AbbVie has agreed to purchase Gilgamesh Pharmaceuticals' investigational psychedelic drug candidate bretisilocin for up to $1.2 billion, including an upfront payment and development milestones. This deal marks AbbVie's ongoing expansion into the neuroscience and psychedelic therapy sectors, building on prior collaborations and acquisitions. Bretisilocin is under development for major depressive disorder and has shown promising Phase 2 results. Gilgamesh plans to spin off a new company for its remaining drug programs.