Alkermes today announced positive topline results from the 12-week, randomized, double-blind, active-controlled, dose-ranging stage of a phase 2 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 2 study, Alkermes plans to request an End-of-Phase 2 meeting with the U.S. Food and Drug Administration (FDA) and advance ALKS 3831 into a pivotal development program in 2015.