During the winter of 1971/72, eleven dermatologists in private practice and the dermatological departments of the Finsen Institute and Marselisborg Hospital conducted a controlled clinical trial to investigate the effect of topically applied tretinoin in patients with acne vulgaris using a 0.02-percent cream, a 0.05-percent cream, and the cream base alone. The effect of the treatment was evaluated by counting the acne lesions, the number being arranged according to a score system. As regards the effect on comedones and papules, the tretinoin cream was significantly better than the cream base alone. A concentration of 0.05% showed a quicker onset of action and a more pronounced effect than a concentration of 0.02%. The effect of the treatment was less pronounced and not statistically significant as far as pustules and cysts were concerned. The investigation confirmed previous good experience with this form of treatment. The effect upon the placebo group was considerable. This calls for caution when the effect of new acne agents is to be evaluated. Attention is drawn to the special form of cooperation used in the investigation; in this way, it was possible to include a great number of out-patients.

The effect of a new non-steroid anti-inflammatory substance (bufexamac) in a special constituent was compared with that of 0.1% triamcinolone acetonide, 1% hydrocortisone cream, and placebo during a double-blind multicentre trial. The clinical effect of these four creams was studied in 193 patients receiving treatment for the following skin disorders: atopic dermatitis, allergic contact dermatitis, and non-allergic contact dermatitis, as well as dermatitis seborrheica. After 2 and 4 weeks’ treatment, when 193 and 157 patients, respectively, were re-examined, the effect of triamcinolone acetonide and hydrocortisone cream was significantly better, than that obtained with bufexamac in the cream basis employed. On the other hand, no statistically significant difference in effect between bufexamac and placebo cream was observed.

A double-blind, controlled multi-centre trial with 238 patients was employed to study the relative merits of three treatment schedules in acne vulgaris. Schedule A consisted of oral oxytetracycline and topical vitamin A acid cream (0.05%), schedule B of oral oxytetracycline alone, and schedule C of vitamin A acid alone. Large and statistically significant reductions occurred in the number of come dones, papules and pustules during 8 weeks of therapy, which could be attributed neitherto placebo effects nor to natural history of the disease.

In a double-blind randomized comparative multicenter trial, consisting of 29 patients with acne vulgaris who were unable to tolerate daily applications of retinoic acid, the retinoic acid derivative Ro 11–1430 (0.1% vanishing cream) was compared in a 6–8 weeks topical treatment with vanishing cream alone (placebo). Regarding efficacy, for most criteria measured the response was always better with Ro 11–1430 than with placebo, although the differences were not always statistically significant for several reasons, one probably being the small number of patients in the trial. Regarding tolerance, both treatments were satisfactory. Ro 11–1430 and placebo did not differ significantly regarding frequency and severity of erythema, desquamation and burning. These results suggest that treatment with Ro 11–1430 should be considered in acne patients who are unable to use retinoic acid due to severe local reactions.