Background: Both gefitinib and erlotinib are reversible epidermal growth factor receptor tyrosine kinase inhibitors, but they have somewhat different pharmacological properties. We conducted a phase II study of erlotinib after failure of gefitinib treatment in patients with non-small-cell lung cancer (NSCLC).
Patients and methods: Patients with advanced/metastatic NSCLC who had shown disease progression on gefitinib treatment were treated with erlotinib 150 mg/day until disease progression or intolerable toxicity.
Results: Between September 2006 and January 2008, a total of 23 patients were enrolled and all were assessable for response and toxicity. All patients were never smokers and all but one had adenocarcinoma. Of these 23 patients, one had a partial response and one stable disease, resulting in an objective response rate of 4.3% and a disease control rate of 8.7%. These two patients benefited from erlotinib for 6.2 months and 7.8 months, respectively; both had also benefited from prior gefitinib therapy. The most common toxic effects were skin rash and diarrhea.
Conclusion: Erlotinib should not be given routinely after failure of gefitinib treatment, but can be an option for more highly selected subsets, especially those who had benefited from prior gefitinib treatment. Identification of molecular markers in tumors is important to understand and overcome acquired resistance to gefitinib.