Presentation (CTI)

OBJECTIVES: Second-generation antipsychotic (SGA) long-acting injectables (LAIs) have shown promise in preventing relapses compared to traditional oral medications, largely due to improved medication adherence achieved through long-acting formulations. Our objective was to compare the cost-effectiveness of four intramuscular SGA LAIs (aripiprazole, aripiprazole lauroxil, olanzapine pamoate, and risperidone) to paliperidone palmitate in patients with schizophrenia from the US health care sector perspective.
METHODS: A Markov model with 90-day cycles was developed to simulate the progression of 40-year-old adults transitioning among stable treated, stable non-treated, and relapse health states, and death over 5 years at a discount rate of 3%. The base case utilized a 5-year time horizon due to uncertainty in long-term treatment changes, adherence, and schizophrenia progression. Patients transitioned to additional lines of therapy (another SGA LAI and then clozapine) when they experienced relapse or intolerance to side effects. Relapse transitional probabilities were estimated from an analysis using administrative claims. Other treatment related input parameters were derived from clinical trials and observational studies. Health state utilities and disutilities were obtained from published literature. Drug costs were estimated from Medicare Average Sales Price. All costs were standardized to 2024 US dollars. One-way and probabilistic sensitivity analyses were conducted.
RESULTS: Compared to paliperidone (3.20 quality-adjusted life-years [QALYs]), all other SGA LAIs had slightly lower to similar QALYs ranging from 3.04 to 3.21. Total health care sector costs were comparable across the SGA LAIs. Risperidone was dominant compared to paliperidone with similar QALYs but slightly lower costs. One-way sensitivity analyses resulted in utility inputs and drug costs being most influential to the model.
CONCLUSIONS: Our estimation of 5-year costs and outcomes demonstrated similar total costs and QALYs across the SGA LAIs. Further studies to refine model inputs are needed to better differentiate between the SGA LAIs and to validate our findings.