09:26 AM EDT, 08/25/2025 (MT Newswires) -- AbbVie ( ABBV ) has agreed to buy Gilgamesh Pharmaceuticals' lead asset bretisilocin for up to $1.2 billion, including an upfront payment and development milestones, the companies said Monday.

As part of the deal, Gilgamesh will spin off an entity to be called Gilgamesh Pharma to hold its employees and other programs, including an ongoing collaboration and option-to-license agreement with AbbVie ( ABBV ) to develop treatments for psychiatric disorders, the companies said.

Bretisilocin, a psychedelic compound being developed to potentially treat people with moderate-to-severe major depressive disorder, showed a statistically significant reduction in the severity of depressive symptoms in a phase 2a study, according to a joint statement.

The deal is subject to closing conditions, the companies said.