A Failed 6-Week, Randomized, Double-Blind, Placebo-Controlled Study of Once-Daily Extended Release Quetiapine Fumarate in Patients with Acute Schizophrenia: Lessons Learned

The efficacy of quetiapine XR (400, 600, and 800 mg/day) was not established at Week 6. Quetiapine IR, an agent with established efficacy in schizophrenia, also did not separate from placebo at endpoint. Therefore, this is considered a failed study and possible reasons for this are discussed. Quetiapine XR was generally well tolerated and its safety profile was consistent with the known profile of quetiapine.