York Pharma plc, of Hitchin, UK, announced that its lead vitamin A pathway inhibitor, carbenoxolone, demonstrated clinical activity in 12 patients with mild to moderate psoriasis who were enrolled in a randomized, double-blind, phase II study comparing carbenoxolone to calcipotriol (a vitamin D analog) or placebo. Two percent carbenoxolone gel (unoptimized for formulation or concentration), applied daily for 4 weeks, resulted in a reduction in the redness, scaling, and thickness of plaques, and demonstrated clinical activity according to the guidelines established by the European Medicines Agency (EMEA). No adverse reactions were reported. York plans to undertake additional phase II studies with an optimized formulation, including dose-ranging studies.   

According to York, carbenoxolone, an existing medicinal product, inhibits a specific enzyme upregulated in psoriasis that is responsible for the cellular production of retinoic acid. Both in vivo and in vitro data generated from studies in models of psoriasis with carbenoxolone have confirmed that the product compares favorably with vitamin D analogs (such as calcipotriol), the current standard therapies for mild to moderate psoriasis. Carbenoxolone may be differentiated from the vitamin D analogs by  its lower risk of skin irritation, improved safety profile, and lack of evidence of tolerance to ongoing treatment.

—A. Techman