New antiepileptic drugs: Comparison of key clinical trials

Purpose: Data accrued from clinical trials of five new antiepileptic drugs (AEDs) are compared for efficacy in reducing seizures and self-reported adv erse events as a basis of selection among new AEDs. Drawbacks to use of the se data also are demonstrated. Methods: A review of double-blind, placebo-controlled clinical trials of a new AED or placebo added to a standard AED provided data on reduction of co mplex partial seizures (CPSs). Success is greater than or equal to 50% fewe r CPSs with a new AED or placebo; Overall Improvement is the success rate w ith drug minus the success rate with placebo. Adverse events were tabulated from product-labeling lists of COSTART items (incidence, greater than or e qual to 5%). The Summary Complaint score is the total number of reports of individual events for each AED. Results: Efficacy data demonstrate differences in Overall improvement rates among five new AEDs and placebos (p = 0.001). However, rates of response t o placebo also differed significantly among trials (p = 0.01). Adverse even ts predominantly affect central nervous system, psychiatric, and general bo dy systems. However, patients in the placebo control groups did not consist ently report adverse effects. Summary Complaint scores differ among the fiv e new AEDs, but variability in use of COSTART terms nullifies comparisons. Conclusions: Comparisons of data for five new AEDs provide information for selection among treatments when a second drug is needed to improve control of CPSs. However, significant differences among the control groups and othe r problems make comparisons between trials problematic. The final choice sh ould be based on the need of the individual patient for superior seizure co ntrol versus minimal adverse effects.