Biogen loses bid to reverse loss in Mylan MS drug patent dispute

(Reuters) - A U.S. appeals court on Tuesday upheld generic drugmaker Mylan's successful challenge to a patent covering Biogen's top-selling multiple-sclerosis treatment, finding the patent didn't sufficiently describe its method for treating the neurological disease.

In a split decision, the U.S. Court of Appeals for the Federal Circuit affirmed a West Virginia federal court's ruling that the relevant parts of the patent were invalid, which had helped clear the way for Mylan to launch its generic version of Biogen's Tecfidera.

Tecfidera is Cambridge, Massachusetts-based Biogen's best-selling drug, but Biogen's revenues from it and related drug Vumerity dropped from over $4.4 billion to $3.9 billion in 2020 after generic competitors entered the market.

A Biogen spokesperson said the company was disappointed in the decision. Mylan's attorney David Anstaett of Perkins Coie didn't immediately respond to a request for comment, nor did Viatris.

Biogen sued Mylan, now part of Viatris, in West Virginia in 2017, alleging Mylan's proposed generic of Tecfidera would infringe its patents.

U.S. District Judge Irene Keeley ruled last year that a key Biogen patent was invalid because it didn't describe its method for treating MS clearly enough. Biogen appealed to the Federal Circuit, which rejected its bid to halt Mylan's sale of the generic during the appeal.

U.S. Circuit Judge Jimmie Reyna affirmed Keeley's decision Tuesday, finding the relevant parts of the patent weren't supported by the patent's written description of the invention.

Reyna said the description's "single passing reference" to Biogen's claimed method of using a specific dosage of Tecfidera to treat MS wasn't enough to inform a skilled artisan that it would work effectively.

Circuit Judge Todd Hughes joined Reyna in the majority opinion.

In a dissent, Circuit Judge Kathleen O'Malley said the majority wrongly focused on the patent's failure to describe the treatment's "clinical efficacy," which involves "the type of scientific rigor associated with Phase III clinical trials," when the relevant parts of the patent only required "therapeutic effects."

William Lee of Wilmer Cutler Pickering Hale & Dorr and James Monroe and Paul Browning of Finnegan Henderson Farabow Garrett & Dunner represented Biogen.

The case is Biogen International GmbH v. Mylan Pharmaceuticals Inc, U.S. Court of Appeals for the Federal Circuit, No. 20-1933.

For Biogen: William Lee of Wilmer Cutler Pickering Hale & Dorr, James Monroe and Paul Browning of Finnegan Henderson Farabow Garrett & Dunner

For Mylan: David Anstaett of Perkins Coie

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