Does Half-Life Matter After Antipsychotic Discontinuation? A Relapse Comparison in Schizophrenia With 3 Different Formulations of Paliperidone.

OBJECTIVE

To evaluate the effect of 1 oral and 2 distinct long-acting injectable (LAI) formulations of the same antipsychotic on times to relapse following medication discontinuation.

METHODS

Data were drawn from 3 similarly designed, multicenter, double-blind, placebo-controlled, randomized-withdrawal studies of paliperidone in adults with a schizophrenia diagnosis (according to DSM-IV criteria for ≥ 1 year before screening): once-daily extended-release oral paliperidone (ORAL paliperidone), once-monthly paliperidone palmitate (PP1M), and once-every-3-months paliperidone palmitate (PP3M). In a post hoc analysis, we compared median time to relapse across the treatment-withdrawal arms of the 3 studies using final analysis datasets. Time to relapse in the withdrawal arm of each study was examined using log-rank tests and Cox proportional hazards models.

RESULTS

Four hundred forty-nine patients were withdrawn from 3 paliperidone formulations: 101 from ORAL paliperidone, 203 from PP1M, and 145 from PP3M. Postwithdrawal median (95% confidence interval [CI]) days to relapse were 58 days (42-114 days) for ORAL paliperidone, 172 days (134-222 days) for PP1M, and 395 days (274 days-not reached) for PP3M (P < .0001, pairwise comparisons). Relapse risk was significantly lower (P < .001) for patients who withdrew from either PP formulation relative to ORAL paliperidone and additionally for patients who withdrew from PP3M relative to PP1M.

CONCLUSIONS

Results demonstrate that 50% of patients who withdrew treatment from ORAL paliperidone, PP1M, or PP3M remained relapse free for approximately 2 months, 6 months, and 13 months, respectively. This may be relevant for risk mitigation strategies in schizophrenia, a condition in which interruptions in maintenance antipsychotic treatment are commonplace and unpredictable. LAI antipsychotic formulations may provide substantial delays over oral equivalents in times to relapse when patients discontinue therapy.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT00086320, NCT00111189, and NCT01529515.