A double-blind crossover study of cinromide versus placebo in epileptic outpatients with partial seizures

Cinromide was evaluated versus placebo as add-on therapy in a double-blind crossover study in epileptic outpatients with partial seizures at three sites. Four-week base lines were used before, between, and after the two 12-week treatment periods of the crossover. An operational definition was used to classify each partial seizure as Type A, B, or C. Doses of concurrent antiepileptic drugs were adjusted to maintain pretreatment therapeutic plasma levels. Doses of cinromide ranged from 1,200 to 4,800 mg/day, depending on patient response. Seven patients were withdrawn from the study because of adverse experiences (two receiving placebo and five receiving cinromide). Twenty-eight patients completed the entire 36-week study. A decrease in the average frequency of seizures/week was observed in 12 patients receiving cinromide and in 16 patients receiving placebo. The median frequencies with cinromide and placebo were 3.3 and 2.9 seizures/week, respectively (median initial base-line frequency 3.5 seizures/week for all 28 patients). Although patients were randomly assigned to receive either cinromide or placebo first, the median base-line seizure frequency was greater at the start of the first treatment period in the cinromide group (4.3 versus 2.5 seizures/week) and greater at the start of the second treatment period in the placebo group (3.8 versus 1.4). The median seizure frequency in each higher group decreased with treatment, whereas it increased in each of the lower groups. This study did not demonstrate a beneficial effect of cinromide over placebo for Type A, B, or C partial seizures. The data suggested the presence of an oscillation of seizure frequency in our population of epileptic patients having partial seizures, as well as a placebo effect. No significant carry-over effects were observed. Cinromide has previously been shown to have significant antiepileptic activity in various animal models of epilepsy. The lack of an antiepileptic response to cinromide in humans may have been due to factors other than species differences but indicates that a positive results of a drug in animal models is not the sole factor necessary to predict beneficial antiepileptic activity in humans.