[Comparative evaluation of adverse reactions between gefitinib and erlotinib treatments in the same patients].

ABSTRACT

Gefitinib is an orally active, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that is widely used in the treatment of advanced non-small-cell lung cancer (NSCLC). Erlotinib, which has the same mechanism of action as gefitinib, has been recently approved in Japan. We retrospectively investigated the adverse reactions in 16 patients who had received erlotinib after failure of gefitinib treatment. We examined the adverse reactions that occurred during gefitinib or erlotinib treatment using an electronic chart system. Anorexia was more frequent with erlotinib than with gefitinib treatment. Further, anorexia and diarrhea were significantly more severe with erlotinib than with gefitinib treatment. Most adverse reactions developed earlier during the course of erlotinib treatment than during the course of gefitinib treatment. In one patient who had received gefitinib treatment without pulmonary toxicity, erlotinib had to be discontinued due to the development of interstitial pneumonia. Our findings suggest that adverse reactions such as anorexia and diarrhea should be carefully monitored soon after starting erlotinib in advanced NSCLC patients in whom gefitinib treatment has been ineffective, because these reactions will occur sooner and would be more severe in erlotinib treatment.