Arotinoid ethyl ester (Ro 13-6298): a long term pilot study in various dermatoses.

The arotinoid ethyl ester Ro 13-6298 is a third generation retinoid shown to be thousand-fold more potent than etretinate (Tigason, Tegison) in animal testing and in human therapy. In an open uncontrolled trial, we treated 57 patients suffering from psoriasis (32) and various severe skin disorders (25) with daily doses ranging from 20 to 150 micrograms, during 1 to 130 weeks (mean = 12 weeks). Four patients were treated for 1 year or more. Given in micrograms per kg range, Ro 13-6298 showed a spectrum of clinical activity and mucocutaneous side effects similar to that of etretinate given in mg per kg range. One patient developed diffuse idiopathic skeletal hyperostosis after 2 years of continuous therapy. No increase in either serum triglycerides or cholesterol levels was observed, even in patients treated for 33 to 130 weeks. This might prove to be an advantage of this new retinoid. Furthermore, this series suggests that potent mucocutaneous (therapeutical and side) effects are not necessarily linked to all other signs of retinoid toxicity.