Long-term cost-effectiveness of atypical antipsychotics in the treatment of adults with schizophrenia in the US

Ken O'Day,¹ Krithika Rajagopalan,² Kellie Meyer,¹ Andrei Pikalov,² Antony Loebel<sup>2

1</sup>Xcenda, Palm Harbor, FL, ²Sunovion Pharmaceuticals, Marlborough, MA, USA

Background: The purpose of this study was to evaluate the long-term cost-effectiveness (including hospitalizations and cardiometabolic consequences) of atypical antipsychotics among adults with schizophrenia.
Methods: A 5-year Markov cohort cost-effectiveness model, from a US payer perspective, was developed to compare lurasidone, generic risperidone, generic olanzapine, generic ziprasidone, aripiprazole, and quetiapine extended-release. Health states included in the model were patients: on an initial atypical antipsychotic; switched to a second atypical antipsychotic; and on clozapine after failing a second atypical antipsychotic. Incremental cost-effectiveness ratios (ICERs) assessed incremental cost/hospitalization avoided. Effectiveness inputs included discontinuations, hospitalizations, weight change, and cholesterol change from comparative clinical trials for lurasidone and for aripiprazole, and the Clinical Antipsychotic Trials of Intervention Effectiveness for other comparators. Atypical antipsychotic-specific relative risk of diabetes obtained from a retrospective analysis was used to predict cardiometabolic events per Framingham body mass index risk equation. Mental health costs (relapsing versus nonrelapsing patients) and medical costs associated with cardiometabolic consequences (cardiovascular events and diabetes management) were obtained from published sources. Atypical antipsychotic costs were estimated from Red Book^® prices at dose(s) reported in clinical data sources used in the model (weighted average dose of lurasidone and average dose for all other comparators). Costs and outcomes were discounted at 3%, and model robustness was tested using one-way and probabilistic sensitivity analyses.
Results: Ziprasidone, olanzapine, quetiapine extended-release, and aripiprazole were dominated by other comparators and removed from the comparative analysis. ICER for lurasidone versus risperidone was $25,884/relapse-related hospitalization avoided. At a $50,000 willingness-to-pay threshold, lurasidone has an 86.5% probability of being cost-effective, followed by a 7.2% probability for olanzapine, and 6.3% for risperidone. One-way sensitivity analysis showed the model is sensitive to lurasidone and generic risperidone hospitalization rates.
Conclusion: Generic risperidone is the least costly atypical antipsychotic. Lurasidone is more costly and more effective than risperidone and is cost-effective at willingness-to-pay thresholds of greater than $25,844 per hospitalization avoided. The favorable cost-effectiveness of lurasidone is driven by its clinical benefits (eg, efficacy in preventing hospitalizations in patients with schizophrenia) and its minimal cardiometabolic adverse effect profile.

Keywords: cost-effectiveness, economic, model, schizophrenia, atypical antipsychotic