A federal jury sided with Serono and Pfizer, finding that Biogen’s patent for Avonex was invalid.

In its verdict, the jury invalidated a key Biogen patent on the multiple sclerosis drug, covering methods of developing proteins that work similarly to the interferons used in the manufacture of Avonex. Biogen has been in court alleging infringement claims since 2010 by companies including Pfizer, Bayer, EMD Serono and Novartis.

In the Feb. 23 verdict in the District of New Jersey, a jury found that there was prior knowledge of interferons’ utility in treating several medical conditions before Biogen was issued the patent.