Aripiprazole once-monthly for treatment of schizophrenia: double-blind, randomised, non-inferiority study

Background Long-acting injectable formulations of antipsychotics are treatment alternatives to oral agents. Aims To assess the efficacy of aripiprazole once-monthly compared with oral aripiprazole for maintenance treatment of schizophrenia. Method A 38-week, double-blind, active-controlled, non-inferiority study; randomisation (2:2:1) to aripiprazole once-monthly 400 mg, oral aripiprazole (10-30 mg/day) or aripiprazole once-monthly 50 mg (a dose below the therapeutic threshold for assay sensitivity). (Trial registration: clinicaltrials.gov, NC100706654.) Results A total of 1118 patients were screened, and 662 responders to oral aripiprazole were randomised. Kaplan-Meier estimated impending relapse rates at week 26 were 7.12% for aripiprazole once-monthly 400 mg and 7.76% for oral aripiprazole. This difference (-0.64%, 95% CI -5.26 to 3.99) excluded the predefined non-inferiority margin of 11.5%. Treatments were superior to aripiprazole once-monthly 50 mg (21.80%, P <= 0.001). Conclusions Aripiprazole once-monthly 400 mg was non-inferior to oral aripiprazole, and the reduaion in Kaplan-Meier estimated impending relapse rate at week 26 was statistically significant v. aripiprazole once-monthly 50 mg.