Mylan Inc. and Momenta Pharmaceuticals Inc. could start selling their versions of the drug on May 25, after the remaining patents on the drug expire. Teva Pharmaceutical Industries Ltd., which makes Copaxone, said the US Court of Appeals for the Federal Circuit overturned a total of five patents on the drug and said it was disappointed with the decision. Teva plans to appeal the ruling.
The generics have not yet received Food and Drug Administration approval.
The Israeli drug maker said sales of Copaxone grew 17% to $1.06 billion in the first quarter. US sales rose 31% to $806 million over that period. Teva is the world's biggest maker of generic drugs, and it reported $4.9 billion in revenue in the first quarter.
Teva sued Mylan and Momenta, along with its partner Sandoz, for infringing on the patents supporting the drug. A US District Court ruled in Teva's favor and upheld the patents in June 2012.
Barclays analyst Douglas Tsao said Copaxone already appeared to be losing market share to a newer drug, Biogen Idec Inc.'s Tecfidera, and the ruling allowed the generics to reach the market 18 months earlier than Teva had hoped. However, he said the court's decision did not change the overall picture for Teva.
"Investors have generally viewed Copaxone as a declining asset and, worst case, this merely speeds up that decline," he wrote. Tsao said Teva's business model was in transition and it was not clear what path the company would take. He rated the shares "equal weight."