Most patients with extensive disease small cell lung cancer (ED-SCLC) respond to first line（1L） platinum-based chemotherapy; however, responses are not durable and prognosis is poor. Currently no maintenance treatments are approved in SCLC to prolong the durability of efficacy achieved with 1L chemotherapy. Immuno-oncology agents have demonstrated efficacy in the treatment of ED-SCLC when administered across different lines of therapy. Tislelizumab (Anti-PD-1 antibody) Combine Etoposide+ platinum （EP） had improved median Overall survival （mOS ） to 15.6m of 1L ED-SCLC in the Rationale 206 study. Anlotinib ( RTKi ) had significantly improved PFS & OS of 3L(third line) ED-SCLC in the ALTER 1202. This phase II study is designed to explore the effect and safety of the combination as maintenance therapy for ED-SCLC after 1L chemotherapy
To show that maintenance therapy with Tislelizumab plus Anlotinib will prolong Progression Free Survival in subjects with extensive stage disease small cell lung cancer who have completed first line chemotherapy.