[Oral treatment of acne conglobata using 13-cis-retinoic acid. Results of the German multicentric study following 24 weeks of treatment].

Results of the isotretinoin (13-cis-retinoic acid, Ro 4-3780) German Cooperative Study Group, with 198 acne conglobata patients being treated in 19 departments are reported. For the first 12 weeks (phase I) there was an open assignment to 0.2, 0.5 or 1.0 mg/kilogram bodyweight (kg bw). This was followed by further 12 weeks (phase II). If there was at least a two-third improvement of lesions, the 0.2 mg/kg bw was continued, and the 0.5 mg/kg bw dose lowered to 0.2 mg/kg bw. If there was no such improvement, the dose was elevated to 0.5 and 1.0 mg/kg bw respectively. The initial high dose group of 1.0 mg/kg bw was divided after twelve weeks into 0.2 mg/kg bw maintenance therapy, or no therapy at all. Non-inflammatory and inflammatory acne lesions from the entire body were counted. Seborrhea was graded on a four scale (0 to 3+). Subjective side effects were registered. Laboratory data included hematological profile with differential counts, creatinin, SGOT, SGPT, alkaline phosphatase, total bilirubin, serum cholesterol and serum triglycerides, and urine analysis. For statistical analysis 171 patients were available, 27 dropped out of the study, mostly for reasons unrelated to the drug. At least 75 per cent improvement was seen, in the 0.2 mg/kg bw group in 73.7 and 59.5 per cent respectively; in the 0.5 mg/kg bw group in 72.5 and 61.2 per cent respectively; and in the 1.0 mg/kg bw group in 85.4 and 92 per cent respectively (phase I t12 and phase II t24 values, respectively). Sebum suppression was dose-related. Subjective side effects were fairly well dose-related, particularly those of skin and mucous membranes. Myalgia was rare. There was a dose-related elevation of triglycerides and cholesterol, but not significant for the means of each group. Single patients did show significant elevation of blood lipids. All other laboratory parameters did not change significantly. Isotretinoin is presently the most effective drug to control severe forms of acne, leading to long lasting remissions.