Dimethyl fumarate - USA

On Sep. 16, 2020, Delaware Court found multiple sclerosis method of use patent invalid for lack of written description support under principles of collateral estoppel.

Plaintiffs (Biogen) sued many generic companies based on their filing of ANDAs seeking to market generic versions of Tecfidera®. This product is indicated for relapsing forms of Multiple Sclerosis (MS). The patent at issue here is U.S. Patent No. 8,399,514, relates to method of treatment of MS with 480 mg dose. Plaintiff sued all ANDA filers in Delaware court, except Mylan - sued in district court of West Virginia. Both the proceedings carried out on almost similar timelines.  On June 18, 2020, West Virginia court found that Mylan had proven by clear and convincing evidence that the Asserted Claims of the ’514 Patent are invalid for lack of written description. You can read the decision summary “here on this blog”.

The issue now before Delaware court was whether the judgment of invalidity rendered in the Mylan case should apply here under the principles of collateral estoppel. Delaware Court evaluated the collateral estoppel factors under Third Circuit law: (1) the identical issue was previously adjudicated, (2) that issue was actually litigated, (3) the previous determination was necessary to the decision and (4) the party being precluded from relitigating the issue was fully represented in the prior action.

Delaware court heard all the parties and weighing these factors ultimately found that collateral estoppel applies here. Thus, claims are invalid for lack of written description support.