U.S. regulators have approved the first drug for an aggressive type of multiple sclerosis, giving a lift to patients with a form of the disease that until now had no approved treatment. Although there are more than a dozen treatments for the most common form of MS, drugmaker Roche Group’s ocrelizumab (with the brand name Ocrevus) is the first FDA-approved medicine for the primary progressive form of the neurological disease (PPMS).