By Ben Hirschler
Oct 8 (Reuters) - Roche's big new drug hope ocrelizumab cut multiple sclerosis relapses by nearly 50 percent compared with the older product Rebif in two large clinical trials, underscoring its potential in the main relapsing form of the disease.
Ocrelizumab also cut clinical disability by nearly a quarter in a separate study of patients with primary progressive multiple sclerosis (PPMS), which affects around 15 percent of patients and for which there is currently no approved treatment.
The Swiss company had previously said its new drug worked in both settings but the scale of effect is only being disclosed this week at the European Committee for Treatment and Research in Multiple Sclerosis congress in Barcelona.
Roche believes ocrelizumab's potency and benign side effect profile make it unique, while industry analysts see it as a likely multibillion-dollar-a-year seller that will help the group diversify beyond its mainstay cancer business.
In the two relapsing MS trials, the new drug reduced the annualised relapse rate by 46 and 47 percent compared to Merck KGaA's Rebif, while the rate of confirmed disability progression (CDP) was 37 and 43 percent lower.
Rebif, an interferon drug, already reduces the number of relapses by around a third.
"On relapses, we are essentially equal to the most efficacious medicines out there and on CDP we believe we are a little bit better," Roche's head of neuroscience clinical development Paulo Fontoura told Reuters on Thursday.
Biogen's Tysabri and Sanofi's Lemtrada, both injections that can have serious side effects, are currently the most powerful MS drugs, followed by pills such as Novartis' Gilenya and Biogen's Tecfidera.
Doctors often reserve more potent drugs for advanced disease but that could change because ocrelizumab has a similar safety profile to standard-of-care interferons, according to Stephen Hauser of the University of California San Francisco School of Medicine, who led two of the Roche studies.
"The findings may encourage the MS community to look more closely at earlier treatment of the disease," he said.
Drug safety is critical in MS, since the disease is caused by abnormal immune system attacks on the protective sheath surrounding nerve cells and treatments need to adjust the body's response, which can lead to problems such as infections.
Roche plans to seek regulatory approval for ocrelizumab in early 2016, implying it could reach the market around a year later.
Ocrelizumab is delivered twice-yearly via an intravenous drip. That is not a delivery system generally favoured by patients but the arrangement does mean drug administration can be worked into regular neurologist visits.
(Editing by Keith Weir)