Pharma BD Deal Intelligence

AbbVie Inc. / Gilgamesh Pharmaceuticals Inc.

2025 · Asset Purchase · $1.2B · Complete

AbbVie's up-to-$1.2B move for Gilgamesh's bretisilocin marks its first psychedelic-medicine bet, built on a Phase 2a MDD readout that hit statistically significant MADRS reduction versus a low-dose comparator — though the drug now has to prove a shorter in-office dosing edge is enough to matter commercially.

Outcome grade pending — assessed 5 years post-close.

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The coverage arc

Aug 25, 2025 BioPharma Dive Bullish

AbbVie has bought a psychedelic compound from a little known drug company, in a deal that could be worth north of $1 billion. The acquisition, announced…

Aug 25, 2025 Reuters Neutral

AbbVie said on Monday it would acquire privately held Gilgamesh Pharmaceuticals for up to $1.2 billion, gaining access to an experimental psychedelic medicine…

Feb 06, 2026 BioSpace Bullish

While AbbVie executives avoided going into many specifics regarding the pharma's new psychedelic drug, acquired for $1.2 billion from Gilgamesh Pharmaceuticals…

Source summaries from our enrichment pipeline; follow links for originals.

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AbbVie acquired Gilgamesh Pharmaceuticals' lead asset bretisilocin (GM-2505), a novel short-acting serotonin 5-HT2A receptor agonist and 5-HT releaser in Phase 2 development for moderate-to-severe major depressive disorder (MDD), for up to $1.2B (upfront plus development milestones). The deal was announced August 25, 2025 and completed October 17, 2025. As part of the transaction Gilgamesh spun off its remaining programs into a new independent entity, Gilgamesh Pharma Inc. Bretisilocin is designed for a shorter in-office dosing experience than classic psychedelics such as psilocybin, and the Phase 2a MDD study reported a statistically significant reduction in MADRS depression severity versus low-dose active comparator. The acquisition is AbbVie's first major move into psychedelic medicine, extending its neuropsychiatry pipeline beyond the assets gained in the Cerevel Therapeutics acquisition; AbbVie has stated it intends to accelerate bretisilocin into late-stage development.

Key facts

Disease & market context

Major Depressive Disorder (MDD) - short-acting psychedelic therapy

21M US cases/yr · $1.4B Spravato (esketamine) 2024 global sales - benchmark for rapid-acting depression market · 94% Bretisilocin Phase 2 remission rate in MDD (Gilgamesh Phase 2 data)

Disease Overview

Major depressive disorder (MDD) affects approximately 21 million US adults annually (8.3% of adults, NIMH), representing the single largest prevalent mental-health condition and a leading cause of disability. Treatment-resistant depression (TRD), defined as failure of two or more adequate antidepressant trials, affects approximately 30% of MDD patients - roughly 6.3 million US adults - and carries elevated suicide risk, high healthcare utilization, and substantial productivity loss. Standard-of-care SSRIs/SNRIs deliver remission in only 30-40% of initial-treatment patients with 4-6 week onset. J&J/Janssen's Spravato (esketamine nasal spray, approved 2019 for TRD, label expanded to monotherapy 2025) generated $1.4B in 2024 sales and validated the rapid-acting mechanism targeting NMDA/glutamatergic pathways. Compass Pathways' COMP360 psilocybin and MindMed's MM120 LSD represent second-wave serotonergic psychedelics in late-stage trials. Bretisilocin (GM-2505) from Gilgamesh is differentiated as a short-acting 5-HT2A agonist + 5-HT releaser designed for a 3-4 hour in-office experience, versus 6-8 hours for psilocybin - a potential commercial advantage for clinic throughput and payer adoption.

Competitive Landscape

The rapid-acting depression market is anchored by J&J's Spravato (esketamine nasal spray, $1.4B 2024 sales, NMDA antagonist), the first approved REMS-gated rapid-acting antidepressant. The second wave centers on serotonergic psychedelics acting via 5-HT2A receptor agonism. Compass Pathways' COMP360 (synthetic psilocybin, Phase 3 COMP005/006 in TRD, 2026 readouts) is the most advanced, with ~6-8 hour dosing session. MindMed's MM120 (lurasidone-controlled LSD, Phase 3 VOYAGE in GAD, Phase 2b positive in MDD) uses a ~8 hour session. atai Life Sciences/Beckley Psytech's BPL-003 (short-acting 5-MeO-DMT, ~2 hour session, Phase 2b TRD) and GH Research's GH001 (inhaled 5-MeO-DMT, Phase 2b TRD) compete directly on the short-acting thesis. Additional entrants: Lykos (MDMA, PTSD, FDA CRL 2024), Cybin's CYB003 (Phase 3 deuterated psilocin), and Delix Therapeutics' non-hallucinogenic psychoplastogens. Bretisilocin (GM-2505) is positioned as a 3-4 hour 5-HT2A agonist + 5-HT releaser, offering clinic-throughput and tolerability advantages over classical psychedelics. AbbVie inherits this asset plus an existing Cerevel neuropsych portfolio (tavapadon, emraclidine, darigabat), strengthening its post-Allergan/Cerevel depression pipeline.

Related deals — scored

DealYearValueOutcome
AbbVie Inc. / Gilgamesh Pharmaceuticals Inc. (this deal)2025$1.2B
AbbVie Inc. / Boehringer Ingelheim GmbH2016$2.2B95
AbbVie Inc. / Genmab A/S2020$3.9B81
AbbVie Inc. / Pharmacyclics Inc.2015$21.0B79
AbbVie Inc. / Apogee Therapeutics, Inc.2026$10.9B72
AbbVie Inc. / ImmunoGen Inc.2023$10.1B69
AbbVie Inc. / Gilgamesh Pharmaceuticals Inc.2024$2.0B64

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