Comparative efficacy of unique antiepileptic drug regimens in focal epilepsy: An exploratory study.

Objective: To compare efficacy of unique antiepileptic drug (AED) polytherapy regimens among patients with focal epilepsy.

Methods: From a longitudinal study of AED treatment, we identified patients with active focal epilepsy who had attempted at least two unique AED regimens (mono-, duo-, or tri-therapy). Efficacy was defined as the presence of at least one six-month period of continuous seizure freedom during exposure to a regimen. To control for individual variations in response and epilepsy severity, we used within-patient comparison approaches, in which we: 1) compared head-to-head unique regimens tried within the same patients; 2) compared one regimen versus aggregate of other regimens attempted in that patient; and 3) compared aggregated monotherapy versus polytherapy regimens.

Results: 757 patients met our criteria and had collectively attempted 170 unique regimens. In the head-to-head analysis, lamotrigine monotherapy was more effective than phenytoin monotherapy. Two regimens were more effective than the aggregate of other regimens attempted: levetiracetam/lamotrigine duotherapy and lamotrigine monotherapy. Two other regimens exhibited slightly better efficacy but did not reach statistical significance: clobazam/levetiracetam/lamotrigine and levetriacetam/oxcarbazepine. Patients who previously attempted at least four regimens had slightly better outcomes on polytherapy than monotherapy, though this was not significant.

Significance: We identified two unique regimens more likely to be associated with ≥6 months of seizure freedom: levetiracetam/lamotrigine duotherapy and lamotrigine monotherapy. Polytherapy may be an effective alternative to monotherapy for patients with focal epilepsy and persistent seizures.