A Study of QL1706 Combined With Chemotherapy Induction on Sequential Immunotherapy Consolidation in Patients With Limited-Stage Small Cell Lung Cancer After Chemoradiotherapy

Prior treatment

• History of another primary malignancy or previous allogeneic organ transplantation.
• Surgery (other than diagnostic biopsy) within 4 weeks before first dose of study drug.
• Active autoimmune disease, or history of autoimmune disease likely to recur. Systemic corticosteroid therapy equivalent to \>10 mg/day prednisone (or other immunosuppressive therapies) within 14 days before first dose.
• Prior therapy with any antibody or agent targeting T-cell co-regulatory proteins (e.g., PD-1, PD-L1, CTLA-4, TIM-3, LAG-3).
• Live vaccine administration within 28 days prior to first study drug dose. Any condition or comorbidity contraindicating chemo- or radiotherapy (e.g., active infection, myocardial infarction within 6 months, symptomatic heart disease including unstable angina, congestive heart failure, uncontrolled arrhythmia, ongoing immunosuppressive therapy).

Other illness

• Known hypersensitivity to QL1706 or any of its excipients
• Histologically confirmed non-small cell lung cancer (NSCLC) or mixed tumor containing an NSCLC component.
• Active substance abuse (e.g., illicit drug use), chronic alcoholism, AIDS, or known HIV infection.
• Interstitial lung disease (ILD), or history of ILD requiring steroid therapy. History of idiopathic pulmonary fibrosis, drug-induced pneumonitis, organizing pneumonia (e.g., bronchiolitis obliterans), or evidence of active pneumonia on screening chest CT.
• Known hereditary bleeding diathesis or coagulation disorder.

Lab values

• Any other medical, psychiatric, or laboratory abnormality that, in the investigator's judgment, could interfere with trial participation or interpretation of results.

Age

• Prior malignancy, except adequately treated non-melanoma skin cancer, or in situ carcinoma (e.g., breast, oral, cervical) with expected survival \>3 years.

Other

• Pregnant or breastfeeding women; women of childbearing potential or men unwilling to use adequate contraception.

• The patient must be aged between 18 and 75 years (inclusive of boundary values), and both males and females are eligible.
• Pathologically confirmed LS-SCLC
• Investigator confirmation of at least one measurable lesion, as defined by RECIST v1.1
• ECOG performance status of 0 or 1
• Forced expiratory volume in one second (FEV₁) \> 1.0 L
• No clinically significant interstitial lung disease on baseline CT or PET/CT.
• Adequate organ and bone-marrow function (all tests performed within 7 days prior to first dose; no transfusions, growth factors, albumin, or other corrective therapies within 14 days):Hemoglobin ≥ 90 g/L, ANC ≥ 1.5 × 10⁹/L, PLT ≥ 90 × 10⁹/L,Serum creatinine ≤ 1.5 × ULN, TBIL ≤ 1.5 × ULN, ALT and AST ≤ 3 × ULN, Albumin (ALB) ≥ 25 g/L,INR ≤ 1.5 × ULN, PT and APTT ≤ 1.5 × ULN (subjects on prophylactic anticoagulation must have values within a safe therapeutic range, per investigator)
• Women of childbearing potential must have a negative serum or urine pregnancy test within 7 days prior to enrollment and agree to use reliable contraception from screening until 3 months after the last dose; male subjects must agree to use effective contraception or have undergone surgical sterilization for the same period.
• No prior systemic anti-tumor therapy before enrollment.
• Estimated life expectancy ≥ 12 weeks.