ALKS 3831, a combination of olanzapine and the opioid receptor antagonist samidorphan (OLZ/SAM), is associated with minimal weight gain, tolerable adverse events, and improved symptomology, according to the results of a 52-week, open-label extension study (ClinicalTrials.gov identifier: NCT02669758) of ENLIGHTEN-1 (ClinicalTrials.gov identifier: NCT02634346) presented at Psych Congress 2019, held October 3 to 6, in San Diego, California.
Study participants underwent clinical laboratory testing of fasting glucose, cholesterol, and hemoglobin A1c, as well as weight assessment and adverse event monitoring. Efficacy was assessed using the Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression-Severity scores.
Of the 281 patients enrolled in this extension study, 277 received ≥1 dose of the study drug, 248 had ≥1 postbaseline PANSS assessment, and 183 completed the study. The mean modal (SD) dose of olanzapine in OLZ/SAM was 15.9 (4.93) mg/d, with a mean (SD) treatment duration of 271 (140) days.
Overall, OLZ/SAM was generally well-tolerated. A minimal weight gain was observed during the 52-week extension, with a mean (SD) increase of 1.86 (6.69) kg from baseline. Adverse events were reported in 49.1% of the study participants; the majority were mild or moderate in severity and included increased weight, somnolence, headache, and nasopharyngitis.
OLZ/SAM resulted in durable antipsychotic effects, with improvements on both the PANSS and Clinical Global Impression-Severity scales. Overall mean (SD) changes from baseline to week 52 were -16.2 (15.41) in PANSS and -0.9 (0.92) in Clinical Global Impression-Severity (P <.001 for both). A ≥30% improvement from baseline in PANSS score was reported in 51.9% of patients who completed the study.
This extension study was an open-label study with no comparator group, which limits the conclusions that can be drawn. In addition, patients entered the extension study with different previous medication exposure, depending on their treatment group (placebo, OLZ/SAM, or olanzapine alone) during the 4 weeks of ENLIGHTEN-1.
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Disclosure: This clinical trial was supported by Alkermes, Inc. Please see the original reference for a full list of authors’ disclosures.
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 a combination of olanzapine and samidorphan in subjects with schizophrenia. Presented at: Psych Congress 2019; October 3-6, 2019; San Diego, CA. Poster 317.