A top-selling cancer drug co-developed by Switzerland’s Roche also helps patients with a hard-to-treat form of Rheumatoid Arthritis, data showed on Wednesday, opening the door to a potential major new market.

The treatment, known as MabThera/Rituxan, significantly improved symptoms in Rheumatoid Arthritis patients with the most difficult to treat form of the disease in late-stage clinical trials, the data showed. The drug, already sold as a treatment for lymph cancer and tested as a treatment for arthritis, is co-developed and marketed by Roche, its U.S. biotech arm Genentech, and Biogen Idec Inc.

Analysts said the results would form the basis of the drug’s launch as a treatment for rheumatoid arthritis in patients for whom current medicines do not work.

They noted it could be another significant market for the drug, which already generated sales for Roche of over 3 billion Swiss francs ($2.48 billion) in 2004.

“The important thing is this could be a second blockbuster indication for the product,” analyst Denise Anderson at Kepler Equities said.

Roche certificates, its most widely traded form of equity, were 1.2 percent higher at 131.60 Swiss francs on the news.

“This initial indication should be supplemented with approval to treat RA (rheumatoid arthritis) patients earlier in their disease,” analysts at Nomura said in a note.

Analysts said uptake for the drug in the difficult-to-treat form of the disease would be relatively modest due to recently launched competitors, but that sales to RA patients could reach over 1 billion francs by 2010 if wider approval is granted.

NEW HOPE

The phase III study involved patients who had tried existing treatments and had seen no benefits or had been unable to tolerate them.

A greater number of those patients saw their symptoms improve with the drug after 24 weeks compared with those taking a placebo.

“These data suggest that MabThera may offer new hope to patients who have explored all existing therapies,” William Burns, chief executive of Roche’s pharmaceutical division, said in a statement.

“We are pleased that MabThera’s value has now been demonstrated in this group of patients with the most difficult-to-treat rheumatoid arthritis and for whom there are currently no adequate treatment alternatives,” he said.

Roche said the data from the latest phase III trial complemented the results from earlier phase II studies for patients with moderate-to-severe arthritis and supported the idea that the drug could be an important treatment for rheumatoid arthritis.

The companies plan to file for regulatory approval of the treatment for patients with difficult-to-treat rheumatoid arthritis in the second half of this year. The drug is already on the market as a treatment for non-Hodgkin’s lymphoma.

MabThera - an antibody targeting B cells which play an important role in the inflammatory cascade behind rheumatoid arthritis - generated sales of 3.38 billion francs in 2004 from its current indication.

Rheumatoid arthritis is one of the most common forms of autoimmune disease and affects more than 6 million people worldwide, including up to 2 million in Europe, Roche said.