Details in Biogen Loss to Novartis Signal Trouble for Drugmakers

Biogen Inc. failed to show it’d be irreparably harmed if Novartis AG’s Sandoz Inc. wasn’t blocked from launching its biosimilar of Tysabri while a patent-infringement suit over the blockbuster multiple sclerosis treatment continues, a redacted ruling reveals.

The recently released details of the decision suggest trouble ahead for branded biologic-drug makers looking to delay competition from cheaper alternatives.

Biogen also didn’t establish that it’s likely to prove infringement, according to Judge Gregory B. Williams’ redacted opinion, docketed Thursday in the US District Court for the District of Delaware.

Tysabri had US sales of $1.12 billion in 2022, 11% ...