New psoriasis treatments based upon a deeper understanding of the pathogenesis of psoriasis vulgaris and psoriatic arthritis: a personal appraisal of their use in practice

T he biologic age is upon us in dermatology, in parallel with most of medicine. New therapies offer great hope for people who suffer from chronic inflammatory skin diseases which have, until now, required systemic therapies that may be associated with potential end-organ damage. Psoriasis vulgaris and psoriatic arthritis are the first diseases in dermatology for which biological therapy that is targeted at various inflammatory mediators have been systematically studied, mostly in randomized, double-blind, placebo-controlled trials. Currently, these therapies target either the interaction between an antigen presenting cell and the T cell or cytokines, such as tumor necrosis factoralpha (TNF) that are presumed to be involved in the pathogenesis of psoriasis vulgaris and psoriatic arthritis. The observations that these targeted therapies are effective have led to a new understanding of these diseases, but they also give rise to a new set of questions. In the supplement that accompanies this issue, Menter and colleagues have discussed each of the major biologic therapies that are utilized to manage psoriasis vulgaris and psoriatic arthritis. In addition, they discuss therapies that are approved by the Food and Drug Administration (FDA) for other indications but which have potential to benefit patients with psoriasis (Table I). Two agents have been recently approved for the treatment of psoriasis vulgaris (alefacept: Amevive) and psoriatic arthritis (etanercept: Enbrel). Until now, a fair number of patients with psoriasis have become disaffected because of the lack of sufficiently effective and safe therapies. These emerging biologic therapies now seem to promise the potential for excellent effect without the toxicities associated with existing therapies, such as skin cancer from phototherapy, particularly psoralen plus ultraviolet A (PUVA); liver and hematologic toxicity of methotrexate (MTX); tetratogenecity of retinoids; and nephrotoxicity of cyclosporin. The papers in this month’s supplement, along with the American Academy of Dermatology–sponsored Psoriasis Therapies Educational Summit, begin to fill the need to educate dermatologists, primary care physicians, and the public about the potential for new, possibly safer therapies. What follows are my thoughts about the new therapies and the data that support their use, as well as my thoughts on how to evaluate and monitor therapy with these agents. I have elected to not reference this editorial extensively; I will highlight only those articles that I think will have a major impact on our practices. In a talk at the Plenary Session of the Annual Meeting of the American Academy of Dermatology in 1997, Richard Dobson pointed out that with each “medical advance” we seem to notice new dermatologic problems, as well as other medical issues, that our patients must face (oral communication, March 1997). Likewise, some of the new biologic agents have been associated with newly recognized, albeit rare, adverse reactions. What will these new therapies bring to dermatologists in terms of new diseases or toxicities? Should we rapidly embrace From the Division of Dermatology, University of Louisville School of Medicine. Disclosure: Dr Callen has been an investigator on a study of etanercept for psoriatic arthritis and has received honoraria either directly or indirectly from Amgen (formerly Immunex), Genentech, Biogen, Centocor, Roche, Novartis, Doak Dermatologics, 3M, and Dermik. He has also served as a consultant for Biogen, Amgen (formerly Immunex), Doak Dermatologics, ICN, 3M, and Centocor. He is the Chair of the Ad Hoc Task Force: Psoriasis Education Initiative of the American Academy of Dermatology and was the Chair of the Psoriasis Therapies Educational Summit that was held in Louisville, Ky on November 2-3, 2002. Reprint requests: Jeffrey P. Callen, MD, Chief, Division of Dermatology, University of Louisville School of Medicine, 310 East Broadway, Louisville, KY 40202. J Am Acad Dermatol 2003;49:351-6. Copyright © 2003 by the American Academy of Dermatology, Inc. 0190-9622/2003/$30.00 0 doi:10.1067/S0190-9622(03)01149-6