Olanzapine/Samidorphan: New Drug Approved for Treating Bipolar I Disorder and Schizophrenia

Objective To describe the approval of olanzapine/samidorphan, compare the clinical trial data, and summarize key findings, with a focus on impact to clinical practice. Data Sources A literature search of PubMed was performed (March 2006 to November 2021) using the following search terms: Lybalvi, olanzapine/samidorphan, olanzapine, antipsychotic, bipolar disorder, and schizophrenia. Product monographs, review articles, and randomized control trials were reviewed. Study Selection and Data Extraction Relevant English-language studies conducted in humans were considered. Primary use of Phase III clinical drug approval trials preferred; supplementary trial analysis evaluated to provide context. Data Synthesis In June 2021, the Food and Drug Administration (FDA) approved Lybalvi® (olanzapine/samidorphan) for indications including treatment of adults with schizophrenia and/or bipolar I disorder (acute manic episodes or acute episodes with mixed features) through the multi-stage ENLIGHTEN clinical trials. Participants were enrolled in 4-week, 24-week, and 52-week studies to evaluate the safety and efficacy of olanzapine/samidorphan. Subsequent secondary analysis evaluated metabolic effects. Relevance to Patient Care and Clinical Practice This review details the pharmacologic, pharmacokinetic, associated dosing and indications, and adverse effects for the drug combination olanzapine/samidorphan. Better understanding of novel drug mechanisms will help to expand on the potential role and place for use in clinical practice. Conclusion When treating complex patients with schizophrenia, the olanzapine/samidorphan combination has limited effect on medication-induced weight gain often associated with antipsychotic olanzapine monotherapy. Additional studies are needed to further define the role of olanzapine/samidorphan in bipolar I disorder and clinical practice.