A Phase II Study of QL1706 With Anti-angiogenesis Therapy and Chemotherapy in Extensive-stage Small Cell Lung Cancer.

Participants will receive QL1706 (5 mg/kg, IV, day 1), bevacizumab (7.5 mg/kg, IV, day 1), etoposide (100 mg/m², IV, days 1-3), plus either cisplatin (75 mg/m² split over days 1-2, IV) or carboplatin (AUC=5, IV, day 1) every 21 days for 4-6 cycles. Dose adjustments may be made based on clinical judgment. Patients who do not experience disease progression or intolerable toxicity will proceed to maintenance therapy with QL1706 (5 mg/kg, IV, day 1) and bevacizumab (7.5 mg/kg, IV, day 1) every 21 days, continued until disease progression, unacceptable toxicity, consent withdrawal, investigator decision, loss to follow-up, death, or other protocol-defined criteria. All participants will receive dual-agent maintenance therapy.