Anlotinib Combined with S-1 in the Third-Line Treatment of Stage IV Non-Small Cell Lung Cancer: Study Protocol for Phase II Clinical Trial

Background: A proportion of patients with stage IV non-small-cell lung cancer (NSCLC) is predicted to receive third-line treatment. However, currently no standard third-line treatment for NSCLC is available. Anlotinib is an oral, multi-targeted tyrosine kinase (TK) receptor inhibitor, which was approved as a third-line treatment for stage IV NSCLC in China on May 9, 2018. Nevertheless, The objective response rate of patients treated with anlotinib was merely 9.2% and the overall survival was only 3 months compared with the patients treated with placebo. Previous studies have shown that cancer treatment with a combination of chemotherapy with TK receptor inhibitors is effective and safe well tolerated. Therefore, the combination of anlotinib with other chemotherapeutic agents may be an effective treatment strategy for patients with stage IV NSCLC. Oral S-1 is a third-generation fluorouracil derivative; it showed good efficacy and caused relatively low toxicity in patients with NSCLC. Methods: The purpose of this trial is to evaluate the efficacy and safety of anlotinib combined with S-1 as the third-line treatment for patients with stage IV NSCLC. This is a prospective, phase II clinical trial. We will enroll29 patients with stage IV NSCLC treated with anlotinib plus S-1. Tumors will be assessed using computed tomography prior to treatment, after two, four, and six cycles of treatment, and during follow-up every 3 months until disease progression or death. The primary endpoint is the objective response rate (ORR). The secondary endpoints are progression-free survival, duration of response, proportion of disease control, and safety. Discussion: The expected outcome of this study is that anlotinib combined with S-1 has tolerable toxicity and better ORR than anlotinibmonotherapy. The results may indicate additional treatment options for patients with stage IV NSCLC.