Allogeneic NK Cell Therapy Combined With Standard Maintenance Treatment in Advanced Solid Tumors

This is a prospective, open-label, exploratory clinical study to evaluate the safety and preliminary efficacy of allogeneic natural killer (NK) cell injection combined with standard maintenance therapy in patients with locally advanced or metastatic solid tumors. The study consists of three cohorts: Cohort 1 (advanced non-squamous NSCLC with NK cells + PD-(L)1 inhibitor + pemetrexed), Cohort 2 (advanced colorectal adenocarcinoma with NK cells + cetuximab/bevacizumab + capecitabine), and Cohort 3 (lymphodepletion exploration cohort with fludarabine + cyclophosph preconditioning followed by NK cells + PD-(L)1 inhibitor + pemetrexed).

Inclusion Criteria: 1. Age 18-75 years, either gender 2. Cohort 1 \& 3: Histologically or cytologically confirmed locally advanced unresectable or metastatic non-squamous NSCLC (Stage IIIB-IV) without known actionable driver gene mutations (including but not limited to: EGFR sensitizing mutations, ALK rearrangement, ROS1 rearrangement, BRAF V600E mutation, KRAS mutation) 3. Cohort 1 \& 3: Previously received 4-6 cycles of first-line induction therapy with PD-(L)1 inhibitor combined with pemetrexed plus platinum, with radiographic assessment of non-progressive disease (CR, PR, or SD per RECIST 1.1) 4. Cohort 2: Histologically or cytologically confirmed locally advanced unresectable or metastatic colorectal adenocarcinoma (unresectable Stage III or Stage IV per AJCC 8th edition) 5. Cohort 2: Previously received 6-9 cycles of first-line induction therapy with cetuximab or bevacizumab combined with FOLFOX or FOLFIRI, with radiographic assessment of non-progressive disease (CR, PR, or SD per RECIST 1.1) 6. Prior neoadjuvant/adjuvant chemotherapy allowed if disease recurrence or metastasis occurred \>6 months after last chemotherapy dose 7. At least one measurable lesion per RECIST 1.1 (except patients who achieved CR during induction therapy): non-lymph node lesion ≥1.0 cm in longest diameter, or lymph node lesion ≥1.5 cm in short diameter; lesions treated with local therapy (radiation or interventional) cannot be target lesions unless progression is documented 8. Adequate bone marrow and organ function: 1. ANC ≥1.5×10⁹/L; Platelet \>90×10⁹/L; Hemoglobin \>9 g/dL 2. Liver function: Total bilirubin \