Study on the Therapeutic Effect of Irinotecan Liposomes in Small Cell Lung Cancer

Inclusion Criteria: * The patient fully understands this study, voluntarily participates and signs an informed consent form (ICF). * Age ≥ 18 years old; * Patients with extensive stage small cell lung cancer diagnosed by pathology or histology; * According to RECIST 1.1 standard, patients have at least one measurable target lesion; For lesions that have undergone radiation therapy in the past, they can only be included as measurable lesions if there is clear disease progression after radiation therapy; * Progression confirmed by imaging examination after 6 months of first-line radiotherapy and chemotherapy containing platinum drugs or platinum regimen radiotherapy and chemotherapy ± immunotherapy; * Eastern Cancer Collaborative Group (ECOG) physical fitness score: 0-2 points; * Estimated survival time ≥ 3 months; * Absolute neutrophil count (ANC) ≥ 1.5 x 10 \^ 9/L, platelet count ≥ 90 x 10 \^ 9/L, and hemoglobin count ≥ 90 g/L (no blood transfusion, blood products, use of granulocyte colony-stimulating factor or other hematopoietic stimulating factor correction within 14 days prior to laboratory examination); * Liver and kidney function: serum creatinine ≤ 1.5 times the upper limit of normal value; AST and ALT ≤ 2.5 times the upper limit of normal values (≤ 5 times the upper limit of normal values for patients with liver invasion); Total bilirubin ≤ 1.5 times the upper limit of normal value (≤ 3 times the upper limit of normal value for patients with liver invasion); * Women of childbearing age must undergo a pregnancy test (serum) within 7 days before enrollment, and the result is negative. They are willing to use appropriate methods of contraception during the trial period and 6 months after the last administration of the trial drug; Exclusion Criteria: * Patients with large cell neuroendocrine tumors and mixed small cell carcinoma; * Patients with active brain metastasis or central nervous system invasion confirmed by imaging evaluation and/or biopsy (prednisone equivalent dose ≥ 10mg); * There is an hypersensitivity reaction to any investigational drug or its components; * Severe uncontrolled concurrent infections or other serious uncontrolled concomitant diseases, moderate or severe kidney injury; (such as progressive infection, uncontrollable hypertension, diabetes, etc.); * Heart function and disease meet one of the following conditions: 1. Long QTc syndrome or QTc interval\>480 ms; 2. Complete left bundle branch block, II or III degree atrioventricular block; 3. Severe and uncontrolled arrhythmias that require medication treatment; 4. The New York College of Cardiology has a classification of ≥ III; 5. Cardiac ejection fraction (LVEF) below 50%; 6. A history of myocardial infarction, unstable angina, severe unstable ventricular arrhythmias, or any other arrhythmias requiring treatment, a history of clinically severe pericardial disease, or evidence of acute ischemic or active conduction system abnormalities on electrocardiogram within the 6 months prior to recruitment. * Active infection of hepatitis B and hepatitis C (hepatitis B B virus surface antigen is positive and hepatitis B B virus DNA exceeds 1x103 copies/mL; hepatitis C virus RNA exceeds 1x103 copies/mL); * Human Immunodeficiency Virus (HIV) infection (HIV antibody positive); * Has previously or currently suffered from other malignant tumors (except for effectively controlled non melanoma skin basal cell carcinoma, breast/cervical carcinoma in situ, and other malignant tumors that have not been treated and have been effectively controlled within the past five years); * Pregnant and lactating women, as well as patients of childbearing age who are unwilling to take contraceptive measures; * Patients with other malignant tumors that require treatment; The researchers determined that patients who are not suitable to participate in this study.