An appellate court has ruled in favor of REGENXBIO in its patent dispute with Sarepta Therapeutics regarding technology used in a gene therapy for Duchenne muscular dystrophy. The decision, issued by Judge Kara Stoll, reverses a previous lower court ruling from January 2024 that had invalidated REGENXBIO’s patent on the grounds that its elements were naturally occurring.
“The claims here are not merely directed to repackaging products of nature,” Judge Stoll wrote in her Friday ruling. She further stated that REGENXBIO’s technology “fundamentally [creates] a cell containing a molecule that could not form in nature on its own.” Stoll criticized the earlier decision, saying it “takes too narrow a view of the asserted claims by focusing on whether the individual components of the claim were markedly different from what is naturally occurring and failing to consider whether the claimed composition as a whole was ‘not naturally occurring.’”
The lawsuit was filed by REGENXBIO and the University of Pennsylvania, which owns and licenses the contested patent, in September 2020. They alleged Sarepta used their adeno-associated virus (AAV) vector platform in developing Elevidys, which received approval for Duchenne muscular dystrophy treatment in June 2023.
In January 2024, a Delaware district court sided with Sarepta, finding that REGENXBIO’s patents were invalid because they consisted of unaltered natural components. This made them unpatentable under U.S. law.
Judge Stoll’s appellate decision now sends the case back to the lower court for reconsideration. “We have considered Sarepta’s remaining arguments and find them unpersuasive,” she wrote.
This legal outcome follows several challenges for REGENXBIO this year. Earlier this month, the FDA rejected its Hunter syndrome gene therapy after extending review by three months due to concerns about using natural history controls in RGX-121’s pivotal study. In January, regulators placed a clinical hold on REGENXBIO’s Hurler syndrome gene therapy following a patient developing a tumor; this hold also affected RGX-121.
Sarepta has also faced difficulties related to Elevidys. Two deaths linked to Elevidys led Sarepta to shift focus from gene therapy to an siRNA-based pipeline last year. The FDA subsequently added a black box warning and limited eligible patients for Elevidys.
