Evaluation Phenobarbital as Adjunctive Therapy in Participants With Partial Onset Seizures

Primary:

-to evaluate the efficacy of once daily (OD) administration of 60 mg and 100 mg
phenobarbital, in reducing seizure frequency in participants with partial onset seizures
(Type I seizures; complex or simple with motor symptoms only) not fully controlled despite
treatment with 1 to 3 concomitant anti-epileptic drugs (AEDs) or AEDs with Vagus Nerve
Stimulator (VNS)

Secondary:

- to confirm dose response relationship of 60 and 100 mg phenobarbital doses,

- to assess the effects of phenobarbital on Type I seizures,

- to assess the safety of phenobarbital

- to assess the tolerability of phenobarbital

Inclusion Criteria:

- participants from 17 to 70 years old;

- history of Type I partial onset seizures (complex or simple with motor symptoms only);

- participants must have had electroencephalogram (EEG), magnetic resonance imaging
(MRI) or computed tomography (CT) with results consistent with diagnosis of
partial-onset seizures;

- participants having at least eight Type I partial onset seizures during 8-week
baseline period;

- participants being uncontrolled while treated by 1 to 3 permitted concomitant
anti-epileptic drug (AED) and/or Vagus Nerve Stimulation (VNS);

- participant has been on a stable dose of their current anti-epileptic treatment regime

Exclusion Criteria:

- currently taking phenobarbital or primidone;

- currently taking felbamate or vigabatrin;

- history of prior allergic reaction to phenobarbital;

- history of psychogenic seizures;

- history or presence of status epilepticus;

- history or presence of seizures occurring only in clusters;

- participant taking any drug with possible Central Nervous System (CNS) effects except
if stable from 1 month prior Visit 1;

- history of cerebrovascular accident (CVA) or transient ischemic attack (TIA);

- presence of any sign suggesting rapidly progressing brain disorder or brain tumor;

- presence of unstable arteriovenous malformations, meningiomas or other benign tumors;

- history of porphyria;

- presence of clinically significant findings on physical exam, vital signs,
electrocardiogram (ECG) or safety lab assessments, including renal or hepatic
insufficiency;

- history of alcohol or drug abuse within the year prior to screening;

- participant who is known to be non-compliant;

- participant who is male or female who refuses to use an acceptable form of
contraception;

- female who is pregnant or lactating or intends to become pregnant;

- participant who has taken part in any investigational device or product within 2
months prior to the screening visit