Comparison of Relapse Prevention with 3 Different Paliperidone Formulations in Patients with Schizophrenia Continuing versus Discontinuing Active Antipsychotic Treatment: A Post-Hoc Analysis of 3 Similarly Designed Randomized Studies

Background: Sudden discontinuation from antipsychotic treatment is a common occurrence in patients with schizophrenia. Lower rates of relapse could be expected for patients discontinuing treatment from longer-acting formulations vs their shorter-acting equivalents.

Objective: To compare relapse rates and time-to-relapse between the active (analogous to adherent patients) and placebo (analogous to non-adherent patients in the real-world) arms of three different formulations of paliperidone (oral paliperidone extended release [paliperidone ER], paliperidone palmitate once monthly [PP1M], and paliperidone palmitate three monthly [PP3M] long-acting injectables).

Methods: Data from three similarly designed, randomized relapse prevention studies in adult patients with schizophrenia were analyzed.

Results: In total, 922 patients were included (active treatment: 473, placebo: 449). Lowest percentage of patients experienced relapse with PP3M <PP1M <paliperidone and ER, in both the active treatment (PP3M, 9% <PP1M, 18% <paliperidone ER, 22%) and placebo (PP3M, 29% <PP1M, 48% <paliperidone ER, 52%) groups. The post-discontinuation median-time-to-relapse was significantly longer with PP3M (395 days [274 days to "not-reached"])> PP1M (172 days [134-222 days])> paliperidone ER (58 days [42-114 days]) and was "not-estimable" in the active treatment group due to low relapse rates. Hazard ratios (HR) of the three paliperidone formulations relative to their respective placebos were PP3M ([HR: 3.81; 95% CI: 2.08, 6.99; P< 0.0001]> PP1M [HR: 3.60; 95% CI: 2.45, 5.28; P<0.0001]> paliperidone ER [HR: 2.83; 95% CI: 1.73, 4.63; P<0.001]).

Conclusion: The lower percentage of relapse during active treatment and longer time to relapse after discontinuing active treatment with longer-duration antipsychotic formulations suggests the benefit of longer-acting over shorter-acting formulations, especially in patients susceptible to poor adherence.Clinical trial registration: paliperidone ER (NCT00086320), PP1M (NCT00111189), and PP3M (NCT01529515).