Spotlight on Upcoming Oral Arguments – October 2025

The following arguments will be available live to the public, both in-person and through online audio streaming. Access information will be available by 9 AM ET each day of argument at: https://cafc.uscourts.gov/home/oral-argument/listen-to-oral-arguments/.

Tuesday, October 7, 2025, 10:00 A.M.

Regenxbio Inc. v. Sarepta Therapeutics, Inc., No. 2024-1408, Boston, MA, Panel C

This appeal arises from the district court’s grant of summary judgment finding that Regenxbio’s U.S. Patent No. 10,526,617 was invalid for claiming patent-ineligible subject matter under 35 U.S.C. § 101. The ’617 patent claims a host cell containing a recombinant nucleic acid molecule, which is a combination of a naturally occurring adeno-associated virus (AAV) sequence and a non-AAV sequence. The district court found that the claimed host cells are not “markedly different” from their naturally occurring components, and that they are directed to a natural product without an inventive concept under the Alice/Mayo test. The court thus found the claims patent ineligible. Regenxbio appealed.

On appeal, Regenxbio argues that the patent-eligibility analysis for natural-product-based compositions should focus on whether they are “markedly different” from natural products, but that the district court erred in its “markedly different” analysis. According to Regenxbio, the claimed host cell is a novel, human-made composition that differs from natural products both structurally and functionally. Structurally, Regenxbio argues that the claimed host cells are not natural and can only be made by genetic engineering. Functionally, Regenxbio contends that the host cells can be used in several applications (such as bacterial-host-cell cloning and gene therapy) in which natural cells cannot be used. According to Regenxbio, these differences also show that the claims are not directed to any natural product under the Alice/Mayo test.

Sarepta counters that the district court correctly found Regenxbio’s claims ineligible under both the “markedly different” test and the Alice/Mayo test. Under the “markedly different” test, Sarepta argues that (1) the structural differences Regenxbio asserted result from isolating naturally occurring AAV sequences, which do not constitute “markedly different characteristics”; and (2) because they are not claim requirements, the claimed host cells may or may not have the functions Regenxbio identified, so those functions are not “defining features” of the claims and are irrelevant for eligibility. Sarepta contends that the claims cover combinations of two naturally occurring sequences, which cannot support eligibility. Additionally, Sarepta argues that the claims fail under the Alice/Mayo test because they are directed to natural AAV sequences and recite nothing new or inventive.  

The Federal Circuit’s decision may provide helpful clarification on the patent eligibility analysis, particularly for inventions relating to genetic engineering.

Tuesday, October 7, 2025, 10:00 A.M.

Canatex Completion Solutions, Inc. v. Wellmatics, LLC, No. 24-1466, Newton, MA, Panel D

This case addresses the extent to which a court can correct claim language errors during litigation. Canatex sued Wellmatics for infringing its U.S. Patent No. 10,794,122, related to tools used to release perforating guns in oil and gas wells. In connection with the parties’ claim construction disputes, Canatex requested the court to judicially correct the claim phrase “the connection profile of the second part” to recite “the connection profile of the first part.” The court denied the request. It explained that it may only correct errors that are evident on the face of the patent, that the correction is not subject to reasonable debate, and that the prosecution history does not suggest a different interpretation. Here, the court found that the error was not “evident,” and it could have been intended to mean “a connection profile of the second part.” The court also noted that Canatex’s failure to seek PTO correction further suggested the error was not evident. The court subsequently found the claims invalid as indefinite. Canatex appealed.

On appeal, Canatex raises various arguments challenging the district court’s ruling. Among other arguments, Canatex contends that the district court (1) erred in finding Canatex’s election to pursue judicial correction as opposed to PTO correction suggests the error was not evident; (2) conflated the “evident” inquiry with the later “reasonable debate” inquiry; and (3) viewed the error out of context. According to Canatex, the surrounding claim language and the specification show that the error is obvious, and the district court’s alternative correction for the language to mean “a connection profile of the second part” is unreasonable and cannot be reconciled with “basic principles of operation.”

Wellmatics maintains that the district court properly denied Canatex’s request because the request failed to meet several requirements for judicial correction. First, Wellmatics contends that the error is not a minor clerical error; instead, it is a major error pervasive enough throughout the patent that it could have been an intentional choice. Wellmatics asserts that Canatex has also proffered different meanings of the term during the litigation, which indicates that the error is not obvious. But even if the error was obvious, continues Wellmatics, the correction is subject to reasonable debate because alternative corrections are possible. To Wellmatics, judicial correction is improper, and any correction is a matter for the PTO (which Canatex sought after filing the appeal).