Introduction

The introduction of biologic agents for the treatment of moderate-to-severe psoriasis has the potential to transform our approach to psoriasis treatment. In the past, greater treatment efficacy was also associated with greater, often unacceptable, safety concerns. This constrained our use of the most effective psoriasis treatments (phototherapy, cyclosporine, methotrexate, and oral retinoids) and would often leave patients who had more severe disease greatly underserved.¹ The biologic agents, in contrast, offer a range of effective treatment options free of many of the safety concerns commonly associated with nonbiologic systemic treatments for moderate-to-severe psoriasis. This enables us to move away from the stepwise approach to therapy (which required patients to fail on less effective therapies before systemic or phototherapy could be considered) and move toward a more balanced approach that allows all therapies to be considered equally from the beginning.²

At dermatology meetings throughout 2004, physicians described how the availability of biologic therapies had changed the way they treat moderate-to-severe psoriasis. Some physicians reported significant reductions in their use of methotrexate, acitretin, and cyclosporine, as well as a decreased use of combination therapy. Others reported that biologic agents had become their first-line therapies of choice for all patients with moderate-to-severe psoriasis (when insurance coverage is available). Moreover, all physicians who have incorporated these biologic agents into their practice described numerous examples of patients who have been able to get their disease under long-term control for the first time in their lives.

The ability to determine the most appropriate approach to biologic therapy for a given patient has been greatly enhanced by the volume of important research that has been conducted on these agents in the past year. While much has been learned about how to transition patients to biologic therapy, what to expect during therapy, how to improve the chances of treatment success, and how to manage some of the problems that may arise during or after discontinuation of therapy, much research still needs to be done. To date, all of the biologic agents seem to have good safety profiles in the treatment of psoriasis, but often an association between a drug and a rare but potentially serious adverse effect is not discovered until after a drug is in widespread clinical use. Consequently, it is important to document and report all serious adverse events occurring during biologic therapy and to analyze the cumulative results appropriately.

There is a tendency to discuss the biologic agents as a class, but this review will make it clear that all of the biologic agents are different. Each biologic agent has its own unique mechanism of action and offers a unique set of advantages and disadvantages. Figure 1 illustrates some of the fundamental differences between the T-cell agents efalizumab and alefacept and the tumor necrosis factor (TNF) blockers etanercept, infliximab, and adalimumab. As this figure shows, the TNF-blocking agents affect more body systems than do the T-cell agents. Because each psoriasis patient is unique and no single therapy is effective in all patients, the diversity of biologic agents, in itself, has great advantages. The availability of a wide range of biologic agents increases the chances that an effective, safe, and convenient treatment option will be found for any given psoriasis patient. This review provides a guide to our current collective understanding of the different biologic agents for the treatment of moderate-to-severe psoriasis.

Figure 1 Click to view larger image