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Are genetically engineered molecules patentable?
The U.S. Court of Appeals for the Federal Circuit issued an important ruling for the life sciences industry on 20 February 2026. The court considered the patent eligibility of certain genetically engineered compositions; namely, cultured cells containing recombinant nucleic acids.
Many rulings regarding patent eligibility center on whether the patented invention is directed to an ineligible abstract idea. The appellate court in this case, however, weighed whether the compositions were ineligible natural phenomena. The case further differentiates from the Funk Brothers analysis and provides an additional example of claims that are §101 eligible as “something more” as first articulated in Chakrabarty.
At the cellular level
REGENXBIO Inc. owns a patent on genetically engineered (human-made) host cells that contain recombinant nucleic acid molecules with adeno-associated virus (AAV) sequences. Recombinant nucleic acid molecules are created by chemically splicing together nucleic acid sequences from two different sources. AAVs are a type of virus with single-stranded DNA. AAVs can be used to transfer genes into human cells, helping to treat or cure genetic disorders.
REGENXBIO sued Sarepta Therapeutics Inc. for patent infringement. The lawsuit was based on Sarepta’s use of an AAV variant in cultured host cells to make a gene therapy product to treat a type of muscular dystrophy. The trial court dismissed the case before trial, finding the patented host cells were a natural phenomenon and therefore ineligible for patent protection. REGENXBIO appealed to the Federal Circuit, which hears all appeals in patent cases.
Under the microscope
The court focused on whether the host cells, compared with that which is naturally occurring, have “markedly different characteristics,” and “the potential for significant utility.” It began by noting that the parties didn’t dispute that the host cells included a recombinant nucleic acid molecule that cannot exist in nature because it must be spliced together via human intervention from at least two different sources to satisfy the requirements laid out in the patent.
Although the molecules contained naturally occurring DNA segments, the court said, they weren’t “nature’s handiwork” or a previously unknown natural phenomenon. Rather, they were a “nonnaturally occurring manufacture or composition of matter.” A lab technician unquestionably creates something new by splicing together the recombinant nucleic acid molecule with the AAV and a heterologous (meaning from a different source) non-AAV sequence (the gene to be delivered) and inserting the molecule into the host cell. And that new cell, the court said, couldn’t form in nature on its own.
The appellate court faulted the analysis of the trial court as too narrow. It said the lower court erred by focusing (similar to Funk Brothers) on whether the individual components of the patent claim were markedly different from those that occur naturally. The proper inquiry is whether the patented composition as a whole is markedly different from what occurs in nature.
The Federal Circuit then turned to the question of utility. It was undisputed, the court said, that the patented composition had the “potential for significant utility.” Various embodiments of as claimed were beneficial for gene delivery to selected host cells and, in turn, gene therapy patients. It was irrelevant, the court added, that the potential for significant utility was only implicit.
Nature vs. nurture
The opinion in this case sheds valuable light on how the CAFC will evaluate the patent eligibility of genetically engineered biotechnology inventions. Those inventions that don’t merely repackage products of nature — here, host cells that contain molecules “markedly different” from anything naturally occurring — should survive the eligibility analysis.
Subsequent PTAB Application
Following the issuance of the CAFC decision, the Patent Trial and Appeals Board on 04 August 2026 issued their decision in Ex parte Frank C. Marini and Shay Soker (2026 Pat. App. LEXIS 3276). The PTAB addressed the rejection by the Examiner of record under 35 U.S.C. §101 of claims directed to a model system of liver fibrosis and a method of making and using the same. Citing REGENXBIO in contact with Chakrabarty (Diamond v. Chakrabarty, 447 U.S. 303, 310 (1980)) and Funk Brothers (Funk Brothers [Seed Co. v. Kalo Inoculant Co., 333 U.S. 127, 68 S. Ct. 440, 92L. Ed. 588, 1948 Dec. Comm'r Pat. 671(1948)).
The Examiner forwarded the contention that the liver organoids in question were simply no more than agglomerations of naturally occurring components (e.g., liver cells, extracellular matrix). Arguing, essentially, that since each component is individually natural, the combination is therefore ineligible.
In reversing the Examiner the PTAB noted that the supposition forwarded by the Examiner was “the same analytical error…corrected in REGENXBIO” and further articulated that there are clear, non-natural, structural and compositional differences between the claimed organoids and native liver tissue.
In summation, the line of cases clarifies and extends the core principle that one can obtain a patent directed to a non-natural end result despite using wholly-natural components; the caveat remains unchanged that the sum, the newly taught and claimed disclosure, must be more than that of the individual components.
© 2026
