Clinical effectiveness of paliperidone palmitate 3-monthly and 1-monthly as monotherapy in patients with schizophrenia: A retrospective cohort study based on the Medicaid claims database

Aim: Real-world data (RWD) for paliperidone palmitate (PP) three- monthly (PP3M) is lacking based on Japan label requirements. This study evaluated the clinical effective-ness of PP3M versus PP once- monthly (PP1M) in patients with schizophrenia admin-istered according to Japan label requirements. Methods: Retrospective analyses were conducted using RWD from Merative (TM) MarketScan (R) Multi-State Medicaid (MDCD) claims database (June 2015-December 2022). Adult patients with schizophrenia switching from PP1M to PP3M were in-cluded. Patients transitioning to PP3M were matched with patients who continued with PP1M using propensity score matching (PSM) at 1:1 ratio. Primary hypothesis aimed to investigate non-inferiority of PP3M versus PP1M in terms of relapse-free status at 24 months from index PP injection. Outcome measures were proportions of relapse-free patients at 24 months, time to relapse, treatment persistence, and adherence. Results: Total 4252 eligible adult schizophrenia patients on PP (PP3M:582; PP1M:3670) were identified. After PSM, each PP cohort comprised 562 matched in-dividuals. Estimated proportion of relapse-free patients was higher in PP3M (85.7%) versus PP1M (77.9%), per Japan PP label. PP3M demonstrated superiority to PP1M after testing for non-inferiority in terms of achieving relapse-free status at 24 months, with an estimated difference of 7.8% (95% CI: 1.7%-13.9%). PP3M cohort had lower risk of relapse (HR: 0.605; CI: 0.427-0.856), longer treatment persistence, and higher treatment adherence versus PP1M cohort. Conclusions: Findings suggests that patients who switched to PP3M might be able to reduce risk of relapse compared to those who continued PP1M after aligning particu-larly with Japan's label requirements