Cutis. 2009 May; 83(5): 265-72Dhawan SSCombination therapy for the topical treatment of acne vulgaris using benzoyl peroxide (BPO) and an antibiotic is more efficacious and better tolerated than treatment with either component alone. Moreover, the addition of BPO to antibiotic therapy is recommended as a means of preventing the development of Propionibacterium acnes antibiotic resistance. However, BPO is an irritant, and the dryness and irritation experienced by some patients using topical therapy containing BPO can negatively impact compliance. Historically, once-daily treatment application has enhanced compliance versus twice daily. The current 12-week study aimed to compare the efficacy of a clindamycin 1%-BPO 5% topical gel with the hydrating excipients dimethicone and glycerin (C/BPO HE) and a clindamycin 1%-BPO 5% topical gel that does not contain hydrating excipients (C/BPO) applied once daily for the treatment of 20 participants with facial acne vulgaris and to determine if there were differences in product preference and participant acceptability between the treatments. Both C/BPO HE and C/BPO were effective in the treatment of acne, with substantive reductions (-60.8% and -61.3%, respectively) in total inflammatory lesions at week 4 in both treatment groups. Participants receiving C/BPO HE demonstrated a more consistent treatment response than with C/BPO, with incremental reductions in total inflammatory lesions at each time point, whereas the response to C/BPO waned at week 8. As a result, greater percentage reductions in inflammatory and noninflammatory lesions were observed with C/BPO HE treatment than C/BPO treatment at week 8 (papules: -71.9% vs -49.4%, P=.053; pustules: -64.8% vs -28.0%, P=.134; open comedones: -44.5% vs 2.6%, P=.480; closed comedones: -35.5% vs -26.3%, P=.501). With the exception of papules, greater reductions in all lesion subtypes also were observed at week 12. None of the between-group differences reached statistical significance. Both treatment groups displayed similar disease signs and symptoms throughout the study period. However, scaling, erythema, dryness, and pruritus occurred more frequently in participants using C/BPO. Treatment satisfaction was greatest with C/BPO HE; participants reported that this formulation was easy to apply and 100% (9/9) of participants reported that they would continue using C/BPO HE compared with 80% (8/10) of participants using C/BPO. Both treatments were well-tolerated. In this pilot study, both formulations were effective in the treatment of inflammatory and noninflammatory acne lesions, but C/BPO HE produced a more consistent reduction in total inflammatory lesions over 12 weeks. The addition of hydrating excipients in the C/BPO HE formulation appears to improve patient tolerance and acceptance, which will likely help patients to comply with therapy.