Biomarkers predict rheumatoid drug success

Rheumatoid arthritis (RA) patients who test positive for the auto-antibodies rheumatoid factor (RF) or anti-cyclic citrullinated peptide (aCCP) are more than twice as likely to achieve remission and are three times more likely to get a significant improvement in symptoms when taking MabThera (rituximab) plus methotrexate (MTX) than those who test negative, according to new research presented at the British Society of Rheumatology (BSR) annual conference.

The research consisted of two phase III studies led by Professor John Isaacs, professor of clinical rheumatology at Newcastle University, and involved eight centres in which patients with active RA who had previously experienced an inadequate response to other disease-modifying anti-rheumatic drugs (DMARDs) were treated with the monoclonal antibody rituximab plus MTX. A total of 670 patients (554 seropositive and 116 seronegative) were pooled and analysed.

At week 48, 44.9 per cent of seropositive patients achieved a 50 per cent reduction in the signs and symptoms of RA, compared with the 22.8 per cent of seronegative patients who achieved the same degree of improvement.

Professor John Isaacs commented: "By identifying in advance which groups are most likely to respond to, or to have an enhanced response to, drugs like rituximab, we can ensure they are treated early enough to prevent irreversible joint damage and disability. Additionally this will reduce treatment costs by avoiding the use of ineffective drugs."

This constitutes the first time research into the treatment of RA has been able to identify biomarkers to pinpoint which patients would respond better to any specific treatment. Approximately 80 per cent of patients with RA are seropositive for one of these auto-antibodies. The economic burden of RA is currently estimated at almost £8bn annually.