GH001 Efficacy is Independent of Prior Antidepressant Treatment Failures in Treatment-Resistant Depression: A Post Hoc Analysis of a Phase 2b Randomized Controlled Trial.
Psychopharmacology bulletin June 5, 2026 Michael E Thase, Brian Brennan, Rachael Macisaac et al.
In patients with treatment-resistant depression, a single-day individualized dosing regimen of inhaled GH001 (synthetic mebufotenin) produced rapid and large improvements in depressive symptoms compared with placebo in a Phase 2b trial, with 57.5% achieving remission at Day 8 versus 0% on placebo. A post hoc analysis of 40 patients who received GH001 found no meaningful correlation between the number of prior lifetime antidepressant treatment failures and improvement on the Montgomery-Åsberg Depression Rating Scale at Day 8 or among 6-month open-label extension completers. Remission rates at Day 8 were similar across subgroups with 2, 3, 4, or 5 or more prior failures (range 53.9%-63.6%) and were maintained at Month 6 (range 61.5%-85.7%). The efficacy of GH001 appears largely independent of how many prior antidepressant treatments a patient has tried.