On September 25, 2026, the Patent Trial and Appeal Board (“PTAB”) issued Final Written Decisions (“FWD”) in PGR2025-00033 and PGR2025-00039 finding all remaining challenged claims of Halozyme’s U.S. Patent Nos. 12,049,652 (“the ’652 patent”) and 12,104,185 (“the ’185 patent”) unpatentable. On October 1, 2026, the PTAB issued a FWD in PGR2025-00052 finding all challenged claims of Halozyme’s U.S. Patent No. 12,264,345 (“the ’345 patent”) unpatentable. On October 2, 2026, the PTAB issued a FWD in PGR2025-00046 finding all remaining challenged claims of Halozyme’s U.S. Patent No. 12,091,692 (“the ’692 patent”) unpatentable. The Halozyme patents were challenged by Merck and are part of the broader dispute between Merck and Halozyme relating to Keytruda Qlex™ (pembrolizumab; berahyaluronidase alfa-pmph) and Halozyme’s PH20 hyaluronidase patent portfolio.
The ’652, ’185, ’345, and ’692 patents are directed to modified PH20 hyaluronidase polypeptides, including modified polypeptides that exhibit increased stability and/or increased activity. As in prior FWDs involving related Halozyme PH20 patents (previously reported Keytruda Qlex™ Updates: Final Written Decisions Find Two Halozyme PH20 Patents Unpatentable While Institution is Denied for Third Patent; Keytruda Qlex™ Updates: PTAB Finds Additional Halozyme PH20 Patent Unpatentable in Final Written Decision; Keytruda Qlex™ Updates: PTAB Finds Halozyme ’520 PH20 Patent Unpatentable and Institutes Three IPRs), the Board found that the term “modified PH20 polypeptide” required hyaluronidase activity and applied similar written-description and enablement reasoning to the challenged claims.
In each FWD, the Board found the challenged claims unpatentable under 35 U.S.C. §112(a) for lack of written description and enablement. Similar to the Board’s reasoning in prior FWDs involving related Halozyme PH20 patents, the Board found that the patents’ single-substitution data and limited disclosure regarding multiply modified PH20 polypeptides did not sufficiently describe or enable the full scope of the challenged claims.
Separately, Halozyme has filed appeals from earlier FWDs involving related PH20 patents, including PGR2025-00003, PGR2025-00004, PGR2025-00006, and PGR2025-00009. The appeals have been docketed as Case Nos. 26-2299, 26-2300, 26-2302, and 26-2303, respectively.
Keytruda Qlex™ was approved in September 2025 and generated approximately $40 million in 2025 sales, including approximately $35 million in the fourth quarter of 2025.
For more information about these and other biologic drug patent disputes, please visit BiologicsHQ.
_____________________________________________________
The authors would like to thank April Breyer Menon for her contributions to this article.
