NK Cells Plus ICI for SCLC Maintenance

This research study is designed for patients with extensive-stage small cell lung cancer (ES-SCLC) who have already received four cycles of standard chemotherapy, with at least two cycles combined with immunotherapy, and have achieved disease control (stable disease, partial response, or complete response) at their last efficacy evaluation. In this study, participants will be randomly assigned to one of two groups: Group A will receive standard immunotherapy plus 1 to 3 courses of allogeneic natural killer (NK) cell therapy. Each course consists of six NK cell infusions given over 28 days. Group B will receive standard immunotherapy alone. All participants will continue treatment until their disease progresses or they experience unacceptable side effects. The immunotherapy agents used in this study are those recommended by major international and national clinical guidelines for extensive-stage SCLC, including but not limited to durvalumab, atezolizumab, serplulimab, and adebrelimab. The purpose of this study is to evaluate whether adding NK cell therapy to standard immunotherapy can provide additional benefits for patients with extensive-stage SCLC who have responded well to initial treatment.

Inclusion Criteria: * 1: Male or female, aged 18 years or above 2: ECOG score 0-2 3: metastatic or extensive-stage small cell lung cancer (SCLC) confirmed by histology or cytology, followed by 4 cycles of platinum-based doublet-chemotherapy with at least 2 cycles of immune checkpoint inhibitor plus chemotherapy. And stable disease (SD), partial response (PR), or complete response (CR) as assessed by imaging (RECIST1.1 criteria) after the last treatment. (The checkpoint inhibitors used were those recommended by the NCCN, ESMO, and CSCO guidelines for extensivestage SCLC, including but not limited to: Duvalumab, atezolizumab, slulizumab, adbelimumab, toripalimab, etc.) 4: After standard concurrent chemoradiotherapy, LS-SCLC could be enrolled in this study if sensitive relapse (relapse more than 6 months after the end of first-line treatment) progressed to extensive-stage (Ed) and met the inclusion criteria No.3; 5: At least 4 weeks after major surgery or trauma, and the wound must be completely healed; At least 1 week after minor surgical procedures or trauma (e.g., tissue biopsy or fine-needle aspiration); 6: Objective measurable lesions according to RECIST 1.1 criteria; 7: predicted survival time ≥1 year; 8: bone marrow function: ANC≥1.5×109/L, HB≥70 g/L (blood transfusion allowed), PLT≥80×109/L; 9: Liver function: ALT≤3×ULN, AST≤3×ULN, TBIL≤2×ULN (patients with liver metastasis ALT≤5×ULN, AST≤5×ULN, TBIL≤2×ULN) Child-Pugh score ≤7; Renal function: uric acid \