A double-blind, randomized, active-controlled, parallel-group, noninferiority trial (NCT03345342) demonstrated that paliperidone palmitate once-every-6-months (PP6M) was noninferior to paliperidone palmitate once-every-3-months (PP3M) in preventing relapse in clinically stable adults with schizophrenia. This post hoc analysis assessed efficacy and safety following transition to PP6M from paliperidone once-monthly (PP1M) versus PP3M.

Adults with schizophrenia who were clinically stable on moderate/high doses of PP1M or PP3M were randomly assigned 1:2 to dorsogluteal PP3M or PP6M treatment for 12 months. The primary efficacy measure was time to relapse during the 12-month DB phase. Secondary endpoints included change from DB baseline to endpoint in Positive and Negative Syndrome Scale (PANSS) total and subscale scores, Clinical Global Impression-Severity (CGI-S) scale score, and Personal and Social Performance (PSP) scale score. Safety was assessed by treatment-emergent adverse events (TEAEs), vital signs, and clinical laboratory tests.

Of 702 patients in the study, 231 transitioned from PP1M to PP6M and 247 transitioned from PP3M to PP6M. Low relapse rates for PP6M were observed regardless of transition pathway (PP1M/PP6M: 7.8%; PP3M/PP6M: 7.3%). Changes from DB baseline to endpoint in PANSS total, PSP, and CGI-S scores were similar between transition groups. In the DB phase, ≥1 TEAE was observed in 61.0% and 63.2% of patients in the PP1M/PP6M and PP3M/PP6M, groups, respectively.

Adults with schizophrenia who transitioned to PP6M from either PP1M or PP3M experienced similarly low relapse rates. Additionally, symptom and functionality scores supported the primary analysis and, along with TEAE incidences, were comparable between transition groups.