On 9 June 2025, the US Patent Trial and Appeal Board issued a written decision invalidating all claims of Johns Hopkins University’s US Patent No. 11,591,393 on the basis of anticipation and obviousness. US Patent No. 11,591,393 is directed to treating patients with microsatellite instable (MSI) or DNA mismatch repair deficient (dMMR) colorectal cancer with pembrolizumab. The decision was issued in proceedings for inter partes review (IPR) filed by MSD on 20 November 2021 (IPR2024-240).
The following IPRs commenced by MSD in relation to Johns Hopkins University (JHU) patents relating to pembrolizumab remain pending:
- 11,649,287 (IPR2024-00647), 11,629,187 (IPR2024-00649), and 11,634,491 (IPR2024-00650): petitions filed on 13 March 2024, IPRs instituted on 27 September 2024;
- 10,934,356 (IPR2024-00622), 11,325,974 (IPR2024-00623), 11,325,975 (IPR2024-00624) and 11,339,219 (IPR2024-00625): petitions filed on 4 March 2024, IPRs instituted on 23 September 2024;
- 11,591,393 (IPR2024-240): petition filed on 30 November 2023, IPR instituted 13 June 2024; and
- 11,643,462 (IPR2024-00648): petition filed 13 March 2024, IPR instituted 3 October 2024.
In November 2022, MSD filed a complaint in the United States District Court (District of Maryland) against JHU seeking declarations of breach of contract, non-infringement and promissory estoppel. Based on the complaint, the dispute arose out of a contract between MSD and the University to design and conduct a clinical trial on administration regimes for Keytruda® (pembrolizumab) in cancer patients with certain genetic biomarkers. JHU filed a counter-claim on 12 April 2023, including alleging infringement of each of the patents subject to the IPR proceedings referred to above. The US Court proceeding has been stayed pending the outcome of the IPRs. No trial date has been scheduled.