Long-term use of a fixed-dose triple combination gel (clindamycin phosphate 1.2%/adapalene 0.15%/benzoyl peroxide 3.1% [CAB]) gel was efficacious and did not lead to the development of antibiotic resistance in patients with acne, including those with clindamycin-resistant Cutibacterium acnes (C. acnes), according to a study published in the Journal of Drugs in Dermatology and presented at the 2025 Elevate-Derm Fall Conference in Tampa, FL.
“In the context of treating patients with acne, including [benzoyl peroxide] within the same formulation as clindamycin is crucial to preventing antibiotic resistance, as fixed-dose combinations improve patient adherence to treatment compared with the use of multiple monotherapies,” study authors write.
Using pooled data from two identical, six-month, open-label studies from single centers, this analysis evaluated the effect of long-term use of CAB gel on C acnes. Patients (N=50) who were at least 12 years of age with any Fitzpatrick skin type and moderate or severe acne (Investigator’s Global Assessment [IGA] score of 3 or 4) were included in the study. Patients were instructed to apply the triple-combination gel to their faces every night for 24 weeks. No other acne products could be used during the study.
Of the 50 enrolled patients, 45 completed the study (three dropped out due to drug-related side effects and 2 due to personal reasons). Mean age of the patients was 21.8 years (range, 12-51 years), with 76% being female. All Fitzpatrick skin types were represented in the study (I-II, n=21; III-IV, n=9; V-VI, n=20).
Skin microbiome samples were collected at baseline and 24 weeks to assess cultivability and clindamycin susceptibility of C. acnes.
By week 24 (n=45), 56% of the patients showed no C. acnes growth (vs. 18% at baseline) and 33% showed clindamycin-susceptible C. acnes growth (vs. 71% at baseline). The percentage of patients who showed clindamycin-resistant C. acnes growth at baseline remained unchanged at 11% by study’s end.
“Long-term CAB treatment did not lead to the development of antibiotic resistance and was efficacious in participants with clindamycin-resistant C. acnes isolates at baseline,” the study authors wrote. Additionally, after 24 weeks of treatment, the CAB gel achieved “a nearly 50% reduction” in C. acnes growth among the patients who showed C. acnesgrowth at baseline.
“Taken together with previously published efficacy analyses, these data suggest that CAB gel is well suited to long-term acne treatment,” the authors conclude.
–Elizabeth A. Klumpp
