AbbVie is facing a potential legal challenge from Enveric Biosciences (NASDAQ: ENVB) regarding its recently acquired major depressive disorder candidate, bretisilocin. Enveric alleges that bretisilocin, which AbbVie agreed to acquire from Gilgamesh Pharmaceuticals in a deal worth up to $1.2 billion, infringes on its U.S. Patent No. 12,138,276 for 'Halogenated psilocybin derivatives and methods of using.' [8, 7] Enveric has retained the law firm Fish and Richardson to defend its patent against a Post-Grant Review filed by Gilgamesh and stated its intent to 'vigorously defend its intellectual property.' [8] The news caused a significant reaction in Enveric's stock, which saw an approximate 20% increase in morning trading. [8]