Main Entry Criteria. Adults with medication-resistant partial seizures experiencing at least four seizures per 28 days

Comparator. Felbamate (3,600 mg/day given q.i.d.) versus low-dose valproate (15 mg/kg/day) as monotherapy

Number of Patients. Multicenter trial n = 95; single-center trial n = 42

Primary Outcome Variable. The number of patients in each treatment group who met the escape criteria

Results. In the multicenter trial, the percentage of patients who met the escape criteria was 40% (18/45) in the felbamate group and 78% (39/50) in the low-dose valproate group. In the single-center trial, the percentage of patients who met the escape criteria was 14% (3/21) in the felbamate group and 90% (19/21) in the low-dose valproate group. In both trials, the difference in the percentage of patients meeting the escape criteria was statistically significant (p<0.001) in favor of felbamate. These two studies by design were intended to demonstrate the effectiveness of felbamate monotherapy. The studies were not designed or intended to demonstrate comparative efficacy of the two drugs.

Main Entry Criteria. Patientswhose dosage of standard AEDs was reduced while undergoing evaluations for surgery of intractable epilepsy. All patients had confirmed partial-onset seizures with or without generalization, the seizure frequency during surgical evaluation not exceeding an average of four partial seizures per day or more than one generalized seizure per day and a minimum average of one partial or GTC seizure per day for the last 3 days of the surgical evaluation.

Comparator. Felbamate, placebo (compared in patients undergoing an inpatient presurgical evaluation)

Number of Patients. 61

Primary Outcome Variable. Time to fourth seizure after randomization to treatment with felbamate or placebo

Results. 13 (46%) of 28 patients in the felbamate group versus 29 (88%) of 33 patients in the placebo group experienced a fourth seizure. The median times to fourth seizure were >28 days in the felbamate group and 5 days in the placebo group. The difference between felbamate and placebo in time to fourth seizure was statistically significant (p = 0.002) in favor of felbamate.

Main Entry Criteria. Patients with refractory, partial-onset seizures who were receiving phenytoin and carbamazepine at therapeutic levels

Comparator. Felbamate as add-on therapy at a starting dosage of 1,400 mg/day in three divided doses, increased to 2,600 mg/day in three divided doses, and placebo

Number of Patients. 28

Primary Outcome Variable. Percentage reduction in seizure frequency

Results. Patients treated with felbamate had fewer seizures than those treated with placebo for each treatment sequence. There was a 23% (p = 0.018) difference in the percentage seizure frequency reduction in favor of felbamate.

Main Entry Criteria. Adults with four or more partial seizures per month despite concomitant therapeutic blood levels of phenytoin and carbamazepine

Comparator. Placebo versus felbamate

Number of Patients. 56

Primary Outcome Variable. Percentage reduction in seizure frequency

Results. Felbamate was statistically superior to placebo in seizure reduction, percentage seizure reduction, and truncated percentage seizure reduction.