AbbVie and Gilgamesh Pharmaceuticals, a New York-based clinical-stage bio/pharmaceutical company developing new chemical entities for psychiatric diseases, have entered an agreement under which AbbVie will acquire Gilgamesh’s lead investigational candidate, bretisilocin, for treating moderate-to-severe major depressive disorder (MDD), for $1.2 billion.  

Bretisilocin is a short-acting serotonin (5-HT)2A receptor agonist and 5-HT releaser and a psychedelic compound designed to address development challenges observed within this class of compounds. Psychedelic compounds, including 5-HT2A receptor agonists, are being evaluated as potential treatments for mental health disorders, such as MDD, because of their more durable antidepressant effects, according to information from AbbVie. However, existing agents in this class challenged by their long duration of psychoactive experience. Bretisilocin has been shown to exert a shorter duration of psychoactive experience while retaining an extended therapeutic benefit, according to the company.  

Under the agreement, AbbVie will acquire Gilgamesh’s bretisilocin program for up to $1.2 billion, inclusive of an upfront payment and development milestones. Additionally, as part of the transaction, Gilgamesh will spin off a new entity that will operate under the name Gilgamesh Pharma Inc. to hold its employees and other programs, including its oral N-methyl-D-aspartate (NDMA) receptor antagonist, blixeprodil (GM-1020), its ibogaine analog, its M1/M4 agonist program, and its existing collaboration with AbbVie. The transaction is subject to customary closing conditions. 

In 2024, AbbVie and Gilgamesh formed a collaboration and option-to-license agreement to advance the development of therapies for the treatment of psychiatric disorders. This option-to-license remains in effect and will be transferred to Gilgamesh Pharma Inc. in connection with the spin-out. 

Source: AbbVie