Appropriate Use of Alefacept Therapy for Psoriasis—Reply

In the study titled "An International Randomized, Double-blind, Placebo-Controlled Phase 3 Trial of Intramuscular Alefacept in Patients With Chronic Plaque Psoriasis," by Lebwohl et al,¹ and the corresponding editorial comments by Dr Gottlieb,² much is made of the "durability" of the response to alefacept (Amevive; Biogen Inc, Cambridge, Mass), while the durability of the response to placebo is ignored. Extrapolating the numbers from Figure 3 in the article shows that 42% of patients who received 15 mg of alefacept for 12 weeks achieved a reduction of at least 50% in the Psoriasis Area Severity Index (PASI) score. The improvement was maintained for 12 weeks after therapy in 71% of the patients. Although this "durable," or long-lasting, response of 71% may appear impressive, the corresponding number for the placebo group was 90% (17% showed 50% reduction in the PASI score, and 90% maintained this improvement 12 weeks later).

Also, if we determine the "number needed to treat" in this population using alefacept weekly for 12 weeks to achieve at least 50% reduction in the PASI score at 24 weeks, we might have trouble rationalizing the tremendous expenditure. If the numbers from Figure 3 were extrapolated, the number needed to treat would be 8. In that the drug expense alone is $10 000 per patient, the cost to achieve this result (ie, 50% reduction in PASI, maintained for 12 weeks after treatment) in 1 patient would be $80 000 plus physician charges for 8 patients. When used as an alternative therapy in the exceptional patient with severe psoriasis who is unable to tolerate any other therapies, this response rate and expense may be acceptable. However, if we begin using this therapy for the Food and Drug Administration–approved indication of "adult patients with moderate to severe chronic plaque psoriasis who are candidates for systemic therapy or phototherapy," I believe that we will be doing a disservice to our patients. Ultimately, patients will be paying for this through more expensive or possibly unaffordable health insurance premiums. Patients with psoriasis who are seeking to obtain health insurance may even be excluded because of concern about the potential recommendation by physicians of such costly treatments.

The author has no relevant financial interest in this letter.