Shares of Forward Pharma and Acorda Therapeutics dropped Friday afternoon, after documents revealed both firms lost separate drug patent lawsuits.
Shares of Forward lost nearly 20 percent before being halted Friday around noon ET, pending the release of material news. Biogen shares closed the day up nearly 2 percent.
"We are pleased with the decision of the patent office ... and intend to defend this [drug] portfolio," a Biogen spokesperson told CNBC in a statement following Friday's news. Forward didn't immediately respond to CNBC's request for comment.