Clinical trials on biologics in rheumatoid arthritis.

BACKGROUND

Cytokines and T cells play a major role in the pathogenesis of rheumatoid arthritis (RA). Biologic targeting is a novel therapeutic approach. Published trials in humans are discussed in this paper.

METHODS

CD4-positive T cells, proinflammatory cytokines like TNF-alpha, IL-1, IL-6 and gamma-IFN were major targets for therapy. Biologics were constructed of monoclonal human and non-human antibodies, chimerics of both, antiinflammatory regulatory proteins like IL-1 receptor antagonist, IL-10, and fusion proteins consisting of receptors and immunoglobulins.

RESULTS

More than 2000 humans with RA were exposed to biologics in the last decade. Both, toxic and safe, efficient and non-efficient drugs were tested. Phase II data could not confirm preliminary phase I data in several drugs tested. The pharmacokinetic profile of biologics is influenced by frequent induction of human anti drug antibodies.

CONCLUSION

The major role of cytokines in RA has been confirmed. Due to the limited long-term experience immunomodulation does not replace conventional pharmacotherapy.