A novel gel formulation of clindamycin phosphate-tretinoin is not associated with acne flaring.

Concern exists about using topical retinoids on patients with inflammatory acne lesions, fearing that a flare in inflammation will occur. In 3 multicenter, double-blind, randomized, phase 3 trials of a clindamycin phosphate 1.2%-tretinoin 0.025% gel (CLIN/RA), clinical evaluations after 2 weeks of treatment determined if flaring occurred in participants treated with tretinoin gel 0.025% (RA) monotherapy, and the difference in inflammation when treated with the combination formulation. Flaring was assessed as an increase in inflammatory lesions of 10% or greater or 20% or greater versus baseline. Most participants experienced improvement in lesions across treatment groups. Participants with mild acne at baseline treated with RA monotherapy had significantly higher rates of flaring compared with participants treated with vehicle gel (VEH) (P < .001). Treatment with CLIN/RA or clindamycin phosphate gel 1.2% (CLIN) monotherapy resulted in significantly lower rates of flaring than RA or VEH (P < .001 for all). Participants with moderate to severe acne showed no signs of RA-induced flaring. In each comparison, the CLIN/RA combination showed the lowest percentage of increased inflammatory lesions. These results indicate that RA-induced flaring may occur with mild inflammation; combining RA with CLIN prevents this flaring. Participants with moderate to severe inflammatory acne did not show an increase in inflammatory lesions compared with participants treated with VEH. Lack of flaring may result from either the novel vehicle formulation or the antiinflammatory effects of CLIN.