Isotretinoin 5 mg daily for low- grade adult acne vulgaris - a placebo- controlled, randomized double- blind study

BackgroundDespite acne persisting into adulthood in up to 50% of the population, very few therapeutic studies have been performed in this age group. ObjectivesTo assess the efficacy of 5mg/day isotretinoin in adult acne. MethodsAn investigator initiated, industry-sponsored, randomized, double-blind, placebo-controlled, parallel-group clinical study of isotretinoin 5mg/day in the treatment of low-grade adult acne for 16weeks followed by an open-label phase of 16weeks. Group 1 received 32weeks of 5mg isotretinoin/day; Group 2 first received 16weeks of placebo, followed by 16 weeks open-label 5mg isotretinoin/day. Patients were followed for a further 10 weeks off treatment. The primary end-point was the difference in acne lesion count and disability score after 16 weeks isotretinoin compared to placebo. Secondary end-points included differences in these counts/scores after 32weeks of isotretinoin compared to baseline, and after 10 weeks off treatment, compared to end of treatment (week 32). ResultsThere were highly significant differences (P<0.0001) in acne lesion count, Dermatology Life Quality Index and self-assessment after 16weeks of isotretinoin, compared to placebo (both per protocol and intention to treat). Acne lesions fell significantly, within 4weeks of 5mg isotretinoin/day (Group 1) and continued to fall during 32weeks of treatment [acne lesion count (meanSD): 11.3 +/- 8.1 (baseline), 3.6 +/- 5.5 (week 16), 1.3 +/- 3.1 (week 32), P<0.0001)]. There was a similar significant reduction in acne lesion count in Group 2, but only from week 20, 4weeks after starting open-label 5mg isotretinoin. Adverse effects were minimal. ConclusionsIsotretinoin 5mg/day is effective in reducing the number of acne lesions, and improving patients dermatologic quality of life, with minimal adverse effects.