More than 2.3 million people have MS worldwide, according to the National Multiple Sclerosis Society. It's thought to be caused by the immune system attacking the central nervous system, causing problems with balance, vision, speech and tremors. About 85 percent of patients have a form called relapsing-remitting MS, characterized by sporadic neurologic attacks followed by periods of remission. About one in 10 patients have PPMS, characterized by steady decline in neurological function.
Most drugs on the market now are administered by injection or infusion; more recently, the first medicines taken by pill have become available, including Biogen's Tecfidera and Novartis' Gilenya.
Roche's ocrelizumab is given by infusion once every six months, significantly less frequently than most other MS medicines. The company compared its drug with Merck KGaA's Rebif, an older therapy administered by shot three times a week.
In two studies in relapsing MS, ocrelizumab reduced patients' risk of flare-ups by almost half over two years compared with Rebif, Roche said in a statement Thursday. It also delayed progression of disability by about 40 percent and reduced brain lesions by about 80 percent, Roche said. The most common side effect was infusion-related reactions.
In PPMS, the less common form, Roche compared ocrelizumab with a placebo given the lack of approved therapies. There the medicine also met study goals, reducing the risk of disability progression over 12 weeks by 24 percent.
The medicine is Roche's first in multiple sclerosis.
UPDATED: This story was updated to include more information about MS treatments.
CORRECTION: Rebif is manufactured by Merck KGaA.