Impact of Microencapsulated Benzoyl Peroxide on the Skin Microbiome and Clinical Outcomes in Rosacea: An Update on a Randomized, Double-blind, Crossover, Vehicle-controlled Clinical Trial.

Objective: We sought to evaluate changes in skin microbiome biodiversity and correlation with rosacea improvement of microencapsulated benzoyl peroxide (E-BPO) versus vehicle cream in rosacea patients in a 12-week crossover study with a no-treatment period of four weeks (Week 16).

Methods: This was a randomized, double-blind, single-center, crossover, vehicle-controlled evaluation of E-BPO on the skin microbiome in rosacea. Thirty-one participants had facial rosacea with global severity of 3 or 4 on the Investigator's Global Assessment (IGA) scale. Participants were randomly assigned to two groups. The E-BPO/vehicle group applied E-BPO for eight weeks, then vehicle for four weeks. The vehicle/E-BPO group applied vehicle for eight weeks, then E-BPO for four weeks. Clinical assessments were performed using IGA, inflammatory rosacea scale, and erythema scale. Determination of change in skin microbiome was based on facial swab sampling.

Results: Shifts in the microbiome correlated with improvements in IGA, inflammatory rosacea, and erythema. At Week 8, similar bacterial species diversity profiles were observed among all participants. After crossover of the vehicle/E-BPO group at eight weeks to E-BPO, the relative abundance of was markedly lowered, and the relative abundance of was slightly increased. In the E-BPO/vehicle group, the relative abundance of and at Weeks 12 and 16 remained at the level observed at Week 8.

Limitations: The study had a short duration, which may not fully capture the long-term effects and durability of E-BPO in real-world clinical practice.

Conclusion: Even after withdrawal at 16 weeks, efficacy and shifts in the skin microbiome were maintained over the duration of the study period with demonstrated clinical improvement and a well-tolerated safety profile.