Evaluation of Three Small Molecular Drugs for Targeted Therapy to Treat Nonsmall Cell Lung Cancer

OBJECTIVE: To guide the optimal selection among first-generation epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in clinical practice. This review attempted to provide a thorough comparison among three first-generation EGFR-TKIs, namely icotinib, erlotinib, and gefitinib, with regard to their molecular structure, pharmacokinetic parameters, clinical data, adverse reactions, and contraindications. DATA SOURCES: An electronic literature search of the PubMed database and Google Scholar for all the available articles regarding gefitinib, icotinib, and erlotinib in the English language from January 2005 to December 2014 was used. STUDY SELECTION: The search terms or keywords included but not limited to “lung cancer”, “nonsmall cell lung cancer (NSCLC)”, “epidemiology”, “EGFR”, “TKIs”, and “optimal selection”. RESULTS: As suggested by this review, even though the three first-generation EGFR-TKIs share the quinazoline structure, erlotinib had the strongest apoptosis induction activity because of its use of a different side-chain. The pharmacokinetic parameters indicated that both erlotinib and icotinib are affected by food. The therapeutic window of erlotinib is narrow, and the recommended dosage is close to the maximum tolerable dosage. Icotinib enjoys a wider therapeutic window, and its concentration in the blood is within a safe dosage range even if it is administered with food. Based on multiple large-scale clinical trials, erlotinib is universally applied as the first-line treatment. In marked contrast, icotinib is available only in China as the second- or third-line therapeutic approach for treating advanced lung cancer. In addition, it exhibits a similar efficacy but better safety profile than gefitinib. CONCLUSIONS: Although there is a paucity of literature regarding whether icotinib is superior to erlotinib, its superior toxicity profile, noninferior efficacy, and lower cost indicate that it is a better alternative for Chinese patients living with advanced NSCLC.