Descriptive analyses of the aripiprazole arm in the risperidone long-acting injectable versus quetiapine relapse prevention trial (ConstaTRE)

Abstract

A recent randomized, open-label, relapse prevention trial (ConstaTRE) compared outcomes with risperidone long-acting injectable (RLAI) versus the oral atypical antipsychotic quetiapine. This study also included a small descriptive arm in which patients could also be randomized to aripiprazole. Results of this exploratory analysis are described here. Clinically stable adults with schizophrenia or schizoaffective disorder previously treated with oral risperidone, olanzapine, or an oral conventional antipsychotic were randomized to RLAI or aripiprazole. Efficacy and tolerability were monitored for up to 24 months. A total of 45 patients were treated with aripiprazole (10-30 mg/day) and 329 patients with RLAI (25-50 mg i.m. every 2 weeks). Relapse occurred in 27.3% (95% CI: 15.0-42.8%) of aripiprazole-treated and 16.5% (95% CI: 12.7-21.0%) of RLAI-treated patients. Kaplan-Meier estimates of mean (standard error) relapse-free period were 313.7 (20.4) days for aripiprazole and 607.1 (11.4) days for RLAI patients. Remission was achieved by 34.1% (95% CI: 20.5-49.9%) of aripiprazole and 51.1% (95% CI: 45.5-56.6%) of RLAI patients. Clinical global impression-change was improved ("minimally improved" to "very much improved") in 26.4% with RLAI and 15.9% with aripiprazole patients. Tolerability was generally good for both treatment groups. Weight gain (7.0% with RLAI vs. 4.4% with aripiprazole), extrapyramidal adverse events (AEs) (10.3% vs. 4.4%), and potentially prolactin-related AEs (4.6% vs. 0%) were more common with RLAI treatment, and gastrointestinal disorders were more common in aripiprazole-treated patients (22.2% vs. 6.1%). Time-to-relapse in stable patients with schizophrenia or schizoaffective disorder was numerically longer in RLAI-treated patients than in aripiprazole-treated patients although not statistically significant. Both treatments were generally well tolerated.