Daiichi to pay $41.9M to Seagan over patent dispute

April 12, 2022

Daiichi Sankyo and Seagan, formerly Seattle Genetics, are still hashing out their patent dispute over Daiichi’s breast cancer drug. 

 A Texas federal jury ruled that Daiichi’s blockbuster drug Enhertu infringes on a patent held by Seagan. Now, Daiichi must pay $41,820,000 in royalty revenue to U.S. biotech Saegan.

Seagan has also asked for the court to issue an order requiring Daiichi to make royalty payments for future sales of Enhertu until Seagan’s original patent expires in November 2024. The court has not yet made a ruling on Seagan’s request.

Naoto Tsukaguchi, corporate officer and general counsel at Daiichi, said the company disagreed with the jury verdict and is “committed to defending its rights.” The Japanese pharma heavyweight will look into ways to push back, including “post-trial motions and an appeal.”

Daiichi and Seagan have been wrapped up in legal battles since October 2019, when Seagan filed a complaint against Daiichi saying that the Japanese company had infringed on Saegan’s ‘039 patent of certain antibody drug conjugates. Then, in December, Daiichi asked the U.S. Patent Office to review the original patent decision and certain claims. The board has agreed to start a review on Seagan’s ‘039 patent.

Enhertu is being developed via a collaboration between Daiichi and AstraZeneca. The two signed the multi-billion dollar agreement in April 2019, with  AstraZeneca paying Daiichi Sankyo an upfront payment of $1.35 billion, with contingent payments of up to $5.55 billion and $1.75 billion for sales-related milestones, in return for shared rights to sell and develop the drug. The exception is in Japan, where Daiichi will have exclusive rights.