Daiichi Sankyo gets US patent office to restart review of Seagen patent
Daiichi Sankyo is going back after Seagen in the latest bout of patent infringement accusations.
The Japanese pharma announced Friday that the US Patent and Trademark Office (PTO) has agreed to the company’s request to restart a post-grant review of a Seagen patent.
A post-grant review (PGR) is when the patent office’s board — called the Patent Trial and Appeal Board — examines at least one claim from an existing patent in a bid to determine if that claim is capable of being patented.
The patent in question, no. 10,808,039, covers certain mechanics of antibody-drug conjugates, a sweet spot of the Seattle biotech.
According to Daiichi’s statement, the Japanese pharma filed with the US Patent and Trade office in Dec. 2020 asking for a post-grant review as it was looking to contest the “patentability of certain claims of the ‘039 patent.” The patent office started the initial post-grant review in April 2022.
Three months later, the office re-heard the decision to grant Daiichi’s review per Seagen’s request — later shutting down the post-grant review. Finally, the original PGR panel was instructed on Feb. 7 to decide whether or not to restart the panel.
“We are very pleased that the PGR will be reinstituted given the PTO’s determination that our petition presented compelling evidence of unpatentability of the ’039 patent,” Daiichi general counsel Naoto Tsukaguchi said in a statement.
The row is centered around Enhertu, the blockbuster oncology ADC at the heart of a 2019 collab that saw AstraZeneca pay $1.35 billion upfront to Daiichi to partner on. The therapy was first approved by FDA later that year, with its most recent approval in August of 2022.
Daiichi lost a court verdict related to Enhertu earlier last year, when a Texas jury found Daiichi guilty of infringing on Seagen’s ‘039 patent, dating back to 2005 and involving Seagen’s protease-cleavable linkers. Four months later, an appeal from Daiichi to push back a $42 million fine failed in federal court.
Daiichi said after the failed appeal that it would continue to contest the ruling, including a detail that Seagen could be awarded royalties from Enhertu.
Editor’s note: This story has been corrected to reflect a change in the story. Enhertu was first approved in 2019. Endpoints regrets the error.