Addressing subject matter eligibility in the life sciences context, the US Court of Appeals for the Federal Circuit reversed a district court’s summary judgment ruling that certain claims directed to genetically engineered host cells were patent ineligible as directed to a natural phenomenon. The Federal Circuit found that the claimed cells contained recombinant nucleic acid molecules that were markedly different from anything occurring in nature and therefore were patent eligible under 35 U.S.C. § 101. REGENXBIO Inc. v. Sarepta Therapeutics, Inc., Case No. 24-1408 (Fed. Cir. Feb. 20, 2026) (Dyk, Hughes, Stoll, JJ.)
REGENXBIO owns a patent directed to genetically engineered host cells containing a recombinant nucleic acid molecule (adeno-associated virus (AAV) rh.10 sequences). These host cells are human made and do not exist in nature. The recombinant nucleic acid molecule is created by chemically splicing together nucleic acid sequences from two different organisms. REGENXBIO sued Sarepta, alleging infringement of its patent. Both parties moved for summary judgment on whether the asserted claims were patent eligible under Section 101. The parties did not assert that claims were ineligible as an abstract idea but rather debated whether the claims disclosed natural products.
The district court analogized the claims to those considered in the 1949 Supreme Court decision in Funk Brothers Seed v. Kalo Inoculant, where two strains of bacteria from two different organisms were merely put together. The district court concluded that the invention, “taking ‘two sequences from two different organisms and put[ting] them together,’” amounted to merely packaging natural products together and found the asserted claims ineligible. REGENXBIO appealed.
The Federal Circuit reversed. Relying on the Supreme Court’s decisions in Diamond v. Chakrabarty (1980) and Association for Molecular Pathology v. Myriad Genetics (2013), the Federal Circuit explained that the relevant inquiry was whether the claimed composition as a whole possessed “markedly different characteristics” from what occurs in nature. The Court emphasized that the claimed recombinant nucleic acid molecules were not naturally occurring and cannot form in nature without human intervention. The claims required a recombinant molecule encoding both an AAV vp1 capsid protein and a heterologous sequence, created by combining genetic material from different sources.
The Federal Circuit explained that like the engineered bacterium in Chakrabarty, the claimed host cells here were “not nature’s handiwork” but a product of human ingenuity. And like the cDNA claims upheld in Myriad, the recombinant molecules represented something “distinct from” naturally occurring DNA. In contrast to Funk Brothers, where the bacteria performed exactly as they did in nature and were merely packaged together, the claimed host cells here contained a newly engineered molecule that did not exist in nature and that enabled gene therapy applications.
The Federal Circuit also noted that the claimed compositions had the potential for significant utility, specifically in gene delivery and gene therapy, further distinguishing them from the ineligible claims in Funk Brothers. Although the claims did not expressly recite a specific therapeutic use, the Court explained that potential utility may be considered in evaluating whether a composition is markedly different from naturally occurring materials.
Because the claimed host cells contained recombinant nucleic acid molecules that were markedly different from naturally occurring products, the Federal Circuit held that the claims were not directed to a natural phenomenon at step one. Having resolved eligibility at step one, the Court did not proceed to step two of the Alice framework.
Practice note: This decision reinforces that genetically engineered compositions, particularly those involving recombinant nucleic acids created through human intervention, may qualify as patent-eligible subject matter when they are structurally and functionally distinct from anything found in nature.
