Projecting the economic outcomes of switching patients with schizophrenia from oral atypical antipsychotics to once-monthly, once-every-3-months, and once-every-6-months paliperidone palmitate

BACKGROUND: Among patients with schizophrenia, nonadherence to oral atypical antipsychotics (OAAs) leads to increased risk of relapses, which entails substantial economic burden. OBJECTIVE: To evaluate the impact on health care costs and relapse rates of switching patients with schizophrenia from OAAs to once-monthly paliperidone palmitate (PP1M), with subsequent transitions to once-every-3-months (PP3M) and once-every-6-months paliperidone palmitate (PP6M). METHODS: A 36-month Markov model was developed from a Medicaid payer’s perspective. Two non–mutually exclusive subpopulations of adults with schizophrenia who were nonadherent to OAAs were considered: (1) recently relapsed and (2) young adults (aged 18-35). Patients were assumed nonadherent to OAAs until switching treatments, which was permissible multiple times during the 36-month period. Patients switching to PP1M could subsequently transition to PP3M and PP6M. Relapse rates were assumed consistent across treatments based on patients’ adherence. Model inputs were literature based. PP6M transition rates were assumed similar to PP3M. Cost savings were reported at the plan level and per patient switched. RESULTS: In a hypothetical health plan of 1 million Medicaid beneficiaries, an estimated 10,053 adults with schizophrenia were nonadherent to OAAs, among whom 7,454 were recently relapsed and 4,002 were young adults. Switching 5% of recently relapsed adults (N = 373) from OAAs to PP1M prior to subsequent relapse resulted in 541 relapses avoided and plan-level savings of $8.2M after 3 years. Incorporating transitions to PP3M/PP6M increased net savings to $9.1M and 631 relapses were avoided. Among young adults, switching 5% (N = 200) from OAAs to PP1M saved $1.8M at the plan level with 178 relapses avoided after 3 years. Including transitions to PP3M/PP6M, 3-year plan-level savings were $2.0M with 223 relapses avoided. Per recently relapsed patient switched to PP1M, and subsequently to PP3M/PP6M, cumulative 3-year cost savings were $22,100 and $24,300, respectively. Among young adults, corresponding 3-year cost savings per patient were $8,900 and $9,800. CONCLUSIONS: Switching nonadherent patients from OAAs to PP1M results in substantial cost savings and reduces relapse rates. Incorporating transitions to PP3M/PP6M leads to incremental cost savings and additional relapses avoided.