Pfizer Inc. (NYSE: PFE) today announced top-line results of a double-blind, placebo-controlled, Phase 3 study evaluating both the 165 mg dose and the 330 mg dose of pregabalin controlled-release (CR) formulation in adult patients with partial onset seizures with epilepsy. These study results indicate pregabalin CR did not meet its primary endpoint comparing the change in seizure frequency to placebo, although both doses were well-tolerated. This study is one of three Phase 3 studies of the pregabalin CR formulation, which will ascertain the potential use of pregabalin as a once-a-day therapy. The other two studies are evaluating the pregabalin CR formulation in fibromyalgia and post-herpetic neuralgia. Pfizer will continue to further analyze these top-line results as well as the top-line results of the other two studies. "While the study showed an observed improvement, it did not show a statistically significant difference in seizure frequency, which we believe may have been due to a higher-than-expected placebo response," said Steven J. Romano, M.D., senior vice president, head, Medicines Development Group, Global Primary Care Business Unit, Pfizer Inc. "Lyrica immediate-release has a proven success record in patients with epilepsy, and we look forward to understanding further the potential role of a once-a-day pregabalin formulation." Epilepsy is a chronic disorder in which seizures occur intermittently. Partial onset seizures (simple, complex, and secondarily generalized tonic-clonic) are the most common. In the U.S., the immediate-release formulation – Lyrica ® (pregabalin) capsules CV has been used as adjunctive therapy for partial onset seizures since its approval in June 2005. About the Study The objective of the double-blind, randomized, parallel group, multi-center study was to assess the efficacy and safety of pregabalin CR as adjunctive treatment of partial onset seizures in adult patients with epilepsy. The study was conducted in a total of 18 countries at 66 sites. The study included four phases: Phase 1 - an 8 week baseline phase during which the baseline seizure rate was recorded; Phase 2 - a 2 week double-blind dose escalation phase; Phase 3 - a 12 week double blind maintenance phase where the dosage of study medication was fixed; and Phase 4 - a 1 week taper phase at the conclusion of the study. Treatment groups included pregabalin CR 165 mg/day, pregabalin CR 330 mg/day or placebo at a 1:1:1 ratio. These pregabalin CR dose levels provided exposure similar to 150 mg and 300 mg daily doses of currently available Lyrica (pregabalin) immediate-release formulations.