Notting Hill

Researchers are studying the effects of CYB003, a deuterated psilocin analog, compared to a matching placebo as an additional treatment for adults with Major Depressive Disorder MDD. This Phase III study aims to evaluate the safety, tolerability, and effectiveness of two different doses of CYB003 alongside participants current antidepressant medications and psychological support. Participants will be randomly assigned to one of three groups one receiving 8 mg of CYB003, another receiving 16 mg of CYB003, or a placebo group. Each participant will undergo two dosing sessions about three weeks apart while continuing their usual antidepressant treatment and receiving manualized psychological support from a facilitator. Non-responders in the placebo group may have the chance to receive CYB003 in an extension trial. During the study, participants will complete several assessments including the Montgomery-Asberg Depression Scale MADRS, Beck Depression Inventory-II BDI-II, Clinical Global Impression Scale CGI-S, Generalized Anxiety Disorder 7-Item Scale GAD-7, and Quality of Life Enjoyment and Satisfaction Questionnaire Q-LES-Q-SF. These evaluations occur at multiple timepoints from screening through the end of the trial. Safety and tolerability will be closely monitored throughout the study, with the total duration lasting approximately 12 weeks from baseline to study end.