Opinion statement Gefitinib is a small molecule that specifically inhibits the tyrosine kinase
activity of the epidermal growth factor receptor (EGFR) type 1 by interfering with the
adenosine triphosphate (ATP) binding site. At doses that maximally inhibit EGFR tyrosine
kinase activity chosen for phase II trials, the most common side effects of gefitinib are low-
grade rash or diarrhea. An infrequent but serious side effect of gefitinib is interstitial lung
disease (ILD). The Iressa dose evaluation for advanced lung cancer phase II trials (IDEAL 1 …

Gefitinib is an oral, reversible, tyrosine kinase inhibitor of epidermal growth factor receptor
(EGFR) that plays a key role in the biology of non small cell lung cancer (NSCLC). Phase I
studies indicated that the recommended dose of gefitinib was 250 mg/day. Rash, diarrhea,
and nausea were the most common adverse events. The positive results obtained in early
phase 2 clinical trials with gefitinib were not confirmed in large phase 3 trials in unselected
patients with advanced NSCLC. The subsequent discovery that the presence of somatic …