AbbVie announced acquisition plans for Gilgamesh Pharmaceuticals' investigational psychedelic drug Bretisilocin, designed for major depressive disorder (MDD), with a potential total value of up to $1.2 billion. Bretisilocin, a 5-HT2A receptor agonist and serotonin releaser, demonstrated significant antidepressant effects in Phase IIa trials, accompanied by a shorter psychoactive profile compared to earlier psychedelics. The move reflects biopharma's increasing interest in novel modalities for psychiatric disorders, with AbbVie positioning to expand its neuropsychiatry portfolio through this promising candidate.