To make matters worse, another challenger appears to be on the way. Celgene ( CELG ) hopes to win FDA approval for promising MS drug ozanimod later this year. Mark Alles, Celgene's CEO, spoke at the J.P. Morgan Healthcare Conference on Jan. 8. It was clear in his comments that he viewed ozanimod as a disruptive force in the MS market. And the drug most in danger to lose market share from ozanimod is Tecfidera.