Efficacy and Safety of Topical Adapalene (0.1% w/w) and Clindamycin (1% w/w) versus Topical Adapalene (0.1% w/w) and Benzoyl Peroxide (2.5% w/w) in Inflammatory Acne Vulgaris: A Phase-IV Open-label Comparative Study

Introduction: Acne vulgaris, a chronic inflammatory condition, is characterised by open and closed comedones, erythematous papules and pustules. In current treatment guidelines, topical retinoids, such as adapalene, are commonly prescribed in combination with antimicrobials, including clindamycin. This combination has been proven to reduce acne lesions more quickly and prevent antimicrobial resistance. Benzoyl Peroxide (BPO) has a synergistic effect that enhances the penetration of adapalene in the skin and prevents the growth of Propionibacterium acnes. No published studies have compared topical adapalene and clindamycin versus topical adapalene and BPO.

Aim: To compare the efficacy and safety of a combination of topical adapalene (0.1% w/w) and clindamycin gel (1% w/w) with a combination of topical adapalene (0.1% w/w) and BPO (2.5%w/w) gel for the treatment of inflammatory acne vulgaris .

Materials and Methods: This study was a prospective randomised, open-label, parallel group interventional trial, which was conducted in the Departments of Pharmacology and Dermatology at NRS Medical College and Hospital, Kolkata, West Bengal, India, from January 2023 to August 2023. The total sample size was 34, with 17 in each group. Patients fulfilling the inclusion criteria were assigned to one of the two study groups in a parallel-arm design. Patients in Group A had received topical adapalene (0.1% w/w) and clindamycin (1%w/w) and patients in Group B had received topical adapalene (0.1% w/w) and BPO (2.5%w/w). Randomisation was done by the coin-toss method. Changes in Total Lesion Count (TLC), Investigator Global Assessment (IGA) score and Cardiff Acne Disability Index (CADI) score were recorded at weeks 0, 4, 8, and 12. Friedman’s test and repeated measure Analysis of Variance (ANOVA) test were used for intragroup comparison and Mann-Whitney U test and Unpaired t-test were applied for intergroup comparison. Chi-square test was used for categorical data. A p-value<0.05 was considered statistically significant.

Results: No statistically significant intergroup differences existed at baseline in TLC, IGA score and CADI score. Intragroup comparisons in both groups showed a significant decrease in TLC, IGA and CADI scores at week 12 from their respective baseline values (p-value<0.05), but intergroup comparison showed no statistically significant difference at week 12.

Conclusion: It was observed that consecutive topical treatment with clindamycin and adapalene appears to possess additive effects that can be of valuable therapeutic benefit for acne patients. It has been observed that topical treatment with adapalene and BPO has good efficacy and tolerability. It has been found that both treatment therapy is beneficial and safe for mild to moderate acne vulgaris patients.