Epidermal growth factor receptor (EGFR) expression has been associated with clinical outcome in some studies of renal-cell carcinoma (RCC). We investigated the efficacy and safety of gefitinib (IRESSA), an EGFR tyrosine kinase inhibitor, in RCC patients. This phase II trial recruited 28 patients with advanced, metastatic, or relapsed RCC. Patients received oral gefitinib 500 mg/day. Objective responses (ORs) were assessed every 2 months according to RECIST. Baseline tumor biopsies were analyzed immunohistochemically for EGFR expression. At trial closure (March 2003), no ORs were seen but 14 patients (53.8%) had stable disease. At extended analysis (August 2004), median time to progression was 110 days (95% confidence interval [CI]: 55, 117); median overall survival was 303 days (95% CI 180, 444). Gefitinib was generally well tolerated. Skin rash and diarrhea were the most common drug-related adverse events (AEs) [54 and 39% of patients, respectively] and the most common drug-related grade 3/4 AEs (both 11%). The majority of tumor biopsies (91%) had > or =70% of tumor cells expressing membrane EGFR. Despite the lack of ORs in this study, disease control was observed in 53.8% of patients. Gefitinib was generally well tolerated and no unexpected drug-related AEs were observed.