Olanzapine-Samidorphan for Schizophrenia: A Systematic Review and Meta-Analysis

Background and Objective: United States Food and Drug Administration (USFDA) recently approved a novel combination of olanzapine-samidorphan (OLZSAM) for managing olanzapine-associated adverse events (weight gain) in adult patients with schizophrenia and bipolar disorder. To opine about the safety and efficacy of OLZSAM, authors performed a systematic review and meta-analysis to convene justifiable evidence. Methods: A thorough literature search was performed through the databases Embase, Cochrane Library, PubMed, and clinicaltrials.gov, from inception to September 2022, with the keywords: 'olanzapine and samidorphan' and schizophrenia; and "ALKS3831" and "lybalvi." Clinical trials published in English that analyzed the efficacy and safety of OLZSAM were included. The significant outcomes included in this study were change from baseline (CFB) in Positive and Negative Syndrome Scale (PANSS) at the end of the study, the proportion of patients with weight gain at the end of the study, the proportion of patients with at least one adverse event, and the incidence of drug discontinuation due to adverse events. Results: The change in PANSS score at the end of the study was comparable among groups receiving OLZSAM and olanzapine alone: standardized mean difference (SMD) = 0.04; 95% CI = -0.09 to 0.17; p = 0.57. The OLZSAM group reported less incidence of weight gain: risk ratio (RR) = 0.91; 95% CI = 0.62-1.34; p = 0.63, and any adverse event: RR = 0.99; 95% CI = 0.90-1.09; p = 0.81. Drug discontinuation incidence was higher in the OLZSAM group: RR = 1.22; 95% CI = 0.84-1.79; p = 0.30. Conclusions: The combination OLZSAM showed comparable efficacy to olanzapine alone in schizophrenia patients, with relatively less incidence of weight gain and adverse events; however, the drug discontinuation due to adverse events was more in the OLZSAM group.