U.S. News Room

Press Releases

U.S. Patent Office Invalidates Seagen Patent in Dispute between Daiichi Sankyo and Seagen

Download the PDF version of Article

January 17, 2024

Tokyo and Basking Ridge, NJ – (January 17, 2024) – Daiichi Sankyo Co., Ltd. (TSE: 4568) (hereinafter, Daiichi Sankyo) announced today that the U.S. Patent and Trademark Office (U.S. PTO) rendered a Final Written Decision invalidating all claims of Seagen Inc.’s U.S. patent 10,808,039 (the ’039 patent) that were challenged by Daiichi Sankyo in a post-grant review proceeding (PGR).

“We are pleased that the U.S. PTO invalidated all challenged claims of the ’039 patent,” said Naoto Tsukaguchi, Corporate Officer and General Counsel, Daiichi Sankyo. 

On December 23, 2020, Daiichi Sankyo filed a PGR petition with the U.S. PTO contesting the patentability of certain claims of the ’039 patent. On April 7, 2022, the U.S. PTO granted Daiichi Sankyo’s request to institute the PGR.

The ’039 patent was the sole patent-in-suit in the infringement litigation between the parties in the U.S. District Court for the Eastern District of Texas, an appeal of which is now pending in the U.S. Court of Appeals for the Federal Circuit.

About Daiichi Sankyo
Daiichi Sankyo is an innovative global healthcare company contributing to the sustainable development of society that discovers, develops, and delivers new standards of care to enrich the quality of life around the world. With more than 120 years of experience, Daiichi Sankyo leverages its world-class science and technology to create new modalities and innovative medicines for people with cancer, cardiovascular and other diseases with high unmet medical need. For more information, please visit

Media Contacts:

Koji Ogiwara
Daiichi Sankyo Co., Ltd.
+81 3 6225 1126 (office)

Kim Wix
Daiichi Sankyo, Inc.
+1 908 992 6633

Investor Relations Contact:

Back to press releases