Olanzapine/Samidorphan Demonstrates Favorable Safety Profile in 4-Year Open-Label Study

Combination olanzapine/samidorphan (OLZ/SAM) maintained consistent symptom control in patients with schizophrenia or bipolar I disorder and demonstrated a favorable long-term safety profile over 4 years consistent with previous studies.

Results from the phase 3, multicenter, open-label, long-term extension were reported via poster at Psych Congress 2024 by Christina Arevalo, director, clinical program management of Alkermes, Inc. The study was sponsored by Alkermes, with support from Peloton Advantage, LLC.

The open-label study enrolled 524 patients who completed the ENLIGHTEN clinical trial program; participants could receive 2 to 4 years of additional treatment. Safety assessments included incidences of adverse events and changes from baseline in body weight, waist circumference, and lipid/glycemic parameters. Authors measured durability of effect using the Clinical Global Impressions-Severity (CGI-S) scale.

Most patients in the study had diagnosed schizophrenia/schizophreniform disorder (91%), while the remained had bipolar I disorder (9%). Mean age was 35.1 years, and mean OLZ/SAM exposure was 652.4 days.

The most common adverse events reported were weight gain, headache, anxiety, insomnia, somnolence, nausea, and weight loss. At the 2-year mark, mean change in body weight was 0.84 kg, while mean waist circumference change was -0.56 cm. At 4 years, mean change in body weight was 2.65 kg, while mean waist circumference change was 1.37 cm. Minimal changes were observed in lipid and glycemic measures. CGI-S scores were stable, with a –0.18 reduction at year 2 and –0.24 at year 4.

“OLZ/SAM maintained symptom control with a long-term safety profile over 4 years consistent with prior studies, highlighting its clinical benefits as a maintenance treatment in patients with schizophrenia or bipolar I disorder,” study authors concluded.

Reference

Arevalo C. Long-term safety and efficacy of olanzapine/Samidorphan: Results of a 4-year open-label study. Poster presented at: Psych Congress; October 29-November 2, 2024; Boston, Massachusetts.