Abstract
BACKGROUND: With the first and second-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), clinical benefit and rash correlate together. EGFR TKI-induced rash can be alleviated with tetracyclines, but it is unknown whether the use of tetracyclines can increase the survival of non-small-cell lung cancer (NSCLC) patients treated with EGFR TKIs. METHODS: We collected all the patients (n=1271) who had reimbursement for EGFR TKIs (gefitinib, erlotinib and afatinib) in Finland 2011-2016, had purchased TKIs, and had data available at nationwide cancer registry. The survival was analysed from the first EGFR TKI purchase to death or end-of follow-up, and patients were stratified according to TKIs, purchases of antibiotics, their ATC class and timing. RESULTS: 802 (63.1%) patients had antibiotic purchases -14 to +200 days from the first EGFR TKI purchase, 447 of these tetracyclines. 322 (25.3%) had had purchased antibiotics -14 to +14 days (prophylaxis) from the first EGFR TKI purchase, 188 of these tetracyclines. Purchase of antibiotics was associated with improved survival (HR 0.80, 95% CI 0.71 to 0.91), which limited to tetracycline purchases only (HR 0.72, 95% CI 0.64 to 0.82). The largest survival benefit was seen with the prophylactic use of tetracyclines (HR 0.74, 95% CI 0.62 to 0.88). The benefit from tetracyclines was limited to erlotinib only (HR 0.68, 95% CI 0.58 to 0.78) which was retained in multivariate analysis. Prophylactic use of tetracyclines was associated with a longer erlotinib treatment duration (HR 0.81, 95% CI 0.61 to 0.96) but not with dose reductions or treatment breaks. CONCLUSIONS: Tetracyclines improve the survival of NSCLC patients treated with the first and second-generation EGFR TKIs and they should be considered as a prophylaxis when initiating EGFR TKIs with high incidence of rash.