Use of an alternative method to evaluate erythema severity in a clinical trial: difference in vehicle response with evaluation of baseline and postdose photographs for effect of oxymetazoline cream 1·0% for persistent erythema of rosacea in a phase IV study

The phase IV study assessed the effectiveness of oxymetazoline cream 1.0% in reducing persistent facial erythema of rosacea by comparing baseline and post-treatment photographs in 835 patients. Results showed that significantly more patients treated with oxymetazoline achieved at least a 1-grade improvement in Clinician Erythema Assessment (CEA) compared to those receiving a vehicle, with up to 80.2% of oxymetazoline-treated patients showing moderate improvement versus 22.9% of vehicle-treated patients. The study concluded that referencing baseline photographs improved the accuracy of erythema severity assessments and mitigated the vehicle effect seen in phase III trials. This method could enhance clinical trial accuracy for erythema evaluation, with consistent results across different skin types and a correlation between patient satisfaction and erythema improvement.