On May 15, 2026, the Director of the U.S. Patent and Trademark Office issued summary institution decisions denying institution on the merits of two additional inter partes review (“IPR”) proceedings, IPR2026-00167 and IPR2026-00168, filed by Sarepta Therapeutics, Inc. against Genzyme relating to patents associated with gene therapy products, including Elevidys^® (delandistrogene moxeparvovec-rokl).  Earlier this month, Sarepta’s IPR2026-00149 against Genzyme’s U.S. Patent No. 12,013,326 was denied, and IPR2026-00150 against Genzyme’s U.S. Patent No. 12,031,894 was instituted (previously reported PTAB Denies Institution of One Elevidys^® IPR and Institutes Another).

In IPR2026-00167, Sarepta challenged claims 1–20 of U.S. Patent No. 11,698,377, which is directed to methods for determining the serotype of adeno-associated virus (“AAV”) particles using liquid chromatography/mass spectrometry (“LC-MS”) intact protein analysis.

In IPR2026-00168, Sarepta challenged claims 1–21 of U.S. Patent No. 12,123,880, which relates to similar LC-MS methods for analyzing and characterizing AAV particles and viral proteins.

Both patents are assigned to Genzyme. The IPRs are related to ongoing litigation between the parties, including Case No. 24-cv-00882 (D. Del.).  An additional IPR filed by Sarepta against Genzyme’s U.S. Patent No. 12,298,313 (IPR2026-00270) is awaiting an institution decision.

Sarepta reported $898.7 million in net revenue from Elevidys^® in 2025.

For more information about these and other biosimilars, please visit BiologicsHQ.

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The authors would like to thank April Breyer Menon for her contributions to this article.