Alkermes Phase II Results of ALKS 3831 Antipsychotic/Lower Weight Gain for Schizophrenia

Alkermes has announced positive topline results from the 12-week, randomized, double-blind, active-controlled, dose-ranging stage of a Phase II study of ALKS 3831, an investigational, novel, oral atypical antipsychotic drug candidate designed to be a broad-spectrum treatment for schizophrenia. ALKS 3831 is composed of samidorphan, a novel, potent mu-opioid antagonist, in combination with the established antipsychotic drug, olanzapine.

Data from the 300-patient study showed that ALKS 3831 achieved the study’s primary efficacy endpoint, demonstrating equivalence to olanzapine in reduction from baseline in Positive and Negative Syndrome Scale (PANSS) total scores at Week 12. ALKS 3831 also met the principal pre-specified secondary endpoint of the study, demonstrating a 37% lower mean weight gain compared to olanzapine at Week 12 in the full study population (p=0.006), and a 51% lower mean weight gain compared to olanzapine at Week 12 in a pre-specified subset of patients who gained weight in the one-week olanzapine lead-in (p<0.001). ALKS 3831 was generally well tolerated in the study. The most common adverse events in the ALKS 3831 treatment groups relative to olanzapine were somnolence, sedation and dizziness. Based on the positive results from this Phase II study, Alkermes plans to request an End-of-Phase II meeting with FDA and advance ALKS 3831 into a pivotal development programme in 2015.

“Olanzapine is considered one of the most efficacious atypical antipsychotics, yet it has one of the highest incidences and greatest amounts of weight gain among the widely prescribed products in this class of drugs, severely limiting its clinical use,” said Peter Weiden, Professor of Psychiatry at the University of Illinois Medical Center. “This study showed very promising results for ALKS 3831 in addressing the major drawback of weight gain in patients treated with olanzapine, and it offers the potential for widening the therapeutic use of an olanzapine agent to meet the needs of patients.”