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U.S. Patent Office Issues Decision on Seagen’s Rehearing Request in Patent Dispute

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July 18, 2022

Tokyo, Japan – (July 19, 2022) – Daiichi Sankyo Co., Ltd. (TSE: 4568) (hereinafter, Daiichi Sankyo) announced today that the U.S. Patent and Trademark Office granted Seagen’s request for rehearing of the decision to institute post-grant review, and therefore decided not to proceed with the post-grant review process in which Daiichi Sankyo was contesting the patentability of certain claims within Seagen’s U.S. patent 10,808,039 (the ’039 patent). In its decision, the U.S. Patent and Trademark Office did not decide whether or not the claims of the ’039 patent are invalid.

“We are very disappointed that the U.S. Patent and Trademark Office has granted Seagen’s request after having granted Daiichi Sankyo’s rehearing request and instituting post-grant review, and Daiichi Sankyo will explore all legal options following this decision,” said Naoto Tsukaguchi, Corporate Officer and General Counsel, Daiichi Sankyo, Co., Ltd.


On December 23, 2020, Daiichi Sankyo filed a petition with the U.S. Patent and Trademark Office for post-grant review contesting the patentability of certain claims of the ’039 patent. On April 7, 2022, the U.S. Patent and Trademark Office initiated post-grant review of the ’039 patent to determine whether the claims of that patent should not have originally been granted.


About Daiichi Sankyo

Daiichi Sankyo is dedicated to creating new modalities and innovative medicines by leveraging our world-class science and technology for our purpose “to contribute to the enrichment of quality of life around the world.” In addition to our current portfolio of medicines for cancer and cardiovascular disease, Daiichi Sankyo is primarily focused on developing novel therapies for people with cancer as well as other diseases with high unmet medical needs. With more than 100 years of scientific expertise and a presence in more than 20 countries, Daiichi Sankyo and its 16,000 employees around the world draw upon a rich legacy of innovation to realize our 2030 Vision to become an “Innovative Global Healthcare Company Contributing to the Sustainable Development of Society.” For more information, please visit:



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Media Contacts:

Kim Wix
Daiichi Sankyo, Inc.
+1 973-992-6633 (office)

+81 3 6225 1126 (office)

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