AbbVie Completes Acquisition of Gilgamesh Pharmaceuticals' Bretisilocin

Rhea-AI Summary

AbbVie (NYSE: ABBV) completed its acquisition of Gilgamesh Pharmaceuticals' lead investigational candidate, bretisilocin, on Oct 17, 2025.

Bretisilocin is described as a novel, short-acting 5-HT2A receptor agonist and serotonin releaser currently in Phase 2 clinical development for moderate-to-severe major depressive disorder (MDD). AbbVie said the compound is next‑generation and designed to address development challenges seen with classic psychedelic therapies, and that the company plans to accelerate its development within AbbVie’s psychiatry pipeline.

Positive

• Acquisition completed on Oct 17, 2025
• Adds a Phase 2 psychiatry candidate (bretisilocin)
• Expands AbbVie’s psychiatry pipeline into psychedelic-derived therapeutics

Negative

• Bretisilocin remains in Phase 2—no approval yet
• Press release discloses no financial terms for the acquisition

• Acquisition expands AbbVie's psychiatry pipeline with the addition of a next-generation psychedelic compound currently in Phase 2 development for the treatment of major depressive disorder (MDD).

NORTH CHICAGO, Ill., Oct. 17, 2025 /PRNewswire/ -- AbbVie (NYSE: ABBV) announced today that it has completed its acquisition of Gilgamesh Pharmaceuticals' lead investigational candidate, bretisilocin.

Bretisilocin is a novel, short-acting serotonin 5-HT_2A receptor agonist and 5-HT releaser currently in Phase 2 clinical development for the treatment of patients with moderate-to-severe major depressive disorder (MDD). This next-generation 5-HT_2A receptor agonist is designed to help address current development challenges observed with classic psychedelic compounds.

"Recent clinical results have demonstrated the potential of bretisilocin to treat patients living with MDD," said Daniel Mikol, M.D., Ph.D., vice president, neuroscience development, AbbVie. "With the acquisition now complete, we look forward to accelerating the development of this next-generation compound, reinforcing AbbVie's commitment to delivering innovative, science-driven treatment options for people living with serious mental health conditions."

For additional background on the acquisition, please read the press release announcing the definitive agreement under which AbbVie will acquire bretisilocin here.

About AbbVie

AbbVie's mission is to discover and deliver innovative medicines and solutions that solve serious health issues today and address the medical challenges of tomorrow. We strive to have a remarkable impact on people's lives across several key therapeutic areas including immunology, oncology, neuroscience and eye care – and products and services in our Allergan Aesthetics portfolio. For more information about AbbVie, please visit us at www.abbvie.com. Follow @abbvie on LinkedIn, Facebook, Instagram, X (formerly Twitter) and YouTube.

Forward-Looking Statements 

Some statements in this news release are, or may be considered, forward-looking statements for purposes of the Private Securities Litigation Reform Act of 1995. The words "believe," "expect," "anticipate," "project" and similar expressions and uses of future or conditional verbs, generally identify forward-looking statements. AbbVie cautions that these forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially from those expressed or implied in the forward-looking statements. Such risks and uncertainties include, but are not limited to, challenges to intellectual property, competition from other products, difficulties inherent in the research and development process, adverse litigation or government action, changes to laws and regulations applicable to our industry, the impact of global macroeconomic factors, such as economic downturns or uncertainty, international conflict, trade disputes and tariffs, and other uncertainties and risks associated with global business operations. Additional information about the economic, competitive, governmental, technological and other factors that may affect AbbVie's operations is set forth in Item 1A, "Risk Factors," of AbbVie's 2024 Annual Report on Form 10-K, which has been filed with the Securities and Exchange Commission, as updated by its Quarterly Reports on Form 10-Q and in other documents that AbbVie subsequently files with the Securities and Exchange Commission that update, supplement or supersede such information. AbbVie undertakes no obligation, and specifically declines, to release publicly any revisions to forward-looking statements as a result of subsequent events or developments, except as required by law.

Media: Liz Tang, Ph.D. liz.tang@abbvie.com

Investors: Liz Shea liz.shea@abbvie.com

 

 

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SOURCE AbbVie

FAQ

What did AbbVie (ABBV) announce about bretisilocin on October 17, 2025?

AbbVie announced it completed the acquisition of Gilgamesh’s lead candidate, bretisilocin, on Oct 17, 2025.

What is bretisilocin and what stage is it at for ABBV?

Bretisilocin is a short-acting 5-HT2A receptor agonist and serotonin releaser in Phase 2 development for moderate-to-severe MDD.

How does the bretisilocin acquisition affect AbbVie’s pipeline (ABBV)?

The deal expands AbbVie’s psychiatry pipeline by adding a next-generation psychedelic-derived candidate intended to address development challenges of classic compounds.

Did AbbVie provide financial details for the Gilgamesh/bretisilocin acquisition?

No; the announcement does not disclose financial terms for the acquisition.

Will bretisilocin be immediately available to patients after AbbVie’s acquisition of Gilgamesh?

No; bretisilocin is still in Phase 2 clinical development, so further trials and regulatory steps are required before potential patient access.