Phase 3 Study of Aripiprazole Intramuscular Depot for the Maintenance Treatment of Schizophrenia

Otsuka and Lundbeck announced results from a Phase 3 clinical trial evaluating the efficacy, safety and tolerability of once-monthly aripiprazole intramuscular (IM) depot formulation for the maintenance treatment of adults with schizophrenia.

This Phase 3 multi-center, double-blind, placebo-controlled study included 710 adult patients with schizophrenia who required chronic treatment with an antipsychotic agent. The study was comprised of four phases: 1) an oral conversion phase (4-6 weeks) in which study patients not currently being treated with aripiprazole were converted to oral aripiprazole monotherapy; 2) an oral stabilization phase (4-12 weeks) in which all patients were treated with oral aripiprazole (10-30mg/day) until achieving pre-specified stability criteria for at least 4 weeks; 3) an IM depot formulation stabilization phase where patients received aripiprazole IM depot formulation injections every four weeks (400mg with a permissible single decrease to 300mg), with co-administration of oral aripiprazole during the first two weeks (N=576); and 4) a maintenance treatment phase where patients received an injection of aripiprazole IM depot formulation or placebo once every 4 weeks for 52 weeks (N=403). When patients participating in Phase 3 of the study met stability criteria for 12 weeks they were randomized (2:1) to aripiprazole IM depot formulation (N=269) or placebo (N=134) for the maintenance phase (Phase 4).

Aripiprazole IM depot formulation significantly delayed time-to-impending relapse compared to placebo, the primary endpoint of the study (Hazard ratio = 5.03, P<0.0001). In addition, improvements in the symptoms [as measured by the Positive and Negative Syndrome Scale (PANSS) total score] were maintained throughout the study in patients treated with aripiprazole IM depot formulation, while patients who received placebo reported significantly worsening scores (mean change from baseline at week 52 was 1.4 for aripiprazole IM depot formulation compared to 11.6 for placebo; LOCF analysis, P<0.0001).

Aripiprazole is an atypical antipsychotic. While the use of aripiprazole IM depot formulation is investigational, aripiprazole is currently approved and marketed as Abilify (BMS/Otsuka Partnership). Abilify is indicated for: use as an adjunctive therapy to antidepressants in adults with Major Depressive Disorder who have had an inadequate response to antidepressant therapy; acute treatment of manic or mixed episodes associated with Bipolar I Disorder as monotherapy and as an adjunct to lithium or valproate in adult and pediatric patients 10–17 years of age, maintenance treatment of Bipolar I Disorder, both as monotherapy and as an adjunct to lithium or valproate; treatment of Schizophrenia in adults and adolescents 13–17 years of age; and, treatment of irritability associated with Autistic Disorder in pediatric patients 6–17 years of age. Abilify Injection (BMS/Otsuka Partnership) is indicated for acute treatment of agitation associated with Schizophrenia or Bipolar Disorder, manic or mixed in adults.

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