While they act in the best interest of the patient to limit disease morbidity, physicians must consider costs associated with treatment to ensure efficient health resource allocation.39 Factors such as efficacy and tolerability must also be considered. Cost-effectiveness analyses of systemic treatments for psoriasis, such as the biologic drugs, have recently been published.9,16,22,23 A study by Feldman and coworkers,23 which used a 75% improvement in Psoriasis Area and Severity Index (PASI-75) scores as a measure of treatment success, found that methotrexate is the most cost-effective treatment ($5400 per treatment success annually), whereas alefacept has the highest cost ($40 600) per treatment success. When they factored in considerations of safety, the authors suggested UV-B phototherapy as the first-line agent of choice for severe psoriasis because of the higher risk profile of methotrexate. Regarding the cost-effectiveness of biologic therapies, studies16,23 suggest that adalimumab and infliximab are the most cost-effective biologic therapies, whereas efalizumab and alefacept are the least cost-effective on the basis of the PASI-75 analyses. Similar results were obtained by Sizto and coworkers,40 who demonstrated that infliximab provided the greatest increase in quality-adjusted life-years (QALYs) relative to supportive care (0.18 QALY), followed by adalimumab (0.16 QALY). Although methotrexate (0.13 QALY) and cyclosporine (0.08 QALY) were less beneficial, they were found to be the most cost-effective treatments for moderate to severe psoriasis. Several studies of efficacy and tolerability of psoriasis therapies do not factor cost into their analyses. A study41 of 12 trials that compares PASI-75 reduction rates at 12 weeks of treatment revealed the following rates: infliximab, 80%; adalimumab (40 mg/wk), 80%; cyclosporine, 78.2% to 80.3%; PUVA, 63%; methotrexate, 60%; UV-B, 55%; acitretin, 52%; etanercept (50 mg/wk), 34%; efalizumab, 31.4%; and alefacept, 21%. Similarly, an analysis42 of 24 randomized controlled trials of systemic psoriasis treatments, including cyclosporine, methotrexate, fumaric acid esters, and biologic treatments, suggested that infliximab is the most efficacious agent (75.5%-87.9% of patients met the PASI-75 criterion after 10 weeks), followed by adalimumab (an average of 64% met the criteria after 16 weeks). The study indicated that these agents are superior in efficacy to cyclosporine, methotrexate (although long-term studies are lacking), etanercept, efalizumab, and fumaric acid esters. Analysis of short-term tolerability demonstrated that methotrexate had the highest rate of withdrawal (7.3% average monthly incidence rate) secondary to adverse effects, with gastrointestinal upset the most frequent symptom. Biologic treatments demonstrated similar overall adverse events and withdrawal rates (16.6%-28.3% and 0.3%-1.3%, respectively); however, the type of adverse event differed. Infusion reactions were seen more frequently with infliximab, whereas injection site reactions were more frequently associated with etanercept, and upper respiratory tract infections with adalimumab.42 Long-term studies and head to head comparisons of tolerability for the various systemic treatments available for psoriasis are lacking and remain an area for future study.