The company’s mainstay drugs are treatments for multiple sclerosis, a group under increased threat since Roche Holding entered the market last month with Ocrevus. Though Biogen is entitled to a share of Ocrevus sales through a royalty agreement, analysts worry that may not be enough to make up for its loss of market share and diminished ability to raise prices. Ocrevus is most likely to hit sales of Biogen’s drug Tysabri, Chief Financial Officer Paul Clancy said on a conference call, and could also hurt sales of the company’s top drug, the multiple sclerosis pill Tecfidera. Biogen’s multiple sclerosis drugs bested expectations for the quarter, helped by $545 million in sales of the Tysabri injection that beat analysts’ average estimate of $481 million. The CEO has promised to boost sales by focusing on Spinraza and creating ways to keep patients on the company’s lead product, Tecfidera. Spinraza, developed in partnership with Ionis Pharmaceuticals Inc., has proved an unexpected windfall to Biogen, dashing from late-stage trials to U.S.