Additional Relevant Details The rash, also referred to as acneiform (acne-like) rash, is the most common side effect of EGFRI drugs, and can severely impact patients' physical, psychological and social well-being, often leading to treatment discontinuation or dose reduction. According to the prescription information of cetuximab and panitumumab, in the event of a severe rash, the dosing of the EGFRI drug should be withheld, reduced or discontinued.(1,2) Twenty-four patients were enrolled and received study drug in a multicenter, randomized, double-blind, placebo-controlled, Phase 2 clinical study to evaluate the safety and efficacy of FDX104. Each patient acted as his or hers own control by treating one side of the face with FDX104 and the other side with the matching foam vehicle (Placebo) in a blinded and randomized manner. Photographs of the front and each side of the face were taken at each study visit; these photographs were used for blinded grading of rash severity by an independent dermatologist at the end of the study. The ratings of rash severity were: None=0, Mild=1, Moderate=2 and Severe=3, as described by Scope et al.(3)  The key findings were:

• In the entire study population (N=24) the severity of rash on the FDX104 treatment side of the face was overall better than in the Placebo-treated side.
• The mean Maximal rash severity (N=24) was 1.33 and 1.71 in the FDX104- and placebo-treated sides respectively.
• Nine of the 24 patients in the study (37.5%) developed severe (Grade 3) rash during the study on the placebo-treated side, while only 4 of the 24 patients in the study (16.7%) developed severe rash on the FDX104-treated side.
• Comparison of the two treatments on the prevention of severe rash reached statistical significance (p<0.05, Wilcoxon Signed-Rank test). Various other exploratory analyses trended similarly.
• FDX104 appears safe and well-tolerated. No drug-related systemic adverse events were recorded. Local reactions were noted in 6 patients, all were mild and 5 were resolved before the end of the study.