Systemic therapy with fumaric acid derivates: new possibilities in the treatment of psoriasis.

For the past two decades fumaric acid (FA) therapy has become an increasingly popular treatment in Western Europe for psoriasis. FA therapy originally was developed by Schweckendiek and subsequently standardized by Schäfer. Schäfer's fumaric acid compound therapy (FACT) consists of the oral intake of dimethylfumaric acid ester (DMFAE) and several salts of monoethylfumaric acid ester (MEFAE) in combination with topical fumaric acid therapy (1% to 3% MEFAE in an ointment or FA in bathing oils) and a diet. Schäfer claimed excellent results in a large number of patients. Preliminary studies by German dermatologists, however, revealed contradictory therapeutic results and serious side effects, and FA treatment was soon abandoned by dermatologists. To assess the value of FA therapy we conducted an open pilot study of 36 patients in which FACT therapy appeared to be rather effective. Thereafter, several controlled studies with MEFAE sodium in two different dosages versus placebo, and DMFAE versus placebo, were done. The results indicated that MEFAE sodium in dosages up to 240 mg daily was ineffective, whereas daily dosages of 720 mg resulted in a significant decrease in scaling and itching but did not affect extension of the eruption. DMFAE, 240 mg daily, produced a significant amelioration and prevented extension. Side effects of FA treatment were nausea, diarrhea, general malaise, and severe stomachache. Mild disturbances of liver and kidney function during treatment were observed with the 720 mg dosage of MEFAE and with the 240 mg dosage of DMFAE. Moreover, a relative lymphopenia with a selective decrease of suppressor T lymphocytes occurred in about 50% of the patients treated with DMFAE.(ABSTRACT TRUNCATED AT 250 WORDS)