Adebrelimab Plus Apatinib for Maintenance Therapy of Extensive Stage Small Cell Lung Cancer

This is a prospective, single-arm trial. To evaluate the efficacy and safety of maintenance therapy with Adebrelimab plus Apatinib for extensive stage small cell lung cancer after first-line induction of Adebrelimab plus chemotherapy.

Induction Period: Participants received adebrelimab (1200 mg, iv., Day1) + carboplatin (AUC 4-5 mg/mL/min)/cisplatin (75 mg/m2) + etoposide (100 mg/m2, D1-3) for 4-6 cycles of three weeks.

Maintenance phase: Participants received adebrelimab (1200mg, iv., Day1) + apatinib (250mg, po., daily) once every three weeks.

Follow-up: After disease progression, at the discretion of the investigator, apatinib and adebrelimab can be used across lines:

For platinum-sensitive patients (≥3 months from last chemotherapy): apatinib and adebrelimab plus platinum-containing two-agent chemotherapy (irinotecan/purple shirts in combination with platinum); for patients with PFS1 \>12 months: chemotherapy can be continued with the original EC/EP regimen; For platinum-resistant patients (\<3 months from last chemotherapy): apatinib and adebrelimab plus concurrent single-agent chemotherapy (irinotecan or single-agent purple shirts). The dose of chemotherapy agents was adjusted empirically by the investigators.

The primary endpoint is progression-free survival (PFS). Secondary endpoints include objective remission rate (ORR), disease control rate (DCR), duration of remission (DoR), and overall survival (OS); PFS2 (defined as time from enrolment to second disease progression or death) Our study will also explore biomarkers including: haematopoietic factors (IL-6,IL-8, IL-10, etc.), PD-L1 expression, T-cell subsets, T-cell immunoprecision typing and regulatory T-cell counts. The data from our study will provide the basis for further prospective clinical trials (Phase III).