Roche said on Wednesday its Ocrevus multiple sclerosis drug controlled the most common form of the disease better than a rival's medicine and worked against another form of MS for which there is no approved treatment.

A 75 percent higher proportion of relapsing-remitting multiple sclerosis patients reached "no evidence of disease activity" status with Ocrevus in a head-to-head trial against Merck's Rebif, Roche said in a statement.

Additionally, doctors found no evidence of disease progression in a 47 percent higher proportion of primary progressive multiple sclerosis (PPMS) patients compared with a placebo. There are no approved treatments for PPMS.

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Earlier this year, Roche accelerated its timeline for Ocrevus approval, saying it could come in 2016 after the U.S. Food and Drug Administration gave it fast-track review status.

Analysts estimate Ocrevus, whose generic name is ocrelizumab, could generate annual sales of nearly 4 billion Swiss francs ($4.09 billion) by 2022, according to Thomson Reuters data.

"These new data suggest that ocrelizumab consistently impacts disease progression and has the potential to change how we approach treating both relapsing and primary progressive MS," Gavin Giovannoni, who heads up neurology at The London School of Medicine and Dentistry and is on the committee leading the Roche study, said in the statement.

Ocrevus is among several new drugs that Roche hopes can offset patent expiries among older medicines that will leave it more vulnerable to competition from cheaper generic or biosimilar medicines.

About 85 percent of those diagnosed with MS suffer from relapsing-remitting MS, while 10 percent suffer from primary-progressive MS.

Roche is presenting more detailed findings from the Ocrevus studies, called Opera I and Opera II, at an MS conference in London this week.

($1 = 0.9769 Swiss francs)