Those positive for anti-CPP or anti-RF antibodies were two to three times more likely to respond.

Rheumatoid arthritis patients who are sero-positive for either anti-CCP or rheumatoid factor (RF) antibodies are two to three times more likely to respond well to treatment with rituximab than those who don’t have the autoantibodies, according to new data presented by Roche at the EULAR annual congress.

Additional trial data from the Phase III IMAGE study showed that patients given Rituxan in addition to methotrexate therapy had three times less joint damage after a year than those given MTX therapy alone. Data from the IMAGE trial, which included 748 MTX-naïve patients, showed that adding a course of two infusions of MabThera (1,000 mg) to MTX therapy nearly doubled the percentage o f patients achieving a 70% improvement in symptoms to 47%. Eighty percent of patients given combined therapy achieved a 20% improvement in their symptoms, compared with 64% given MTX treatment only.

The autoantibody findings reported at EULAR emerged following a pooled analysis of rituximab trials and could have important implications for the 80% or so of rheumatoid arthritis patients who are sero-positive for either RF or anti-CCP, Roche suggests. The company says that the better response in sero-positive patients may be linked to one of rituximab’s modes of action, as it targets the B cells that produce the antibodies.

“Although further research is needed, these data could signal an exciting breakthrough in the future management of rheumatoid arthritis,” comments lead investigator, John Isaacs, at Newcastle University. “If we can predict which patients are likely to have the best treatment outcome with MabThera (rituximab), they can be offered this option early enough to gain maximum benefit in terms of symptom reduction and prevention of joint damage.”
Roche markets rituximab as MabThera worldwide excluding the U.S. and Japan. Genentech and Biogen Idec co-market the drug, as Rituxan, in the U.S. In Japan Chugai and Zenyaku Kogyo market the drug.

Rituximab is also approved for the treatment of relapsed or refractory, low-grade or follicular, CD20-positive, B-cell non-Hodgkin’s lymphoma (NHL), either as monotherapy or as combined therapy, dependent on lymphoma type and stage. During May 2009 Genentech and Biogen Idec submitted two sBLAs for approval of rituximab plus standard chemotherapy in the treatment of chronic lymphocytic leukemia (CLL) in previously treated or untreated patients. In January the EU’s Committee on Human Medicinal Products issued a positive recommendation for the use of rituximab with any chemotherapy combination as a first-line treatment for CLL.

Roche reported combined sales of rituximab for RA and NHL of CHF 6 billion, or about $5.59 million, in 2008. Sales were up 16% over the previous year. Genentech reported net sales of rituximab were $2.6 billion last year, up 13% over 2007.

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