Prophylactic tetracycline does not diminish the severity of epidermal growth factor receptor (EGFR) inhibitor-induced rash: Results from the North Central Cancer Treatment Group (SUPPL.ementary N03CB)

Purpose: Previous studies suggest tetracycline and other antibiotics lessen the severity of epidermal growth factor receptor (EGFR) inhibitor-induced rash. This study sought to confirm such findings. Methods: Patients starting an EGFR inhibitor were eligible for this randomized, double-blinded, placebo-controlled study and had to be rash-free. They were then randomly assigned to tetracycline 500 mg orally twice a day for 28 days versus a placebo. Rash development and severity (monthly physician assessment and weekly patient-reported questionnaires), quality of life (SKINDEX-16), and adverse events were monitored during the 4-week intervention and then for an additional 4 weeks. The primary objective was to compare the incidence of grade 2 or worse rash between study arms; 32 patients per group provided a 90% probability of detecting a 40% difference in incidence with a type I error rate of 0.05 (two-sided). Results: Sixty-five patients were enrolled, and groups were balanced on baseline characteristics. During the first 4 weeks, healthcare provider-reported data found that 27 tetracycline-treated patients (82%) and 24 placebo-exposed patients (75%) developed a rash. This rash was a grade 2+ in 17 (52%) and 14 (44%), respectively (p=0.62). Comparable grade 2+ rash rates were observed during weeks 5 through 8 as well as with patient-reported rash data throughout the study period. Quality of life was comparable across study arms, and tetracycline was well tolerated. Conclusion: Although previous studies suggest otherwise, this randomized, double-blinded, placebo-controlled study did not find that tetracycline lessened rash incidence or severity in patients who were taking EGFR inhibitors.