Objective and methods: This health technology assessment (HTA) report synthesises systematically randomized controlled studies (RCT) on the therapy of moderate and severe psoriasis vulgaris which were published between 1999 and 2004; it includes some important clinical studies which have been published after 2004 and thus updates the English HTA report by Griffiths et al. [1]. The major objective is the evaluation of the medical effectiveness of different therapeutical approaches and the cost effectiveness with relevance for Germany. Results: The major conclusions from the results of medical RCT on moderate and severe psoriasis vulgaris are: Oral fumarates are effective in the treatment of moderate to severe psoriasis vulgaris. However, fumarates quiet frequently cause moderate side effects. Cyclosporine and methotrexate are both effective in the treatment of severe psoriasis vulgaris. Both substances have a different spectrum of side effects which may limit the individual applicability. Acetritin is only moderately effective in the treatment of severe psoriasis of the plaque type. Calcipotriol or UV-radiation used at the same time can increase the clinical effectiveness of acetritin. Systemic PUVA, balneo-PUVA and UVB therapy are all effective for the treatment of severe psoriasis. The combination of UV therapy with vitamin D3 analogues or with topical steroids is more effective than the treatment with UV radiation alone. Saltwater baths increase the effectiveness of UVB therapy. No RCT on the therapeutical effects of topical tar or of dithranol in combination with UV therapy have been published so far. A continuous therapy with PUVA should not be applied due to its proven photocarcinogenicity. Three substances from the group of biologicals (Efalizumab, Etanercept, and Infliximab) are now available in Europe and a further substance (Alefacept) is available in the USA for the treatment of moderate to severe psoriasis. All biologicals have been effective in placebo controlled studies. The substances differ in the times until a clinical effect is observable, in the spectrum of side effects and in their efficiency on psoriasis arthritis. From health-economic studies considering both costs and clinical efficiency oral fumarates appear to be superior to acitretin or cyclosporine (although cyclosporine appears to be more effective in severe psoriasis). From the health economic view methotrexate is equivalent with UVB or PUVA and superior to cyclosporine. The therapy options UVB, UVB plus calcipotriol and PUVA are equivalent and superior to balneo-phototherapy. Biologicals are cost intensive and should be used when other approaches are not sufficient or are not applicable due to their side effects. The HTA report summarizes some health-economic studies on dithranol, on calcipotriol and on the combination with tar and UV light. No RCT have been published for the treatment of severe psoriasis with these agents alone but it appears to be certain that these substances are effective in severe psoriasis as well.DiscussionThe spectrum of therapeutical options has fortunately increased during the last years. It must be emphasized that a number of therapeutical procedures exist which are not discussed in detail in this HTA. This is due to the search strategy of literature: Only RCT performed with patients with moderate and/or severe psoriasis vulgaris were included into this evaluation. This led to the exclusion of a number of substances which are traditionally used alone or in combination for the treatment of moderate or severe psoriasis vulgaris (e.g. dithranol, salicyc acid, tar, corticosteroids and topical retinoids). Moreover, other approaches which include neither drugs nor UV light are not discussed in this HTA although the authors believe in the importance of psychotherapeutical interventions, educational approaches and combined medical and non-medical approaches in rehabilitational medicine in the management of psoriasis vulgaris. The transferability of the health economic evaluations is strongly limited by the fact that all included health economic evaluations except one were not aligned to a German setting. A future research question will be the evaluation of the duration of remission and relapse ratios in the context of different therapy options of moderate and severe psoriasis. Moreover, the consideration of combined outcomes such as the improvement of psoriatic symptoms and the decrease of symptoms in accompanying psoriasis arthritis represents a future requirement of health assessment. Conclusions: From the clinical point of view it is positive that the spectrum of therapeutic procedures for a chronic severe skin disease has increased continuously during the last years. In cases of individual contraindications or individual inefficacies it is now possible to try alternative approaches. Moreover the risk of long-term side effects can be reduced by changing the therapeutical procedure after some time (so-called rotation therapy). The therapeutical algorithm for severe psoriasis vulgaris now includes photo(chemo-)therapy in combination with topical substances, oral fumaric acid esters, retinoids (in combination with phototherapy or topical substances), methotrexate, cylosporine and the new biologics. Future studies should address therapeutical approaches which can not easily be studied by RCT, e.g. physical, balneological, climate approaches, educational programs and complex rehabilitation therapy which all may have positive effects on individuals with severe psoriasis. As in medical therapy management of moderate and severe psoriasis the economic evaluation also points out the way of a strategic therapy concept which corresponds to a large extent to the algorithm in medical practice
