How do the biologics fit into the current DMARD armamentarium?

Most disease modifying antirheumatic drugs (DMARD) are discontinued within 5 years because of loss of clinical efficacy or toxicity. As a result, there has been a concerted effort to develop new immunomodulatory agents, particularly biological agents, that block the putative proinflammatory cytokines. Among the agents developed thus far, inhibitors of tumor necrosis factor (TNF) have shown perhaps the greatest promise as therapeutic agents for rheumatoid arthritis (RA). Two TNF-blocking agents, etanercept (Enbrel) and infliximab (Remicade), have been approved in the US and more recently in Europe, for the treatment of patients with RA. The results of randomized placebo controlled trials have shown that both agents significantly decrease the intensity of synovitis and prevent or retard the progression of cartilage destruction, especially when combined with methotrexate. Their side effect profiles appear to be acceptable, although rare cases of lupus-like diseases and of severe infections have been reported. Although the early clinical experience with these agents has been encouraging, their longterm safety and continuing efficacy in the general population with RA, as well as in high risk patient subsets (i.e., patients with malignancies or chronic infections), remain to be determined. In addition, the costs of these newer agents must be justified on clinical grounds. Because of the questions still surrounding these new treatment principles, several consensus conferences have been held in Europe and the US to address the role of the new biologicals in the current RA armamentarium.