The launch of Ocrevus will enable Roche to enter the lucrative MS market and will help Roche to diversify its existing drug portfolio, which is largely focused on immuno-oncology. Ocrevus is the first and only approved drug for the treatment of PPMS, addressing an important unmet need in MS. As such, the drug is already expected to see rapid uptake and reach blockbuster status, and ultimately pose fierce competition for the leading company in MS, Biogen. Biogen co-developed Ocrevus with Roche and will receive tiered royalty payments on US sales. However, the net effect of Ocrevus on sales for Biogen remains to be seen.