Poor prognostic factors and unmet needs in rheumatoid arthritis.

Prognostic factors in rheumatoid arthritis relate to several aspects, such as prediction of joint damage and loss of function or prediction of response to a particular therapy. For many decades it has been well established that high disease activity, especially exemplified by swollen joint counts and acute phase reactants, is associated with progression of joint damage. In addition, rheumatoid factor (RF) positive patients, but not patients with anti-citrullinated peptide antibodies (ACPA) are particularly prone to high disease activity and joint destruction. Newer studies have looked at molecular markers, but they have either not shown better results than those seen with the long-established ones or have not been sufficiently validated. Most recent insights suggest that high C-reactive protein levels may predict a particularly good response to IL-6 blockade, but not to other therapies, and that high RF-levels may be associated with better responses to Fc-free monoclonal antibodies than molecules containing an Fc-region. It is hoped, however, that with newer techniques and better insight into RA pathogenesis research may come up with even better molecular markers than currently available to predict responses to specific drugs in the not-too-distant future.