A Study of BL-B01D1 + PD-1 in Patients With Locally Advanced or Metastatic Urothelial Carcinoma

Inclusion Criteria: 1. All subjects voluntarily participated in the study and signed informed consent; 2. Male or female aged ≥18 years and ≤75 years; 3. Expected survival time ≥3 months; 4. ECOG 0-1; 5. Unresectable locally advanced or metastatic urothelial carcinoma confirmed by histopathology and/or cytology; 6. Participants should not have received previous systemic therapy for locally advanced or metastatic urothelial cancer; 7. A biopsy sample of archived tumor tissue or metastatic urothelial carcinoma must be available within 3 years for PD-L1 and other testing; 8. At least one measurable lesion meeting the RECIST v1.1 definition was required; 9. The level of organ function must meet the requirements on the premise that blood transfusion and the use of any cell growth factors and/or platelet-raising drugs are not allowed within 14 days before the first dose; 10. Previous treatment-related toxicity returned to ≤ grade 1 defined by NCI-CTCAE v5.0; 11. For premenopausal women with childbearing potential, a pregnancy test must be performed within 7 days before the initiation of treatment, the serum or urine pregnancy test must be negative, and the patient must not be lactating; All enrolled patients should take adequate barrier contraception during the entire treatment cycle and for 6 months after the end of treatment. Exclusion Criteria: 1. Prior ADC recipients with TOPI inhibitors as toxin; 2. Palliative radiotherapy within 2 weeks before the first dose; 3. Prior immunotherapy with grade ≥3 irAE or grade ≥2 immune-related myocarditis; 4. Use of an immunomodulatory drug within 14 days before the first dose of study drug; 5. The history of severe cardiovascular and cerebrovascular diseases in the past six months was screened; 6. QT prolongation, complete left bundle branch block, III degree atrioventricular block, frequent and uncontrollable arrhythmia; 7. Active autoimmune and inflammatory diseases; 8. Receiving \&gt before the first dose; Long-term systemic corticosteroid therapy with prednisone 10mg/d; 9. Other malignant tumors that progressed or required treatment within 5 years before the first dose; 10. Presence of: a) poorly controlled diabetes mellitus before starting study treatment; b) severe complications associated with diabetes mellitus; c) a glycated hemoglobin level of 8% or more; d) hypertension poorly controlled by two antihypertensive drugs; e) history of hypertensive crisis or hypertensive encephalopathy; 11. History of ILD, current ILD, or suspected ILD; 12. Complicated with pulmonary diseases leading to clinically severe respiratory impairment; 13. Screening for unstable thrombotic events requiring therapeutic intervention within the preceding 6 months; Infusion-related thrombosis was excluded; 14. Patients with active central nervous system metastases; 15. Patients with massive or symptomatic effusions or poorly controlled effusions; 16. Patients with a history of allergy to recombinant humanized antibody or human-mouse chimeric antibody or allergic to any excipients of the test drug; 17. Prior organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT); 18. HIV antibody positive, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection; 19. Serious infection within 4 weeks before the first dose of study drug; Signs of pulmonary infection or active pulmonary inflammation within 4 weeks; 20. Participated in another clinical trial within 4 weeks before the first dose; 21. Patients with superior vena cava syndrome should not be rehydrated; 22. Have a history of psychotropic substance abuse with an inability to quit or a history of severe neurological or psychiatric illness; 23. Imaging examination showed that the tumor had invaded or wrapped the large thoracic vessels; 24. Severe unhealed wound, ulcer, or fracture within 4 weeks before signing the informed consent; 25. Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks before signing the informed consent; 26. Subjects who are scheduled to receive live vaccine or receive live vaccine within 28 days before the first dose; 27. Other circumstances considered by the investigator to be inappropriate for participation in the trial.