Efficacy and safety of paliperidone palmitate 6-monthly long-acting injectable in reduction of relapses in patients with schizophrenia: An Asian subgroup analysis of phase 3, randomized study.

Background: Evaluate efficacy and safety of paliperidone palmitate 6-monthly (PP6M) for patients with schizophrenia in the Asian subgroup of a global, multicenter, noninferiority phase-3 study (NCT03345342).

Methods: Patients received paliperidone palmitate 1-monthly (PP1M, 100/150 mg eq.) or paliperidone palmitate 3-monthly (PP3M, 350/525 mg eq.) during the maintenance phase and entered a 12-month double-blind (DB) phase, wherein they were randomized (2:1) to PP6M (700/1000 mg. eq.) or PP3M (350/525 mg eq.). Subgroup analysis was performed for 90 (12.7%) patients from Asia region (India, Taiwan, Malaysia, Hong Kong, and Korea). Primary endpoint was time-to-relapse during DB phase (Kaplan-Meier estimates). Secondary endpoints were changes from baseline in Positive and Negative Syndrome Scale, Clinical Global Impression-Severity scale, Personal and Social Performance (PSP) scale score.

Results: In Asian subgroup, 91.9% (82/90) of patients completed DB phase (PP6M: 54/62 [87%]; PP3M: 28/28 [100%]). Median time-to-relapse was "not-estimable" due to low relapse rates in both groups. Estimated difference (95% confidence interval [CI]) between relapse-free patients in PP6M and PP3M groups of Asian subgroup was -0.1% [-8.5%, 8.4%] (global study population: -2.9% [-6.8%, 1.1%]). Mean change from baseline in secondary efficacy parameters was comparable between both groups, similar to the global study population. The incidence of extrapyramidal symptoms was higher in the Asian subgroup than in the global study population.

Conclusion: Consistent with the global study population, PP6M was noninferior to PP3M in preventing relapse in patients with schizophrenia from the Asia region. Findings suggest the possibility of switching from PP1M/PP3M to twice-yearly PP6M without loss of efficacy and with no unexpected safety concerns.