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ALKS 3831 Well-Tolerated in Extension Study for Schizophrenia

October 05, 2019

SAN DIEGO—A year’s treatment with the investigational drug ALKS 3831 was generally well-tolerated and demonstrated a safety profile that supports long-term use, according to study findings presented during a poster session at Psych Congress 2019.

Under development for the treatment of schizophrenia, ALKS 3831 combines the antipsychotic olanzapine with samidorphan, which aims to mitigate olanzapine-associated weight gain.

The phase 3, open-label extension study enrolled 281 adults with schizophrenia. All completed a 4-week trial as inpatients before they were switched from ALKS 3831, olanzapine alone, or placebo to ALKS 3831 for the extension study, which lasted 52 weeks.

Alkermes to Seek Two Indications for ALKS 3831

Adverse events, most of which were mild, were reported by 49.1% of participants, according to the study. The most common adverse events were weight gain (13.4%), somnolence (8.3%), nasopharyngitis (4%), and headache (4%).

Average weight gain with a year’s use of ALKS 3831 was 1.86 kg (approximately 4.1 lb), a 2.79% increase in weight, researchers reported. No clinically significant changes in average laboratory measurements were observed.

The study also found improvements in schizophrenia symptoms over the 52 weeks. Specifically, Positive and Negative Syndrome Scale (PANSS) scores dropped an average 16.2 points from baseline, while Clinical Global Impression-Severity (CGI-S) scores decreased an average 9 points.

Alkermes Inc., the developer of ALKS 3831, funded the study.

—Jolynn Tumolo


Yagoda S, Graham C, Simmons A, Arevalo C, Cheng Y, McDonnell D. A phase 3, multicenter study to assess the long-term safety, tolerability, and efficacy of olanzapine/samidorphan in patients with schizophrenia. Poster presented at Psych Congress 2019: October 3-6, 2019; San Diego, CA. Poster 317.

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