Supplementary Material for: Reduction of Inflammatory and Noninflammatory Lesions with Topical Tyrothricin 0.1% in the Treatment of Mild to Severe Acne Papulopustulosa: A Randomized Controlled Clinical Trial

<b><i>Background/Aims:</i></b> Antibiotic-induced drug resistance requires new approaches in topical acne treatment. Tyrothricin is known to produce no resistance. In this study, it was tested for the first time in topical acne treatment. The efficacy and tolerability of topical tyrothricin 0.1% was evaluated. <b><i>Methods:</i></b> A<b> </b>randomized, active comparator-controlled, exploratory, observer-blind clinical study was conducted in 24 patients with acne papulopustulosa. Randomization on a split-face was either tyrothricin versus clindamycin + benzoyl peroxide (BPO) (n = 12) or tyrothricin versus BPO 5% (n = 12). The main outcome was change in inflammatory and noninflammatory lesion counts. <b><i>Results:</i></b> The mean differences in inflammatory lesion counts from baseline were -12.3 (95% CI: -20.5 to -4.1) in clindamycin + BPO, -10.2 (95% CI: -15.3 to -5.0) in BPO 5%, and -7.7 (95% CI: -11.7 to -3.7) in tyrothricin. Tyrothricin reduced noninflammatory lesions (mean difference: -6.5 (95% CI: -11.6 to -1.4) and caused less product-related adverse events (n = 31) compared to BPO (n = 37) and clindamycin + BPO (n = 20). <b><i>Conclusion:</i></b> The results indicate that tyrothricin might be a candidate for treating acne and it seems to be more tolerable than both comparator treatments.