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Daiichi Sankyo Provides Update on Patent Dispute with Seagen

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April 08, 2022

Tokyo and Basking Ridge, NJ – (April 8, 2022) – Daiichi Sankyo Co., Ltd. (TSE: 4568) announced today that a jury in the U.S. District Court of Eastern District of Texas decided that ENHERTU® infringes Seagen’s US patent 10,808,039 (the ’039 patent). However, on April 7, 2022, the U.S. Patent Office initiated post-grant review of the ’039 patent to determine whether the claims of that patent should not have originally been granted.

Discovered by Daiichi Sankyo, ENHERTU® is being co-developed and co-commercialized by Daiichi Sankyo and AstraZeneca.

“Daiichi Sankyo disagrees with the jury verdict, is committed to defending its rights, and will explore options with respect to the jury verdict, including post-trial motions and an appeal,” said Naoto Tsukaguchi, Corporate Officer and General Counsel, Daiichi Sankyo Co., Ltd. “We are pleased that the U.S. Patent Office has agreed to review their initial granting of the ’039 patent.”

The jury awarded Seagen $41,820,000 in damages for the period leading up to trial and found that there was willful infringement of the ’039 patent. Seagen has also requested the Court to issue an order requiring the payment of royalties on future sales of ENHERTU® until the expiration of the ’039 patent in 2024. The court has not yet ruled on Seagen’s request for royalties on future sales and whether to enhance damages in view of the jury finding of willful infringement.

On October 19, 2020, Seagen filed a complaint against Daiichi Sankyo Co., Ltd. in the U.S. District Court for the Eastern District of Texas alleging infringement of the ’039 patent covering certain antibody drug conjugates. On December 23, 2020, Daiichi Sankyo filed a petition with the U.S. Patent Office for post-grant review contesting the patentability of certain claims within the ’039 patent.

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:

Media Contacts:

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

Masashi Kawase
Daiichi Sankyo Co., Ltd.
+81 3 6225 1126 (office)

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