Federal Circuit Revives Regenxbio Patent Suit Against Sarepta Over DMD Gene Therapy
A U.S. appeals court revived Regenxbio’s patent suit against Sarepta, holding the asserted gene-therapy host cell claims are markedly different from anything occurring in nature.
The U.S. Court of Appeals for the Federal Circuit revived Regenxbio and the University of Pennsylvania's patent lawsuit against Sarepta Therapeutics after reversing a ruling that had invalidated the patent at issue. The court held that the patent covers genetically engineered cells with a molecule that is "markedly different from anything occurring in nature" and reversed a district court’s summary judgment that the claims were patent ineligible under 35 U.S.C. § 101.
The asserted claims are directed to cultured host cells containing a recombinant nucleic acid molecule encoding an AAV vp1 capsid protein and a heterologous non-AAV sequence. The recombinant nucleic acid was created in the lab by splicing together genetic material from two different organisms and then introducing that combined molecule into the cell. The Federal Circuit held that the claimed host cells contain a recombinant nucleic acid molecule that does not and cannot exist in nature and therefore are not directed to ineligible naturally occurring subject matter.
The district court had determined that the patent was invalid because it covers naturally occurring DNA sequences and that the claims merely combined two natural components and put them in a host cell. On appeal, the Federal Circuit followed Diamond v. Chakrabarty and concluded that the claimed cultured host cells have markedly different characteristics and the potential for significant utility from what is naturally occurring. The court contrasted the claims with Funk Brothers and certain claims in Myriad, reasoning that the recombinant nucleic acid is "not nature’s handiwork" and "could not form in nature on its own" because it joins genetic material from different species into a single molecule.
The patent dispute concerns gene-therapy technology related to Duchenne muscular dystrophy. Sarepta’s Elevidys, the first gene therapy for DMD, received U.S. Food and Drug Administration approval in 2023 and earned $898.7 million in revenue in 2025, according to a company report. Regenxbio is developing its own DMD treatment, and its 2020 lawsuit alleged that Elevidys infringed a gene-therapy patent licensed from the University of Pennsylvania.
Regenxbio and the University of Pennsylvania have requested more than $900 million in damages, according to a court transcript. The case is Regenxbio Inc v. Sarepta Therapeutics Inc., No. 24-1408, in the U.S. Court of Appeals for the Federal Circuit.