Enveric Biosciences Secures Patent Victory as AbbVie Withdraws Challenge Following $1.2 Billion Gilgamesh Acquisition
Key Insights
Gilgamesh Pharmaceuticals (search) has withdrawn its Post-Grant Review petition challenging Enveric Biosciences (search)' patent covering halogenated psilocybin derivatives, leaving the patent unchallenged.
The withdrawal follows AbbVie (search)'s $1.2 billion acquisition of Gilgamesh and its bretisilocin (search) (GM-2505) compound, which appears relevant to Enveric's patent claims.
Enveric's patent portfolio protects next-generation psychedelic compounds and neuroplastogenic therapeutics, with lead candidate EB-003 targeting both 5-HT₂A and 5-HT₁B receptors for psychiatric disorders (search).
Enveric Biosciences (search) has emerged victorious in a patent dispute with Gilgamesh Pharmaceuticals (search), as the challenger has withdrawn its Post-Grant Review petition against Enveric's U.S. Patent No. 12,138,276 covering halogenated psilocybin derivatives. The withdrawal comes after AbbVie (search)'s acquisition of Gilgamesh in a deal valued at up to $1.2 billion, effectively ending all pending challenges to Enveric's intellectual property.
Patent Dispute Timeline and Resolution
The patent battle began on August 12, 2025, when Gilgamesh filed a Post-Grant Review petition with the United States Patent and Trademark Office's Patent Trial and Appeal Board (PTAB) challenging Enveric's '276 patent. The patent, titled "Halogenated psilocybin derivatives and methods of using," includes claims that appear relevant to bretisilocin (search) (GM-2505), the molecule Gilgamesh was developing in clinical trials.
Just two weeks later, on August 25, 2025, AbbVie (search) announced its agreement to acquire bretisilocin (search) from Gilgamesh in a definitive transaction valued at up to $1.2 billion. By November 7, Gilgamesh had become a wholly owned subsidiary of Warka Intermediate LLC, which is itself a wholly owned subsidiary of AbbVie.
Enveric responded to the patent challenge by hiring intellectual property firm Fish and Richardson P.C. in October 2025. The firm filed a Request for Discretionary Denial of the PGR petition on October 24, 2025. On November 20, counsel for AbbVie (search) filed a request with the USPTO to withdraw the petition Gilgamesh had originally filed, which the PTAB subsequently granted.
Strategic Implications for Psychedelic Drug Development
"Enveric is gratified by this turn of events, which we believe demonstrates our willingness to fully defend the intellectual property that protects our valuable discoveries," said Joseph Tucker, Director and CEO of Enveric. "The withdrawal of the petition resolves the proceeding and leaves our issued patent unchallenged. We believe it reflects both the strength of our intellectual property and our willingness to defend it when necessary."
Tucker emphasized the broader significance of the patent portfolio, stating that "the fact that the PGR petition was filed in the first place underscored the breadth of our intellectual property footprint in the field, embodied by the numerous discoveries pertaining to next-generation, small-molecule psychedelics and potential non-hallucinatory neuroplastogenic therapeutics targeting psychiatric and neurological disorders (search)."
Enveric's Drug Development Pipeline
Enveric Biosciences (search) is advancing a pipeline of novel neuroplastogenic small-molecule therapeutics designed to address psychiatric and neurological disorders (search). The company's lead candidate, EB-003, represents a first-in-class approach as the first known compound designed to selectively engage both 5-HT₂A and 5-HT₁B receptors to deliver fast-acting, durable antidepressant and anxiolytic effects with outpatient convenience.
Recent mechanistic data shared by Enveric demonstrated that EB-003 activates both Gq- and β-arrestin–mediated signaling downstream of the 5-HT₂A receptor (search), providing insight into its potential therapeutic mechanism.
Market Response and Future Outlook
Following the patent resolution announcement, Enveric's stock (NASDAQ: ENVB) was trading down 1.45% at $2.17 during premarket sessions. The company continues to focus on developing compounds that promote neuroplasticity without hallucinogenic effects, leveraging its differentiated drug discovery platform and growing library of protected chemical structures.
Tucker expressed confidence that "our patent portfolio will continue to generate value for our shareholders and support our efforts towards developing novel therapeutics to benefit patients with mental health conditions."