Efficacy and Safety Study of Bevacizumab Plus Chemotherapy in EGFR-TKI Resistant Non-Squamous Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) tyrosine kinase is one of most popular target molecules in the field of anticancer drug research. EGFR is highly expressed in many types of tumor cells, which could activate EGFR cytosolic kinase activity by binding to its ligand EGF, and regulates gene expression, cell proliferation, differentiation, apoptosis through different signal transduction pathways. Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), competitive to specifically combined with the EGFR kinase domain, thus inhibits its kinase activity, thereby blocking cancer cell proliferation or metastasis. At present, EGFR-TKI has been widely used in clinical activity, especially in patients with EGFR mutations, which had been proved to achieved a certain effect. But with the passage of time, a drug resistance is inevitable. At present, studies have found that the cessation of treatment immediately after EGFR-TKI resistance may lead to rapid progress of cancer. Chemotherapy, as one of the most widely accepted modality in cancer treatment, might also be one of the salvage therapies of target treatment. Therefore, in patients with better physical status (PS) scores, chemotherapy is commonly applicable. In January 2010, a study published in the journal of Clinical Lung Cancer reported the application of chemotherapy as salvage treatment for advanced non-small cell lung cancer (NSCLC) patients with resistant to first-line EGFR-TKI treatment. Of the 114 patients enrolled, 67 received sequential chemotherapy, the other 47 patients received best supportive care. The results showed that, sequential chemotherapy can improve the survival time of the patients, compared with chemotherapy and supportive care groups (11.2 months vs. 3.8 months, P\< 0.01). Furthermore, in those who received sequential chemotherapy, a regimen containing paclitaxel got higher efficiency and disease control rate than those without (48.7% vs. 21.4%, 79.5% vs. 53.5% , P\< 0.05), as w