Rapastinel Fails Phase 3 Trials

In March Allergan announced that a series of phase 3 studies of rapastinel as an adjunctive treatment for treatment-resistant major depressive disorder (MDD) did not meet their primary endpoints.

In two studies totaling 872 patients with MDD who had not responded adequately to an oral antidepressant, participants were randomized to 450 mg of rapastinel or placebo given once weekly as a bolus intravenous injection in addition to their oral antidepressant. A third study using a similar design of 638 participants included a third treatment arm of 225 mg rapastinel weekly. The primary endpoint for all three studies was the change in scores on the Montgomery-Åsberg Depression Rating Scale from baseline at the end of three weeks. In all three trials, scores for patients receiving rapastinel did not significantly differ from placebo.

Allergan is conducting a global phase 3 trial to evaluate rapastinel’s efficacy, safety, and tolerability as a monotherapy for MDD compared with placebo. It is also conducting a phase 2 proof-of-concept study evaluating efficacy, safety, and tolerability of rapastinel compared with placebo in addition to standard of care for patients with MDD at imminent risk of suicide. ■