Advances in Target Therapy for Lung Cancer

Recent progress in molecular biology has shown that cancer cells acquire common phenotypes such as self-sufficiency of growth signals, resistance to anti-proliferative and apoptotic signals through the accumulation of genetic and epigenetic changes. Recently developed anticancer drugs target these molecular mechanisms and good results have been reported for various cancer types. In lung cancer, tyrosine kinase inhibitors specific for the epidermal growth factor receptor such as gefitinib and erlotinib have changed clinical practice dramatically. About half of the Japanese patients with lung cancers harbor an activating mutation of the epidermal growth factor receptor gene and they are very sensitive to epidermal growth factor receptor tyrosine kinase inhibitors. Progression-free survival of such patients is similar to 10 months when treated with gefitinib, whereas the survival for those treated with platinum doublet therapy is similar to 6 months. Target therapies against echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion protein or a mutated ERBB2 (v-ERB-B avian erythroblastic leukemia viral oncogene homologue 2) present in similar to 5% and similar to 3% of the Japanese patients with adenocarcinomas, respectively, are currently under development. Addition of an anti-epidermal growth factor receptor antibody, cetuximab, or anti-vascular endothelial growth factor antibody, bevacizumab, to platinum doublet therapy significantly but modestly prolonged the survival in recent clinical trials. However, clinical development of small molecule multi-kinase inhibitors including those targeting vascular endothelial growth factor receptors, such as vandetanib, sunitinib and sorafenib, has not been very successful. Through these collaborations among clinicians, basic researchers and pharmaceutical companies, it should be possible to individualize lung cancer treatment to turn this fatal disease into a chronic disorder and, eventually, to cure it.