Long-term assessment of topiramate for epilepsy: an open-label, single-arm, multicentre, prospective study in a naturalistic setting.

Background And Objective: Most patients with epilepsy require long-term medical therapy. Newer antiepileptic drugs (AEDs) appear to be overall similarly effective to older agents but may be better tolerated. However, most of the clinical data available for newer AEDs derive from a number of short-term studies. The objective of this study was to explore long-term outcomes in patients with epilepsy treated with topiramate in routine clinical practice.

Methods: This was an open-label, multicentre, optional follow-up monotherapy study that included adolescents and adults with epilepsy who completed two similarly designed 28- or 30-week studies and agreed to participate for an additional 52 weeks. Seizure types and frequency, topiramate dose, vital signs and treatment-emergent adverse events (TEAEs) after 12, 26, 39 and 52 weeks were documented. Post hoc analyses to explore differences between males and females were conducted.

Results: 114 patients (49.0% women, mean ± SD age 43 ± 17.5 years) with a mean ± SD disease duration of 61 ± 118 months (men 54 ± 96 vs women 68 ± 138 months) were followed up for a median of 18.5 months. Seventy-eight percent of patients completed the study. Reasons for premature discontinuation were: loss to follow-up (10.5%), TEAE (5.3%), lack of efficacy (2.6%), non-adherence (0.9%) and other reasons (4.4%). Seizure frequency per 4 weeks decreased from a mean ± SD 5.0 ± 28.3 at baseline to 0.6 ± 2.1 during the whole observation period. Fifty-four patients (52.9%) were seizure free during the whole observation period. In addition, 69 of 95 patients (72.6%) whose topiramate therapy was stable within a range of ±50 mg/day for a period of at least 12 months (maintenance phase) were seizure free while treated with a median topiramate dose of 100 mg/day. The most frequently reported TEAEs were paraesthesias (13.2% of patients), dizziness (7.0%) and seizure-related events (7.0%). No significant differences between males and females were found for treatment response or retention.

Conclusion: Topiramate is an effective and well tolerated long-term treatment option for adolescents and adults with epilepsy.