PD-L1 Inhibitor Combined With Apatinib as First-line Maintenance Treatment for Extensive-stage Small Cell Lung Cancer

This is a prospective, single-arm clinical study designed to evaluate the 6-month progression-free survival rate (6-month PFS rate) of a PD-L1 inhibitor combined with apatinib as first-line maintenance treatment for extensive-stage small cell lung cancer (ES-SCLC). The study plans to recruit 40 patients. After receiving 4-6 cycles of induction therapy, patients whose efficacy is evaluated as CR, PR or SD (according to RECIST 1.1) will enter maintenance therapy with PD-L1 inhibitor + apatinib 250 mg po qd. , the selection of PD-L1 inhibitors in the maintenance phase is consistent with the first-line standard treatment in the induction phase. Efficacy was assessed using RECISIT 1.1, with imaging evaluations every 6 weeks (±7 days) for 48 weeks after the first dose and every 9 weeks (±7 days) after week 48, regardless of treatment delays or interruptions, until Disease progression or study termination, whichever occurs first. The primary efficacy endpoint of this study is 6-month PFS rate, and secondary efficacy endpoints include median PFS, median OS and safety.