Background: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are now key agents in treating EGFR-mutant non-small cell lung cancer (NSCLC). The efficacy of gefitinib or erlotinib monotherapy can be predicted by the development of a skin rash. However, it has not been fully evaluated if this is the case with afatinib monotherapy.
Methods: We retrospectively studied 49 consecutive patients with EGFR-mutant NSCLC who received afatinib therapy between 2009 and 2015. The relationship of several toxicities with tumor response was examined.
Results: Grade 2, or more severe, common adverse events (AEs) included skin rash in 17 patients (35 %), diarrhea in 19 (39 %) and mucositis in 15 (31 %). Of these, the number of patients who developed ≥Grade 2 AEs during the first week after the initiation of afatinib therapy was: five patients had skin rash (10 %), 12 patients had diarrhea (25 %) and four patients had mucositis (8 %). As for an objective response, 21 (43 %) of the 49 had a partial response. Associating the AEs with the antitumor effect, those who had a ≥Grade 2 skin rash within the first week tended to have a greater tumor response compared with those without a rash (80 vs. 39 %; p = 0.077).
Conclusion: Our small study demonstrated that the early development of a skin rash might be associated with the response to afatinib monotherapy.
Keywords: Afatinib; Lung cancer; Response; Skin rash.