Abstracts

Pregabalin has anticonvulsant, analgesic, and anxiolytic effects. It is a potent ligand for the alpha[sub]2[/sub]-delta subunit of voltage-gated calcium channels. Results from clinical trials demonstrate robust efficacy for pregabalin used as add-on therapy for partial seizures. 1480 patients entered four, long-term, open-label, add-on trials, 968 from double-blind, randomized, placebo-controlled trials and 512 [italic]de novo[/italic] patients. Pregabalin, up to 600 mg/day, was taken BID or TID. Daily seizure frequency was recorded in patient diaries. At the data cut-off, 77.2% and 59.4% of patients were exposed to pregabalin for at least 24 and 52 weeks, respectively, with a maximum of 1989 days. 68.9% of pregabalin exposure was at doses of 450 mg/day or greater. Approximately 69% of patients were taking at least two other AEDs at screening. At the data cut-off, the mean number of seizure-free days per 28 days of treatment was 21.5 days, representing a mean 41.3% improvement compared with baseline. In total, 7.9% (88/1119) of patients were seizure-free over their last 6 months of pregabalin treatment, and 5.9% (52/877) were seizure-free over the last year. Across the four studies, the proportions of patients who were seizure free ranged from 7.4% to 24.2% and from 4.5% to 18.4% over the last 6 months and 1 year, respectively. Examined by quarter over the first four years of the studies, the weighted mean dose remained in the range of approximately 450-500 mg/day. At the data cut-off, 13% had discontinued the study due to adverse events. Pregabalin was well tolerated, and no new concerns were identified with long-term treatment. The proportions of patients free of seizures with long-term treatment further supports the robust and sustained efficacy of pregabalin in patients who had very poor control of seizures before initiating pregabalin treatment. (Supported by Pfizer, Inc)