Phase 1 (Part A):~The primary objective of this study is to assess the safety and tolerability of single doses of GH001 (containing 5-methoxy-dimethyltryptamine; 5-MeO-DMT) in patients with TRD.~The secondary objectives of the study are to assess the effects of single doses of GH001 on various measures of depression, and on dose-related psychoactive effects.~Phase 2 (Part B):~The primary objective of this study is to assess the effects of an individualized dosing regimen of GH001 on the severity of depression.~The secondary objectives of the study are to assess the safety and tolerability of an individualized dosing regimen of GH001 in patients with TRD and its effects on the severity of depression, other measures of depression, and on dose-related psychoactive effects.~Study design: Phase 1/2 study in two parts.~Intervention: In the Phase 1 (Part A), a single dose of GH001 will be administered per patient. Two different dose levels will be investigated with four patients at each dose level. In the Phase 2 (Part B), an individualized dosing regimen will be administered.~In both parts, GH001 will be administered via inhalation.
The aim of the study is to investigate the safety of GH001 (containing 5-methoxy-dimethyltryptamine; 5-MeO-DMT), and to investigate its effects on severity of depressive symptoms, and its dose-related psychoactive effects in patients with Treatment-Resistant Depression (TRD).~The study is comprised of two open-label, single-arm study parts where Part A evaluates single doses of GH001 at two dose levels and Part B evaluates a specific individualized dosing regimen of GH001.