LEARNING OBJECTIVESAfter completing this course, the reader will be able to:1. Describe the molecular mechanism of action of erlotinib.2. Define clinical and molecular predictors of response to erlotinib.3. Describe the clinical trials performed with erlotinib in NSCLC and underline future clinical development of this drug in the treatment of NSCLC.Access and take the CME test online and receive 1 AMA PRA Category 1 Credit ™ at CME.TheOncologist.com CME CME
ABSTRACT
Approximately 213,380 new cases of non-small-cell lung cancer (NSCLC) were estimated to occur in the USA in 2007, which caused 160,390 NSCLC-related deaths. The majority of patients will be diagnosed with nonoperable, advanced-stage disease. Although combination chemotherapy remains the standard treatment, median survival with these regimens is only 8-10 months. Recent advances in our understanding of lung cancer on a molecular level have led to the introduction of targeted therapies. The EGF receptor (EGFR) was the first receptor to be proposed for cancer therapy and two EGFR-targeted pharmacologic approaches have been successfully developed: monoclonal antibodies (mAbs) and small-molecule inhibitors of the EGFR tyrosine kinase enzymatic activity. Erlotinib is a quinazoline derivative that selectively and reversibly inhibits the tyrosine kinase activity of the EGFR. Here, we review the mechanism(s) of action of erlotinib, as well as the results of Phase I, II and III trials with this drug in NSCLC, which have led to the worldwide approval of erlotinib treatment as monotherapy for therapy-refractory, advanced NSCLC patients.
More than 40% of cases of all lung cancers are diagnosed in patients over the age of 70 years. Elderly patients have more comorbidities and tend to be less tolerant to toxic medical treatments than their younger counterparts. Thus, clinical data obtained in a younger population cannot be automatically extrapolated to the great majority of nonselected elderly patients with non-small cell lung cancer (NSCLC). The bulk of prospective clinical data regarding chemotherapy and molecularly targeted therapy for elderly NSCLC patients come from studies in advanced disease. In elderly advanced NSCLC patients, single-agent chemotherapy with third-generation agents (vinorelbine, gemcitabine, taxanes) is to be considered the routine standard of care for unselected patients, based on phase II and III trials specifically designed for this special population. Cisplatin-based chemotherapy with cisplatin at attenuated doses has been demonstrated to be an active and feasible option in phase II trials. Among targeted therapies, the epidermal growth factor receptor tyrosine kinase inhibitors, erlotinib and gefitinib, have relevant phase II prospective data showing activity and good tolerability as first-line treatment in this population. Concerning the antivascular endothelial growth factor monoclonal antibody, bevacizumab, combined with chemotherapy, particular care must be taken for elderly patients because of the higher incidence of cardiovascular comorbidities. The lack of data on octogenarians suggest that clinicians should exercise caution when applying the existing data on chemotherapy and targeted therapies for patients aged 70-79 years to those aged >80 years. Further specifically designed clinical trials are needed to optimize medical treatment of NSCLC in elderly patients.
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