A team of Fox Rothschild attorneys led by Partner Howard S. Suh and Associate Joe Chen successfully instituted two Inter Partes Review (IPR) trials on behalf of firm client CSPC.

In the first case, CSPS Pharmaceutical Group Limited v. Ipsen Biopharm Ltd., IPR2025-00505, Paper 13 (August 14, 2025), Fox Rothschild successfully convinced the U.S. Patent and Trademark Office’s Patent Trial and Appeal Board (PTAB) that there was a reasonable likelihood based on the preliminary record that claims 1-15 of U.S. Patent No. 11,344,552 (the ’552 patent) are unpatentable based on the prior art. The ’552 patent is directed to methods of treating metastatic pancreatic cancer with liposomal irinotecan and other drugs. This decision can be read here.

In the second case, CSPC Megalith Biopharmaceutical Co. v. Shanghai Miracogen Inc., IPR2025-00685, Paper 10 (October 14, 2025), the PTAB also determined that Fox Rothschild attorneys demonstrated a reasonable likelihood of success at trial in showing that at least one claim of U.S. Patent No. 10,792,370 (the ’370 patent) is unpatentable based on the prior art. The ’370 patent is directed to antibody-drug conjugates (ADCs) comprising an anti-epidermal growth factor receptor antibody covalently linked to a cytotoxic agent via a cleavable linker. This decision can be read here.

These cases are particularly noteworthy because they also defeated Patent Owners’ previous attempts to deny the respective petitions for IPR based on discretionary denial issues. This has recently become a hot topic for PTAB practitioners because of new guidelines announced earlier this year regarding the denial of IPR petitions based on these issues.

The Fox team for the ’552 patent case included Luke Toft, Erxin Du and Kenneth MacPhail. For the ’370 patent IPR case, the Fox team included Ryan Miller, Erxin Du, Jonathan Madara, and Kenneth MacPhail.

As this article contains statements regarding past performance, please note that results may vary depending on your particular facts and legal circumstances.