Evidence for sustained efficacy of levetiracetam as add-on epilepsy therapy

To evaluate the long-term clinical usefulness of levetiracetam (LEV, Keppra((R))(1)) as add-on therapy in patients with refractory epilepsy.

Data for all 1422 patients with refractory epilepsy treated with LEV during the development program were analyzed for changes in seizure frequency per week, seizure freedom, and adverse events.

Median percent reduction from baseline in seizure frequency per week over the whole treatment period was 39.6%, and no decrease over time was observed within each cohort exposed to LEV for durations ranging from 6 to 54 months. The median treatment period was 399 days (range 1-8 years). The proportion of responders during the first 3 months of LEV treatment was 39.2%. This proportion remained stable at 6 months (36.1%). Overall, 38.6 and 20.1% of patients had reductions in seizure frequency of at least 50 and 75%. Sixty-five (4.6%) patients were seizure-free over their entire treatment period, compared with 167 (11.7%) and 126 (8.9%) during their last 6 and 12 months of follow-up. Ninety-seven (19.8%) of 491 patients who received only one other antiepileptic drug (AED) in addition to LEV were seizure-free during their last 6 months. The proportion of patients who reduced their number of concomitant AEDs was 14.4% (205 patients), while 5.5% (79 patients) were treated with LEV only at the end of follow-up. Accidental injury (28.0%), infection (26.6%), headache (25.8%), somnolence (23%), asthenia (22.6%), and dizziness (18.9%) were among the most common adverse events.

LEV offers sustained efficacy in patients with refractory partial seizures, and its long-term tolerability is similar to that seen in the short-term placebo-controlled trials.