Inclusion Criteria:
1. Voluntarily sign the informed consent form and agree to comply with the protocol requirements;
2. No gender restriction;
3. Age: ≥ 18 years and ≤ 75 years;
4. Expected survival time ≥ 3 months;
5. Locally advanced or metastatic urological tumors and other solid tumors;
6. Agree to provide archived tumor tissue specimens collected within 2 years from the primary or metastatic lesion, or fresh tissue samples;
7. Must have at least one measurable lesion as defined by RECIST v1.1;
8. Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1;
9. Toxicities from prior anti-tumor therapy must have recovered to ≤ Grade 1 as defined by NCI-CTCAE v6.0;
10. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥ 50%;
11. Organ function levels must meet the specified requirements;
12. Coagulation function: International Normalized Ratio (INR) ≤ 1.5, and activated partial thromboplastin time (aPTT) ≤ 1.5 × upper limit of normal (ULN);
13. Urine protein ≤ 1+ or ≤ 1000 mg/24h;
14. For premenopausal women of childbearing potential, a serum pregnancy test must be performed within 7 days prior to the start of treatment, with a negative result, and they 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 completion of treatment;
15. The trial participant must be willing and able to comply with the visit schedule, treatment plan, laboratory tests, and other study-related procedures as specified in the protocol.
Exclusion Criteria:
1. Use of chemotherapy, biotherapy, immunotherapy, or similar treatments within 4 weeks or 5 half-lives prior to the first dose;
2. Receipt of immunosuppressive therapy within 2 weeks prior to the first dose;
3. History of severe cardiac or cerebrovascular disease;
4. Prolonged QTc interval, complete left bundle branch block, third-degree atrioventricular block, or frequent and uncontrolled arrhythmias;
5. Active autoimmune diseases and inflammatory diseases;
6. Prior history of ≥ Grade 3 toxicity related to anti-angiogenic therapy when receiving such treatment previously;
7. Diagnosis of another solid tumor within 5 years prior to the first dose;
8. Unstable thrombotic events requiring therapeutic intervention within 6 months prior to the first dose;
9. Uncontrolled hypertension;
10. Diabetes mellitus with poor glycemic control;
11. History of interstitial lung disease (ILD) requiring corticosteroid therapy, or current ILD, or ≥ Grade 2 radiation pneumonitis;
12. Concurrent pulmonary disease resulting in severe impairment of respiratory function;
13. Active central nervous system (CNS) metastases;
14. History of hypersensitivity to recombinant humanized antibodies or human-mouse chimeric antibodies, or allergy to any excipient of SI-B036;
15. Prior history of organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT);
16. Positive for human immunodeficiency virus (HIV) antibodies, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection;
17. Active infection requiring systemic therapy within 4 weeks prior to the first dose of the study drug;
18. Presence of pleural, abdominal, or pelvic effusion, or pericardial effusion requiring drainage and/or associated with symptoms within 4 weeks prior to the first dose of the study drug;
19. Imaging findings indicating that the tumor has invaded or encased the great thoracic vessels, pericardium, or heart;
20. Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to screening;
21. History of fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to the first dose;
22. Use of another investigational drug within 4 weeks or 5 half-lives prior to the first dose;
23. Pregnant or lactating women;
24. Other conditions that, in the investigator's opinion, make the subject unsuitable for participation in this clinical trial.
