Blood test may predict who benefits from lung cancer combo therapy

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Histologically or cytologically confirmed stage IIIB-IV non-small cell lung cancer (NSCLC) * Planned to receive PD-1 inhibitor combined with platinum-based chemotherapy (e.g., pembrolizumab + pemetrexed/carboplatin) * Age 18-80 years * ECOG performance status 0-1 * Expected survival ≥12 weeks * Adequate bone marrow function: ANC ≥1.5×10⁹/L, PLT ≥100×10⁹/L * Adequate hepatorenal function: Cr ≤1.5×ULN, ALT/AST ≤2.5×ULN * At least one measurable lesion per RECIST 1.1 criteria * Able to provide informed consent and comply with study procedures including serial blood sampling and imaging follow-up Exclusion Criteria: * No measurable disease per RECIST 1.1 criteria * Tumor emergencies requiring immediate intervention (spinal cord compression, superior vena cava syndrome) * Active untreated central nervous system metastases or leptomeningeal disease * Prior treatment with immune checkpoint inhibitors within 4 weeks before enrollment * Chronic use of immunosuppressive agents (e.g., corticosteroids \>10 mg/day prednisone equivalent) * Coagulation disorders (INR \>1.5 or APTT \>1.5×ULN) or ongoing anticoagulation therapy * Poor vascular access precluding serial venipuncture (\>5 mL per draw) * Active hepatitis B (HBV DNA \>2000 IU/mL), hepatitis C, or HIV infection * Uncontrolled bacterial or fungal infection requiring systemic treatment * Pregnancy or lactation * Severe psychiatric disorder or communication barriers affecting informed consent or follow-up compliance Withdrawal Criteria: * Participant voluntary withdrawal with signed withdrawal statement * Major protocol violations: failure to receive ≥2 cycles of planned chemoimmunotherapy; missing ≥2 critical timepoint blood samples (baseline, cycle 2) * Uncontrollable grade ≥3 immune-related adverse events requiring permanent discontinuation of PD-1 inhibitor Study Termination Criteria: * Disease progression confirmed by imaging per RECIST 1.1 or clinical progression requiring radiotherapy * Death or loss to follow-up \>6 months * Unacceptable grade 4 treatment-related toxicity * Investigator determination that continued participation poses health risk to patient * Study terminated by ethics committee for scientific or administrative reasons