A once-daily, fixed-dose, triple-combination gel comprising clindamycin phosphate 1.2%, adapalene 0.15%, and benzoyl peroxide 3.1% (Cabtreo, Ortho Dermatologics) significantly reduces biofilm formation and porphyrin production in clinical isolates of Cutibacterium acnes, a new study shows.
The in vitro findings, presented at the 2026 American Academy of Dermatology Annual Meeting in Denver, CO, suggest that Cabtreo’s effects may extend beyond direct antibacterial activity
C. acnes is a common commensal bacterium found within pilosebaceous units, but it can become pathogenic in acne vulgaris through the production of biofilms and other virulence factors. These mechanisms may contribute to inflammation, bacterial adaptation, and reduced responsiveness to treatment.
For the study, investigators explored whether Cabtreo could interfere with several of these pathways, including biofilm formation, porphyrin production, and lipase activity.
They evaluated 18 clinical C. acnes isolates obtained from patients with acne. Isolates were cultured anaerobically and exposed either to no treatment or to Cabtreo at concentrations equal to five times or 10 times the minimum inhibitory concentration (MIC) required to inhibit 80% of bacterial growth. Researchers then assessed virulence factor expression using commercially validated assays.
Cabtreo significantly reduced biofilm formation across all 18 C. acnes isolates tested. Confocal imaging demonstrated visibly reduced biofilm structure following Cabtreo exposure, including weaker fluorescence signals and reduced biofilm thickness compared with untreated controls.
Cabtreo also significantly reduced porphyrin production, another virulence factor linked to acne inflammation. In the study, Cabtreo reduced porphyrin levels by 64% at five times the MIC and by 80% at 10 times MIC compared with untreated controls, the study showed.
In contrast, Cabtreo did not affect lipase activity or lipase gene expression in any of the isolates tested.
The study was limited to laboratory analyses, and additional research will be needed to determine whether the findings translate into improved clinical outcomes in patients with acne.
