The prospective economic impact of once monthly paliperidone palmitate versus oral atypical antipsychotics in Medicaid patients with schizophrenia.

Objectives: Multiple real-world studies have reported potential cost savings associated with second-generation antipsychotic long-acting injectable therapies (SGA-LAIs), including once monthly paliperidone palmitate (PP1M). Yet, only about 12% of Medicaid patients with schizophrenia initiate SGA-LAIs, with poor adherence contributing to frequent relapse among patients on oral atypical antipsychotics (OAAs). The objective of this study was to project the economic impact when an incremental proportion of non-adherent patients with a recent relapse switched from OAAs to PP1M.

Methods: A 12 month decision-tree model was developed from a Medicaid payers' perspective. The target population was non-adherent OAA patients with a recent relapse. At equal adherence, risk of relapse was equal between PP1M and OAAs, and OAA patients remained non-adherent until treatment switch. Outcomes included number of relapses, relapse costs and pharmacy costs.

Results: Based on a hypothetical health plan of 1 million members, 3037 schizophrenia patients were non-adherent on OAAs with a recent relapse. Compared to continuing OAAs, switching 5% of patients (n = 152) to PP1M resulted in net schizophrenia-related cost savings of $674,975 at a plan level, $4445 per patient switched per year and $0.0562 per member per month, with a total of 92 avoided relapses over 12 months. Total annual plan level schizophrenia-related costs were $114.1 M when all patients switched to PP1M before any subsequent relapse (n = 3037), $123.4 M when patients switched to PP1M after a first subsequent relapse (n = 2631), and $127.6 M when all patients continued OAAs. Switching all patients to PP1M before any subsequent relapse averted 917 relapses, at a lower cost per patient switched ($37,559) compared to switching after a first subsequent relapse ($45,089) or continuing OAAs ($42,005).

Conclusion: Over 12 months, pharmacy costs associated with switching patients from OAAs to PP1M were offset by reduced relapse rates and schizophrenia-related healthcare expenditures, with earlier use of PP1M projected to generate greater cost savings.