Experience with erlotinib in the treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related deaths. In the last decade, the epidermal growth factor receptor (EGFR) signalling pathway has emerged as one of the most important molecular aberrations, representing an attractive therapeutic target in NSCLC. Drugs interfering with the tyrosine kinase domain of the EGFR (EGFR TKIs), such as erlotinib and gefitinib, have demonstrated efficacy in patients with advanced NSCLC irrespective of therapy line and particularly in patients harbouring activating mutations in the EGFR gene (EGFR(mut+)). Results of large phase III randomized trials clearly established that EGFR TKIs are superior to chemotherapy as frontline treatment in patients with EGFR(mut+), whereas in the EGFR wild-type (EGFR(WT)) or EGFR unknown population, platinum-based chemotherapy remains the standard of care, with no consistent benefit produced by the addition of EGFR TKI. In pretreated NSCLC, EGFR TKIs are considered more effective than standard monotherapy with cytotoxics in the presence of classical EGFR mutations, whereas in the EGFR(WT) population, a similar efficacy to docetaxel or pemetrexed in terms of survival has been demonstrated. Unfortunately, patients who initially responded to EGFR TKIs invariably develop acquired resistance. For such patients there is an urgent need for more effective strategies able to delay or possibly overcome resistance. In the present review we analysed the available data on erlotinib in the treatment of advanced NSCLC.