On September 18 and 19, 2025, the Patent Trial and Appeals Board (“PTAB”) issued final written decisions for four inter partes review (“IPR”) challenges brought by Merck Sharp & Dohme LLC (“Merck”) against Johns Hopkins University’s (“Johns Hopkins”) pembrolizumab patents, finding that all claims were unpatentable. The dispute between Merck and Johns Hopkins concerns a family of patents assigned to Johns Hopkins that Merck alleges originated as part of a research collaboration between the parties to study the effectiveness of Merck’s KEYTRUDA (pembrolizumab) on tumors that carry a high mutational load. In a district court litigation related to the dispute, Johns Hopkins counters that “[t]he concept for the groundbreaking clinical study developed by Hopkins researchers was . . . prepared before there was any agreement between Hopkins and Merck, and the contributions Merck alleges to have made to the study protocol were known, trivial and have never been claimed as inventions by the Hopkins Inventors.”
As we previously reported, one of the IPRs, IPR2024-00625 (U.S. Patent No. 11,339,219), was instituted on September 23, 2024, and three, IPR2024-00647 (U.S. Patent No. 11,649,287), IPR2024-00649 (U.S. Patent No. 11,629,187), and IPR2024-00650 (U.S. Patent No. 11,634,491) were instituted on September 27, 2024. All four concern patents directed toward the use of pembrolizumab in treating and reducing the risk of progression of colorectal cancer and various types of solid tumors following positive diagnostic testing for microsatellite instability high (“MSI-H”) or mismatch repair deficiency (“dMMR”). These IPRs are four of nine that were filed by Merck to challenge patents at issue in the district court litigation Merck Sharp & Dohme LLC v. The Johns Hopkins University, 1:22-cv-03059-JRR (D. Md.). All nine were instituted and the district litigation was stayed. A final written decision for the first IPR filed, IPR2024-00240 (U.S. Patent No. 11,591,393), issued on June 9, 2025 and found all 42 claims unpatentable.
As in IPR2024-00240, all claims of the patents at issue in IPR2024-00625, IPR2024-00647, IPR2024-00649, and IPR2024-00650 were found unpatentable over prior art that includes the study record of Johns Hopkins’s Phase 2 clinical trial examining the effectiveness of KEYTRUDA in patients with MSI-H or dMMR cancer.
Four of the nine IPRs remain pending and the one-year final written decision deadline has been extended for each under 37 C.F.R. § 42.100(c). The deadline for IPR2024-00622 (U.S. Patent No. 10,934,356), IPR2024-00623 (U.S. Patent No. 11,325,974), and IPR2024-00624 (U.S. Patent No. 11,325,975), originally September 23, 2025, has been extended to November 7, 2025, and the deadline for IPR2024-00648 (U.S. Patent No. 11,643,462), originally October 3, 2025, has been extended to November 18, 2025.
Stay tuned to Big Molecule Watch for more updates on the pending IPRs and related litigation.