Mycophenolic acid in psoriasis

Abstract

Mycophenolic acid (MPA) is a fermentation product of a penicillium mould which has shown antitumour acitivity in certain animal models. It blocks nucleic acid synthesis by interfering with the interconversions of inosine monophosphate (IMP), xanthine monophosphate (XMP) and guanine monophosphate (GMP) thereby inhibiting growth and/or replication of tumour cells. In vivo activity depends on the presence of a beta-glucuronidase which is abundant in the cell wall of epithelial tissues. Encouraged by results obtained in earlier clinical trials, we have studied 28 patients with psoriasis, 21 in double-blind fashion. A comparison of disease severity in patients before and after receiving MPA versus patients receiving placebo clearly showed the superiority of drug over placebo. The mean severity score of patients receiving MPA as an initial course of therapy improved by 56% versus 9% in patients receiving placebo. Patients receiving MPA after an initial course of placebo therapy showed improvement in their mean severity score averaging 86%. Those patients receiving placebo after an initial course of MPA showed worsening of their mean severity score averaging 70%. Overall, about 75% of MPA treated patients have shown good to excellent responses, and toxicity appears low. Evidence suggests that MPA may be very useful in treating severe psoriasis.