This week, Enveric Biosciences announced that it has engaged “intellectual property powerhouse” Fish & Richardson to respond to a petition requesting post-grant review of its U.S. Patent No. 12,138,276.

Post-grant review (PGR) is a trial proceeding conducted before a panel of administrative judges on the Patent Trial and Appeal Board (PTAB), providing for the review of the claims in an issued patent. PGR can be requested by third parties within nine months of patent issuance to challenge the claims for failing to meet the statutory requirements for patentability, including novelty, non-obviousness, written description, and enablement.

The petition (PDF) requesting review of Enveric’s ‘276 patent was filed by Gilgamesh Pharmaceuticals on August 12, 2025. Gilgamesh’s petition seeks cancellation of 26 of Enveric’s 29 patent claims, alleging that the claimed subject matter “is either not novel or is an obvious combination of known elements for use in the treatment of psychiatric disorders,” and that the patent “lacks enabling support.”

The challenged patent, entitled Halogenated Psilocybin Derivatives and Methods of Using, issued on November 12, 2024, and has an earliest priority date of September 1, 2020.

According to Enveric’s announcement, the patent’s claims “may be relevant to Bretisilocin,” Gilgamesh’s 5-fluoro-MET candidate, which was recently acquired by AbbVie in a deal valued at up to $1.2 billion. (That transaction completed last Friday.)

Although Enveric plays coy, we note that 5-fluoro-MET is covered by the claims of the ‘276 patent, and is specifically disclosed as the compound of Formula (VII); Example 13 of Enveric’s patent also describes its synthesis and isolation, and provides characterization data…