Rapid Antidepressant Effects and MADRS Item Improvements With AXS-05 (DEXTROMETHORPHAN-BUPROPION), an Oral NMDA Receptor Antagonist in Major Depressive Disorder: Results From Two Randomized Double-Blind, Controlled Trials

AXS-05 (dextromethorphan-bupropion) is an oral NMDA receptor antagonist being developed for major depressive disorder. In two double-blind, randomized, controlled 6-week trials, AXS-05 showed rapid antidepressant effects. In the placebo-controlled GEMINI trial (327 participants), AXS-05 was superior to placebo on depressive symptom improvement starting at Week 1, with greater improvement on the MADRS scale (7.3 vs. 4.9 points), higher response rates (15% vs. 7%), and by Week 2, higher remission rates (17% vs. 8%). In the ASCEND trial (80 participants) comparing AXS-05 to bupropion alone, AXS-05 was superior from Week 2 on MADRS improvement (12.5 vs. 7.8 points) and remission (26% vs. 3%). Common adverse events included dizziness, nausea, headache, diarrhea, somnolence, and dry mouth.

Study at a glance

Abstract

AbstractBackgroundAXS-05 (dextromethorphan-bupropion) is a novel, oral, investigational, NMDA receptor antagonist with multimodal activity being developed for MDD. The dextromethorphan component of AXS-05 is an NMDA receptor antagonist and a sigma-1 receptor agonist. The bupropion component of AXS-05 serves primarily to increase the bioavailability of dextromethorphan.MethodsAXS-05 was evaluated in two double-blind, randomized, controlled, 6-week trials. The GEMINI trial (N=327) was placebo-controlled and the ASCEND trial (N=80) used bupropion as the control. Here we focus on efficacy in the first 2 weeks of treatment and present a pooled analysis of the individual items of the MADRS for AXS-05 as compared to control.ResultsIn GEMINI, starting at Week 1, AXS 05 was superior (p < 0.05) to placebo on: mean MADRS improvement (7.3 vs. 4.9), MADRS response (15% vs. 7%), CGI-I (22% vs. 13%), CGI-S (0.7 vs. 0.4) and Q-LES-Q-SF (9.0% vs. 5.8%). At Week 2, AXS-05 was also statistically superior to placebo on MADRS remission (17% vs.8%) and on the SDS (6.8 vs. 4.5).In ASCEND, from Week 2, AXS-05 was superior (p< 0.05) to bupropion on: mean MADRS improvement (12.5vs. 7.8), MADRS remission (26% vs. 3%), and CGI-S (1.41 vs. 0.9).At Week 1, treatment with AXS-05 resulted in greater improvements (p< 0.05) in reported sadness, inner tension, inability to feel, pessimistic thoughts, and suicidal thoughts, as compared to control. At Week 6, AXS-05 demonstrated significant improvements over control on seven of the ten MADRS items.In the GEMINI trial, the most commonly reported adverse events were dizziness, nausea, headache, diarrhea, somnolence, and dry mouth.ConclusionsTreatment with AXS-05 resulted in rapid and broad antidepressant efficacy.FundingAxsome Therapeutics