Multi-centered, Single-arm, Phase II Study on Surufatinib in Combination of Durvalumab and Etoposide and Carboplatin/Cisplatin in the Firstly-line Treatment of Extensive-stage Small-cell Lung Cancer

BACKGROUND: Small-cell lung cancer (SCLC) is an aggressive neuroendocrine tumor derived from bronchial epithelial cells, accounting for about 13-15% of all lung cancers. It has a rapid doubling time and high growth fraction, and tends to metastasize widely early in the course of the disease, resulting in 95% mortality. It is the most lethal subtype of lung cancer. Platinum-based chemotherapy is the first-line standard treatment for localized and extensive SCLC, with platinum combined with etoposide as the preferred regimen. However, chemotherapy options are limited and there remains a great unmet need for efficacy. In recent years, with the development of immunotherapy, chemotherapy combined with immunization has also become the treatment option for treatment-naïve patients, and PD-L1 inhibitor combined with chemotherapy first-line treatment has become a guideline class 1A recommendation; there is a significant benefit in OS compared with chemotherapy: in the IMpower 133 study, atezolizumab combined with EP regimen resulted in an OS of 12.3 months; in the CASPIAN study, Durvalumab combined with EP/EC regimen resulted in an OS of 13 months. An increasing number of targeted therapeutics have also been newly explored in the field of SCLC. In first-line treatment, PFS reached 9.6 months, OS reached 13.87 months, and ORR reached 77.8% with anlotinib in combination with EP/EC regimen. Though great progress has been made in the treatment of SCLC in recent years, only two PD-L1 therapies are currently approved, treatment options are limited, and patient survival remains to be further improved. The current study aims to investigate the efficacy and safety of surufatinib combined with durvalumab combined with EP/EC regimen in first-line treatment of patients with extensive-stage SCLC, and to further explore the predictive biomarkers of this treatment combination.