Phase III study of ALKS 3831 meets endpoints in schizophrenia.- Alkermes.

Alkermes announced positive topline results from ENLIGHTEN-2, a pivotal phase III study of ALKS 3831 (olanzapine/samidorphan), an investigational, novel, once-daily, oral atypical antipsychotic drug candidate for the treatment of schizophrenia. ENLIGHTEN-2 was a multicenter, double-blind, randomized, phase III study that evaluated the weight gain profile of ALKS 3831 compared to olanzapine over six months in 561 patients with stable schizophrenia. In the study, ALKS 3831 met the pre-specified co-primary endpoints, demonstrating both a lower mean percent weight gain from baseline at six months compared to the olanzapine group (p=0.003) and a lower proportion of patients who gained 10% or more of their baseline body weight at six months compared to the olanzapine group (p=0.003). With the successful completion of ENLIGHTEN-2, Alkermes plans to submit a New Drug Application (NDA) to the FDA in mid-2019.

In addition to meeting the co-primary endpoints, the study also met its pre-specified key secondary endpoint, with the ALKS 3831 treatment group demonstrating a lower proportion of patients who gained 7% or more of their baseline body weight at six months compared to the olanzapine group (p=0.001). Consistent with the phase II study of ALKS 3831, the weight gain curves for the ALKS 3831 and olanzapine treatment groups began to separate after Week 4 and continued to diverge for the remainder of the study. For the ALKS 3831 treatment group, weight stabilized at Week 6 and remained flat for the rest of the six-month treatment period. ENLIGHTEN-2 is the second of two key phase III studies in the ALKS 3831 registration program and was designed to confirm ALKS 3831's favorable weight profile compared to olanzapine, an antipsychotic agent with established efficacy but limited in its clinical use by a high incidence and magnitude of weight gain.

Comment: Alkermes expects to submit the results from the ENLIGHTEN-2 study to a peer-reviewed journal for publication and present full study results, including other endpoints and effects on metabolic parameters, at an upcoming scientific meeting.