Pooled analysis of the reports of erlotinib after failure of gefitinib for non-small cell lung cancer.

Purpose: The use of erlotinib after gefitinib failure in patients with non-small cell lung cancer (NSCLC) is not clearly clarified in clinical practice. We sought to compile the available clinical reports to better understand the effectiveness of erlotinib after failure of gefitinib.
Methods: We searched published reports including erlotinib and gefitinib. Eleven reports were identified (published between November 2004 and December 2008). Advanced NSCLC who documented progressive disease (PD) for gefitinib 250 mg/day, received erlotinib 150 mg once daily.
Results: A total of 106 patients were pooled from these studies. Asian was observed in 70.8%, women in 72.6%, adenocarcinoma in 85.1%, never smoker in 75.3%. In erlotinib therapy, there was observed in 9.9% in partial response (PR), 18.9% in stable disease (SD) and 70.8% in PD. Disease control (DC) rate for gefitinib and erlotinib was 71.7% and 29.2%, respectively. No significant difference of disease control rate (37.5% vs 21.7%, p=0.1503) and response rate (6.3% vs 8.7%, p=1.000) was observed between patients with EGFR mutations and those with wild type EGFR. The significantly different response on erlotinib therapy was observed in patients who had shown SD for gefitinib therapy (p=0.0095) and those who had a PFS of more than 6 months during gefitinib treatment (p=0.0261). The common toxicities were skin rash and diarrhea.
Conclusion: Erlotinib may produce clinical benefits in patients who had shown long SD on prior gefitinib therapy. Moreover, EGFR mutations were not positive predictors for erlotinib response after gefitinib failure.
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