Gefitinib (Iressa, ZD1839): a novel targeted approach for the treatment of solid tumors.

Recent advances in cancer therapy have resulted in the development of drugs that target mechanisms involved in neoplastic change and angiogenesis. One example is gefitinib ('Iressa', ZD1839), an orally-active epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that blocks EGFR signaling in vitro, thereby inhibiting the growth, proliferation and survival of many solid tumors. Clinical trial data show that gefitinib monotherapy is generally well tolerated in patients with a wide range of tumor types (including lung, head and neck, colon, breast, and prostate cancers). The most common adverse events (AEs) were mild and reversible skin and gastrointestinal disorders (National Cancer Institute common toxicity criteria grade 1/2). Few drug-related grade 3/4 skin and gastrointestinal disorders were observed, and drug-related hematologic AEs were uncommon. The clinical benefit of gefitinib in non-small-cell lung cancer (NSCLC), head and neck, colon, breast, and prostate cancer is being investigated, as antitumor activity has been observed in a range of solid tumors, including NSCLC. In two large phase II NSCLC trials (IDEAL ['Iressa' Dose Evaluation in Advanced Lung Cancer] 1 and 2) objective tumor responses of 18.4% and 11.8%, and disease control rates (complete and partial responses plus stable disease) of 54.4% and 42.2%, respectively, were seen in patients given 250 mg/day gefitinib. Additionally, disease-related symptoms improved in 40.3% and 43.1% of patients, and improved quality of life was experienced by 23.9% and 34.3% patients in IDEAL 1 and 2, respectively. Furthermore, the majority of patients who had an objective response also experienced symptom improvement. Gefitinib has been approved for the treatment of advanced NSCLC in Japan, the USA, and other countries. This review discusses the potential of gefitinib in a wide range of solid tumors. 'Iressa' is a trademark of the AstraZeneca group of companies.