FOCUS ON: Biologics that Affect Therapeutic Agents in Dermatology

Tumor necrosis factor (TNF)-α is one of the oldest known cytokines in human physiology. It is involved in both normal and pathologic states. Virtually every cell and organ in the body are affected by TNF-α.¹ Though TNF-α is usually involved in inflammation as a normal host defense response, when overproduced, it can become pathologic and affect almost every organ system. In this article, we address the role of TNF-α in diseases such as rheumatoid arthritis, Crohn's disease, psoriasis, and ankylosing spondylitis as well as the drugs used to modulate TNF-α. Specifically, we look at the structure, mechanism of action, and clinical use for etanercept, infliximab, and adalimumab. Historically, we also review the drug lenercept, another TNF-α modulator. These drugs offer alternative effective treatments to rheumatologic and dermatologic diseases without as many of the toxic side effects of some of the traditional therapies. The traditional agents target TNF-α in addition to several other modes of action (disease modifying anti-rheumatic drugs [DMARDS] such as cyclosporine and methotrexate) (Table 1).

Though TNF-α immunomodulation seems to be a very effective, promising treatment in several TNF-α mediated disease processes, long-term studies need to be performed to assess the risk-benefit ratio of using these drugs over an extended period of time.