PURPOSE: The pharmacology, pharmacokinetics, and safety of gefitinib and its role in the management of non-small-cell lung cancer are reviewed. SUMMARY: Gefitinib is indicated for patients with locally advanced or metastatic non-small-cell lung cancer who have not responded to chemotherapy with platinum-based regimens or docetaxel. Gefitinib is administered orally at a dosage of 250 mg/day. Peak plasma levels are attained within 3-7 hours and steady-state levels are achieved in 7-8 days. Food does not affect the drug's absorption. Gefitinib is metabolized by the cytochrome P-450 isoenzyme system and may be affected by other drugs that influence this enzyme activity. Its elimination half-life is 14-48 hours. Clinical trials have shown an average response rate of 93% when gefitinib is used as a second- or third-line agent. Median survival with gefitinib therapy is 3-6.6 months. There was no response or survival benefit with the addition of gefitinib to standard two-drug combination chemotherapy regimens in two large, randomized, placebo-controlled trials. However, there is some evidence that the combination of gefitinib and docetaxel may be more active than docetaxel alone. Gefitinib has been shown to improve pulmonary symptoms and quality of life in patients who did not have an objective response to treatment. The most common adverse effects are diarrhea and skin rash. Severe interstitial lung disease, which may be fatal, occurs at a rate of approximately 1%. CONCLUSION: Gefitinib is active as a second- or third-line agent in patients who have few therapeutic options available after initial and first-line salvage chemotherapy have failed.
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