A Prospective Study Comparing the Long-term Effectiveness of Injectable Risperidone Long-acting Therapy and Oral Aripiprazole in Patients with Schizophrenia

Abstract

Objective: To test the hypothesis that long-term maintenance with injectable risperidone long-acting therapy is superior to oral daily aripiprazole in stable patients with schizophrenia.

Design: This two-year, rater-blinded, open-label, multicenter study (NCT00299702) randomized subjects to injectable risperidone long-acting therapy (25-50mg, injected every 2 weeks) or oral aripiprazole (5-30mg/day), with study visits every two weeks. Subjects who met relapse criteria or discontinued study drug could remain in the study.

Setting: Clinical trial.

Participants: Stable subjects with schizophrenia not adequately benefiting from current treatment who experienced two or more relapses in the past two years. If recently relapsed, subjects were stabilized (per clinician judgment) for two or more months before entry.

Measurements: Primary endpoints: time to relapse and time in remission. Safety assessments included adverse event reporting.

Results: Of 355 subjects randomized, 349 were in the intent-to-treat analysis set. Data inspection revealed that 53 (14.9%) randomized subjects deviated from inclusion/exclusion criteria, most commonly not meeting stability requirements. At baseline, mean (standard deviation [SD]) Positive and Negative Syndrome Scale total score was 68.9 (14.6); 115 (33.0%) intent-to-treat subjects met remission criteria. Approximately 29 percent in each group discontinued the study before completing two years. No significant between-group differences were noted in time to relapse or time in remission. No new tolerability issues were identified.

Conclusion: RESULTS failed to demonstrate superiority with injectable risperidone long-acting therapy versus oral aripiprazole. The study design did not allow for valid conclusions of equivalence or noninferiority. Although this study attempted to mimic a real-world treatment setting for stable patients, the broad study population, the lack of patient selection for nonadherence, biweekly visits, regular assessments, and other design issues limited generalizability and interpretation relative to the study hypothesis.

Keywords: antipsychotic; aripiprazole; injectable risperidone long-acting therapy; schizophrenia.

Figure 1

Study design. RLAT

risperidone long-acting therapy

Figure 2

Kaplan-Meier plot for time to relapse (ITT analysis set) RLAT

risperidone long-acting therapy

ITT

intent-to-treat

P=0.684 (log-rank test stratified with pooled site)