A rheumatoid arthritis drug developed by Roche’s majority-owned Japanese partner Chugai has achieved clinical results in a Phase III study that, at first glimpse, seem to be way ahead of its rivals, according to analysts.

Data on tocilizumab, formerly known as MRA, indicate that the drug was significantly more effective than standard treatment in alleviating symptoms in RA patients, with 47% of those treated with the antibody achieving a 70% improvement in symptoms (ACR 70 response), compared to just 6% of patients receiving conventional treatment with disease-modifying antirheumatic drugs (DMARDs).

The data is available in abstract form in advance of its formal presentation at the American College of Rheumatology annual meeting next month.

Analysts at Deutsche Bank and Morgan Stanley said the abstract data indicate that tocilizumab, which blocks the activity of interleukin-6, could be major new treatment option in RA. The drug is already marketed in Japan under the trade name Actemra after approval as a therapy for Castleman's disease in April this year.

Meanwhile, Roche is also due to present Phase III data on its lymphoma drug MabThera/Rituxan (rituximab) in RA patients who have failed other therapies at the ACR meeting. Roche filed for approval of this indication earlier this year [[06/09/05g]].

If tocilizumab and Rituxan make it to market for RA, Roche could have two products with the potential to achieve sales of more than $1 billion in RA, according to Denise Anderson of Kepler Equities.

The overall market for RA treatments is tipped to double in size from $5.5 billion at present to $10.5 billion in 2008.