QOLIE-31-P), seizure severity (SSQ), and mood (BDI). To better understand the mechanisms underlying the proposed change of seizure frequency, single- and paired- pulse transcranial magnetic stimulation (TMS) is used to identify corticomotor excitability changes.

[0260] At the conclusion of the study, patients successfully completing the double blind portion of the study are offered access to an open label follow on trial in which they may continue to receive study medication.

[0261] The foregoing examples and detailed description are offered by way of illustration and not by way of limitation. All publications, patent applications, and patents cited in this specification are herein incorporated by reference as if each individual publication, patent application, or patent were specifically and individually indicated to be incorporated by reference. Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

[0262] Unless defined otherwise, the meanings of all technical and scientific terms used herein are those commonly understood by one of skill in the art to which this invention belongs. One of skill in the art will also appreciate that any methods and materials similar or equivalent to those described herein can also be used to practice or test the invention.

[0263] For use herein, unless clearly indicated otherwise, use of the terms "a", "an," and the like refers to one or more. [0264] Reference to "about" a value or parameter herein includes (and describes) embodiments that are directed to that value or parameter per se. For example, description referring to "about X" includes description of "X."

[0265] It is understood that aspect and embodiments of the invention described herein include "comprising," "consisting," and "consisting essentially of aspects and embodiments.

REFERENCES

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[0267] Blasberg RG, Patlak CS, Shapiro WR. Distribution of methotrexate in the cerebrospinal fluid and brain after intraventricular administration. Cancer Treat Rep. 1977 Jul;61(4):633-41.

[0268] Blasberg RG, Patlak C, Fenstermacher M. Intrathecal chemotherapy: brain tissue profiles after ventriculocistemal perfusion. J Pharmacol Exp Ther. 1975 Oct;195(l):73-83.

[0269] Collins JM. Pharmacokinetics of intraventricular administration. J Neurooncol. 1983;1(4):283-91.

[0270] Crawley JN. Exploratory behavior models of anxiety in mice. Neuroscience & Biobehavioral Reviews. 9(l):37-44, 1985.

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[0273] Mechiel Korte S. De Boer SF. A robust animal model of state anxiety: fear- potentiated behaviour in the elevated plus-maze. European Journal of Pharmacology. 463(1- 3): 163-75, 2003.

[0274] Overstreet DH et al. , Involvement of 5-HT1 A receptors in animal tests of anxiety and depression: evidence from genetic models. Stress. 2003 Jun;6(2): 101-10. [0275] Russig H. Pezze MA. Nanz-Bahr NI. Pryce CR. Feldon J. Murphy CA. Amphetamine withdrawal does not produce a depressive-like state in rats as measured by three behavioral tests. Behavioural Pharmacology. 14(1); 1-18, 2003.

[0276] Yaksh TL. Spinal systems and pain processing: development of novel analgesic drugs with mechanistically defined models. Trends Pharmacol Sci 1999;20:329-37.

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Claims

CLAIMSWhat is claimed as new and desired to be protected by Letters Patent of the United States is:

1. A method for treating epilepsy in a human in need thereof, the method comprising administering to the human a pharmaceutical composition comprising (i) between about 1 mg to about 250 mg of felbamate and (ii) a cyclodextrin, a polyethylene glycol (PEG), or dimethylsulfoxide (DMSO), wherein the pharmaceutical composition is administered using an ICV route of administration.

2. The method of claim 1, wherein the total daily dose of felbamate for the human is between about 1 mg to about 250 mg.

3. The method of claim 1 or 2, wherein the pharmaceutical composition is administered over at least about two months via an implantable delivery device.

4. The method of any one of claims 1 -3, wherein the human is selected from a population of humans who are refractory to treatment via systemic administration of felbamate.

5. The method of any one of claims 1-3, wherein the human is selected from a population of humans who are refractory to treatment via systemic administration of a compound for the treatment of epilepsy other than felbamate.

6. The method of claim 4 or 5, wherein the refractory human shows an alleviation or prevention of one or more symptoms when treated by ICV administration of the pharmaceutical composition.

7. The method of claim 1, wherein the pharmaceutical composition comprises (i) between about 1 mg to about 180 mg of felbamate and (ii) a cyclodextrin.

8. The method of claim 7, wherein the cyclodextrin is β-hydroxypropyl- cyclodextrin.

9. The method of claim 7, wherein the pharmaceutical composition contains between about 1 to about 30% cyclodextrin (w/w).

10. The method of claim 1, wherein the pharmaceutical composition comprises (i) between about 1 mg to about 250 mg of felbamate and (ii) a PEG.

11. The method of claim 1 , wherein the concentration of felbamate in the PEG is about 1 mg/ml to about 150 mg/ml.

12. The method of claim 1, wherein the pharmaceutical composition comprises (i) between about 1 mg to about 250 mg of felbamate and (ii) DMSO.

13. The method of claim 1 , wherein the concentration of felbamate in DMSO is about 1 mg/ml to about 450 mg/ml.

14. The method of claim 1 , wherein the felbamate maintains solubility in the pharmaceutical composition for at least about two months at physiological temperature and pH.

15. The method of claim 1 , wherein the felbamate maintains solubility in cerebral spinal fluid upon ICV administration to the human.

16. The method of claim 1 , wherein felbamate is administered to the third and/or fourth cerebral ventricle of the human.

17. The method of claim 1 , wherein felbamate is administered to one or both lateral cerebral ventricles of the human.

18. The method of claim 1 , further comprising administering felbamate by a second route of administration other than ICV administration.

19. The method of claim 1 , wherein the second route of administration is administration to the lumbar cistern and/or cisterna magna.

20. The method of claim 1 , further comprising administering a second therapy comprising another compound for the treatment of epilepsy.

21. The method of claim 20, wherein the second therapy is an anti-epilepsy agent that acts on the GABA system, a sodium channel, and/or a calcium channel.

22. The method of claim 20, wherein the second therapy is selected from the group consisting of lamictal, bumex, tegretol, valproate, adenosine, pharmaceutically acceptable salts, esters, and acids thereof, and combinations thereof.

23. The method of claim 20, wherein the second therapy is administered using an ICV route of administration.

24. The method of claim 23, wherein the second therapy is administered to the third and/or fourth cerebral ventricle of the human.

25. The method of claim 23, wherein the second therapy is administered to one or both lateral cerebral ventricles of the human.

26. The method of claim 20, wherein the second therapy is administered to the lumbar cistern and/or cisterna magna.