By Blake Brittain
WASHINGTON (Reuters) -The U.S. Supreme Court on Monday declined to hear Biogen Inc's bid to win reinstatement of a patent on the company's blockbuster multiple sclerosis drug Tecfidera in a dispute with Viatris Inc subsidiary Mylan Pharmaceuticals Inc.
The justices turned away Biogen's appeal of a lower court's decision to invalidate the patent in a ruling that helped clear the way for Mylan's generic version of Tecfidera.
Biogen sued Mylan, now part of Canonsburg, Pennsylvania-based Viatris, in West Virginia in 2017, saying Mylan's proposed generic version of Tecfidera would infringe Biogen patents. U.S. District Judge Irene Keeley ruled in 2020 that a key Tecfidera patent was invalid. Mylan launched its generic that August.
Tecfidera is still one of Cambridge, Massachusetts-based Biogen's best-selling drugs. But the company's revenues from it have dropped because of generic competition.
The patent-focused U.S. Court of Appeals for the Federal Circuit upheld the judge's ruling in favor of Mylan in a 2-1 decision, finding the patent's written description did not outline its method for treating MS clearly enough.
The Federal Circuit decided 7-3 not to have all of its judges hear the appeal after the three-judge panel's ruling.
Biogen told the Supreme Court that the Federal Circuit had added "additional, atextual requirements that distort" the standard for securing a patent involving a clear written description of the invention and how it is made and used. Biogen also said the decision would "chill investment in innovative technologies, including life-altering medical treatment."
Mylan responded that the relevant part of Biogen's patent failed to describe its method for treating MS with specificity "even once."
(Reporting by Blake Brittain; Editing by Will Dunham)