OBJECTIVES: Schizophrenia is associated with substantial economic burden on the US health care system. Olanzapine (OLZ), a 2^nd generation antipsychotic (AP) treatment has been an effective treatment for patients with schizophrenia has been associated with weight gain and cardiometabolic sequelae. During 2021, the US Food and Drug Administration approved a combination of OLZ and samidorphan (OLZ/SAM [LYBALVI®]) for the treatment of adults diagnosed with schizophrenia or bipolar I disorder. OLZ/SAM has demonstrated clinical efficacy of olanzapine but with less weight gain. The rates of discontinuations to AP are very high in patients with schizophrenia, leading to relapse rates. It is important to understand the potential economic impacts of relapse rates in schizophrenia patients initiated on OLZ/SAM versus OLZ to inform health care decision makers.

METHODS: A decision tree model from a US payer perspective was developed to examine the difference of relapse rates and the costs associated with these relapse rates among patients with schizophrenia who were initiated on OLZ/SAM or OLZ. Discontinuation rates were identified from clinical trials data and real-world data. Direct costs associated with inpatient and outpatient mental healthcare-related services were obtained from published studies and sources which included: psychiatric hospitalizations, emergency services, medication management, and outpatient individual therapy. Costs were inflated to 2022 US dollars. The mean direct incremental difference among the two groups was evaluated.

RESULTS: The relapse rates for OLZ/SAM and OLZ were 36% and 62%, respectively. The mean direct cost of one relapse rate was $50,778, and upon calculating the costs associated with relapse rates between OLZ/SAM versus OLZ, there was a 40% higher mean direct cost for patients on OLZ.

CONCLUSIONS: In this analysis, OLZ/SAM has 50% lower relapse rates during 1 year versus OLZ, and OLZ/SAM demonstrated a 60% cost-savings versus OLZ. OLZ/SAM could be considered as first line therapy due to better adherence measures.