A Study Comparing BL-B01D1 Combined With Tislelizumab Versus Platinum-containing Chemotherapy Combined With Tislelizumab as First-line Treatment in Patients With Extensive-stage Small Cell Lung Cancer(PANKU-Lung07)

Inclusion Criteria: 1. Voluntarily sign the informed consent form and comply with the protocol requirements; 2. Age ≥ 18 years; 3. Expected survival time ≥ 3 months; 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1; 5. Patients with histopathologically and/or cytologically confirmed extensive-stage small cell lung cancer; 6. Agree to provide archived tumor tissue specimens from the primary or metastatic lesions within 3 years, or fresh tissue samples; 7. Must have at least one measurable lesion as defined by RECIST v1.1; 8. Toxicity from prior anti-tumor therapy must have recovered to ≤ Grade 1 as defined by NCI-CTCAE v5.0; 9. No severe cardiac dysfunction, with left ventricular ejection fraction ≥ 50%; 10. Organ function levels must meet the requirements; 11. Urinary protein ≤ 2+ or \< 1000 mg/24h; 12. For premenopausal women of childbearing potential, a pregnancy test must be performed within 7 days before starting treatment, and the serum pregnancy test must be negative; patients must not be breastfeeding. All enrolled patients (regardless of male or female) must use adequate barrier contraception throughout the entire treatment period and for 6 months after the end of treatment. Exclusion Criteria: 1. Pathology indicates small cell carcinoma containing non-small cell carcinoma components; 2. Patients who have previously received systemic treatment; 3. Previous treatment with ADC drugs where the small molecule toxin is a topoisomerase I inhibitor; 4. Use of immunomodulatory drugs within 14 days prior to the first dose of the study drug; 5. History of severe heart disease or cerebrovascular disease; 6. Receiving long-term systemic corticosteroid therapy at a dose \>10 mg/day of prednisone or equivalent prior to the first dose; 7. Active autoimmune diseases and inflammatory diseases; 8. Unstable thrombotic events requiring therapeutic intervention within 6 months prior to screening; 9. Prolonged QT interval, complete left bundle branch block, etc.; 10. Diagnosis of active malignancy within 3 years prior to study randomization; 11. Hypertension inadequately controlled with two antihypertensive medications; 12. Poorly controlled diabetes mellitus; 13. History of interstitial lung disease (ILD)/pneumonitis requiring steroid therapy, etc.; 14. Concurrent pulmonary disease resulting in clinically severe impairment of respiratory function; 15. Patients with active central nervous system (CNS) metastases; 16. Severe infection within 4 weeks prior to study randomization; 17. Presence of large serous cavity effusions, or serous cavity effusions with symptoms, etc.; 18. Imaging findings indicating tumor invasion or encasement of major blood vessels in the abdomen, chest, neck, or pharynx; 19. Severe, non-healing wound, ulcer, or bone fracture within 4 weeks prior to signing informed consent; 20. Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to signing informed consent; 21. Patients with inflammatory bowel disease, history of extensive bowel resection, history of immune-related enteritis, intestinal obstruction, or chronic diarrhea; 22. History of allergy to recombinant humanized antibodies or any excipient component of BL-B01D1; 23. History of autologous or allogeneic stem cell transplantation; 24. Positive for human immunodeficiency virus antibody, active hepatitis B virus infection, or hepatitis C virus infection; 25. History of severe neurological or psychiatric disorders; 26. Receipt of other unapproved clinical study drugs or treatments within 4 weeks prior to study randomization; 27. Subjects planning to receive or having received live vaccines within 28 days prior to study randomization; 28. Other conditions deemed by the investigator to make the subject unsuitable for participation in this clinical trial due to complications or other circumstances.