Biotechnology & drug discovery · Psychiatry
Gilgamesh Pharmaceuticals
A New York chemistry shop that designed new psychedelic and ketamine-like molecules instead of licensing old ones. In August 2025 it sold its lead compound to AbbVie for up to $1.2 billion, then spun the rest of the pipeline into a new company.
The billion dollar closet
The office is ten feet by eight, in what used to be a therapist’s rooms near Union Square in Manhattan. A carving of an ancient god, a few books, a couch. The company is remote. The address is mostly an address.
“Billion-dollar headquarters right here,” Jonathan Sporn told a Forbes reporter there in September 2026, laughing. His co-founder Andrew Kruegel drew the contrast in the same conversation: “All the big VC-funded biotechs need their office in Boston with big glass windows.”
Ten months earlier, that closet had produced the first sale of a psychedelic compound to a large pharmaceutical company. AbbVie agreed in August 2025 to buy bretisilocin, a short-acting relative of DMT, for up to $1.2 billion in upfront and development milestones.
The problem they picked
More than 20 million people in the United States have major depressive disorder, and by the company’s own account up to two thirds of them do not reach remission after trying multiple antidepressants.
Psychedelics looked like an answer with a scheduling problem attached. A psilocybin session runs six hours or more. Johnson & Johnson’s esketamine spray, Spravato, established something different: a two hour in-clinic visit, and a network of clinics built to deliver it. Fit a psychedelic into that window and the existing infrastructure absorbs it.
Most psychedelic startups took the other route, developing compounds already in the public domain. Sporn refused. “There’s no way in hell we’re going to develop a generic drug,” he told Lucid News in 2023. Without composition of matter patents, he argued, no company could raise enough to carry a therapy to market, and no large partner would ever be interested.
A psychiatrist and a chemist
Sporn trained as a psychiatrist at Tufts and Harvard, worked at the National Institute of Mental Health under Dennis Charney, then spent years inside Johnson & Johnson and Pfizer learning drug development and growing frustrated with it. He bought a license to a Japanese arketamine patent for $30,000, built Perception Neuroscience around it, and sold that company to Atai.
Kruegel came from the other side. As a teenager in New Jersey he extracted sodium azide from an old airbag, converted it to lead azide, and set off a chip of it on the end of a six foot pole. In 2010 he went to Columbia to work in Dalibor Sames’s laboratory on ibogaine. He and Sames founded Kures, which Atai also bought, and which never produced a drug.
In spring 2019 Sporn called with a proposal: make new molecules with the properties they wanted rather than repurposing old ones. Sames, Sporn, Kruegel, Mike Cunningham and Jeff Witkin started Gilgamesh that summer. The company entered Y Combinator in 2020 and, by Forbes’s account, had raised $7.6 million after demo day. The chemistry is outsourced to a contract laboratory in India, directed from New York, much of it by email.
Six years to a sale
Two clinical programs carried the company. GM-1020, later named blixeprodil, is an oral NMDA receptor antagonist meant to give ketamine-like effects in a pill. GM-2505, later named bretisilocin, is a 5-HT2A agonist and serotonin releaser with a 45 minute half life. Both entered Phase 2 in 2024, both run through MAC Clinical Research in Manchester, England.
In May 2024 AbbVie paid $65 million upfront for an option on a separate class of non-hallucinogenic neuroplastogens, with up to $1.95 billion in later fees and milestones. That March, the National Institute on Drug Abuse backed GM-3009, an ibogaine analog engineered to remove ibogaine’s cardiac toxicity. Then came the bretisilocin data in May 2025, and three months after that, the AbbVie purchase. Under its terms Gilgamesh spun out a new entity, Gilgamesh Pharma Inc., holding the employees, the remaining programs and the AbbVie collaboration. That company closed a $60 million round in March 2026.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Bretisilocin Phase 2a, as reported | 40 patients, IV dosing. Day 14 MADRS change of 21.6 points on 10 mg versus 12.1 points on a 1 mg active comparator, p=0.003, effect size 1.0. Remission 70% at Day 14 and 94% at Day 29, with 17 of 20 patients carried into the Day 29 analysis. No serious adverse events. | Company-stated |
| The same study, as registered | NCT06236880 is a three-part study, 126 actual enrollment, actual primary completion July 27, 2026. The reported 94% comes from the 40-patient first part alone. Parts B and C are unpublished. | Public record |
| Blixeprodil Phase 2a | NCT06309277, 46 patients, completed March 4, 2025, topline announced January 6, 2026. MADRS difference of 6.3 points versus placebo at 24 hours (p=0.006). The Day 8 difference of 5.1 points did not reach significance (p=0.076). Combined remission 53% at Day 42. | Public record |
| Peer-reviewed work | GM-1020 rodent pharmacology in Neuropsychopharmacology, May 2024, and a GM-2505 healthy volunteer paper in the Journal of Psychopharmacology, January 2026. No peer-reviewed publication of either Phase 2a patient result was found as of September 22, 2026. | Public record |
| NIDA funding | The company announced a multi-year $14 million grant in March 2024. NIH RePORTER shows UG3DA060053 with $2,747,151 obligated in FY2024 and $841,274 in FY2025, a total of $3,588,425. | Announced exceeds obligated |
| AbbVie transactions | May 2024 option deal, $65 million upfront, up to $1.95 billion in aggregate fees and milestones. August 2025 purchase of bretisilocin for up to $1.2 billion. Neither party has disclosed the split between upfront and milestones. | Public record |
| Regulatory status | No FDA approval, no 510(k) and no PMA on record. Every program is investigational. AbbVie plans a bretisilocin Phase 3 for late 2026 or early 2027. | Public record |
| GM-3009 clinical entry | Expected to enter Phase 1 later in 2026, per the March 2026 financing release. No registered trial found as of September 22, 2026. | Not found |
Read plainly: Gilgamesh did what it set out to do commercially, and the science behind it is thinner than the headlines. Two mid-stage studies, 40 and 46 patients, one clinical research site, neither published in a peer-reviewed journal, produced a $1.2 billion asset sale and a $60 million financing. The 94% remission number is real, and it is also a Day 29 figure from 17 patients after an uncontrolled second dose. AbbVie is now paying to find out whether it holds at Phase 3 scale.
What to watch
- Results from Parts B and C of NCT06236880. AbbVie said in mid-2026 that two more Phase 2a cohorts would read out this year.
- Whether either Phase 2a result reaches peer review. As of September 2026 neither has.
- AbbVie’s bretisilocin Phase 3, planned for late 2026 or early 2027, and a Phase 2 in post-traumatic stress disorder.
- A registered Phase 1 for GM-3009, which the NIDA award was meant to fund through healthy volunteers and patients with opioid use disorder.
- Late-stage design for blixeprodil, where the company wants at-home dosing, a higher safety bar than supervised use.
In their words
“Billion-dollar headquarters right here”
Jonathan Sporn, co-founder and CEO, to Forbes, 2026 · Independent
“There’s no way in hell we’re going to develop a generic drug”
Jonathan Sporn, to Lucid News, 2023 · Independent
“I let the science and my work speak for itself”
Andrew Kruegel, co-founder and chief scientific officer, to Forbes, 2026 · Independent
“To have a strong effect on the brain, you have to have a strong effect on the brain. You can’t expect something that’s perceptually inert to transform your mind.”
Andrew Kruegel, to Forbes, 2026 · Independent
“Gilgamesh pioneered this whole style”
Rick Doblin, founder of MAPS, to Forbes, 2026 · Independent
“There hasn’t been a concerted effort to structurally optimize compounds to be drugs for a particular indication”
Andrew Kruegel, to Lucid News, 2023 · Independent
“The data from this Phase 2a trial are impressive, in particular the large and sustained remission rates.”
Maurizio Fava, MD, Mass General Brigham, in the company’s May 2025 release · Company release
“The use of a psychoactive control dose helps to manage the confound of functional unblinding, which is an issue with this class of investigational medicines”
Gerard Sanacora, MD, PhD, Yale Depression Research Program, to Clinical Trials Arena, 2025 · Independent
Related companies
Sources
- Public recordClinicalTrials.gov NCT06236880, GM-2505 in MDD
- Public recordClinicalTrials.gov NCT06309277, GM-1020 in MDD
- Public recordNIH RePORTER, UG3DA060053
- Public recordSEC EDGAR Form D filings, CIK 0001817048 and CIK 0002107396
- Public recordGM-1020: a novel, orally bioavailable NMDA receptor antagonist
- Public recordA novel psychedelic 5-HT2A receptor agonist GM-2505
- IndependentHow Gilgamesh Turned On Big Pharma’s Billion-Dollar Appetite For Psychedelic Drugs
- IndependentGilgamesh Tweaks Known Psychedelics To Improve Therapies
- IndependentAbbVie wagers more than $1B on Gilgamesh’s psychedelic drug
- IndependentAbbVie tunes in to Gilgamesh’s story, inking $1.2B deal
- IndependentGilgamesh’s psychedelic touts 94% remission rate in depression study
- IndependentAbbVie takes option on Gilgamesh CNS drugs in $2bn deal
- InterviewInsights on Bretisilocin From AJ Cannon, MD
- InterviewFeatured Founder: Gilgamesh Founder and CEO Jonathan Sporn
- CompanyPositive Topline Phase 2a Results for GM-2505 in MDD
- CompanyPositive Topline Phase 2a Results for Blixeprodil (GM-1020)
- CompanyGilgamesh Awarded $14 Million NIDA Grant
- PartnerAbbVie to Acquire Gilgamesh Pharmaceuticals’ Bretisilocin
- CompanyGilgamesh Pharma Closes Oversubscribed $60 Million Series A
- CompanyGilgamesh Pharma website, pipeline and leadership
- CompanyY Combinator company page, Summer 2020 batch
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
