A Study of BL-B01D1 in Patients With Unresectable Locally Advanced or Metastatic Breast Cancer and Other Solid Tumors

Inclusion Criteria:

1. Voluntarily sign the informed consent form and comply with the protocolrequirements;

2. No gender restrictions;

3. Age: ≥18 years and ≤75 years;

4. Expected survival time ≥3 months;

5. Histologically and/or cytologically confirmed unresectable locally advanced ormetastatic breast cancer and other solid tumors with failed standard treatment,intolerance to standard treatment, no current standard treatment available, orinability to access standard treatment;

6. Enrolled subjects should not have received prior systemic therapy for unresectablelocally advanced or recurrent/metastatic triple-negative breast cancer;

7. Agree to provide archived tumor tissue specimens or fresh tissue samples fromprimary or metastatic lesions within the past 3 years;

8. Must have at least one measurable lesion as defined by RECIST v1.1;

9. ECOG performance status score of 0 or 1;

10. Toxicity from prior anti-tumor therapy has recovered to ≤ Grade 1 as defined byNCI-CTCAE v5.0;

11. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥50%;

12. Organ function levels must meet the requirements without transfusion or use of anycell growth factors and/or platelet-raising drugs within 14 days before the firstdose of the study drug;

13. Coagulation function: International Normalized Ratio (INR) ≤1.5, and activatedpartial thromboplastin time (APTT) ≤1.5 × ULN;

14. Urine protein ≤2+ or ≤1000 mg/24h;

15. For premenopausal women with childbearing potential, a pregnancy test (serum orurine) must be performed within 7 days before starting treatment, and the resultmust be negative; they must not be breastfeeding. All enrolled patients (regardlessof gender) must use adequate barrier contraception throughout the treatment periodand for 6 months after treatment ends.

Exclusion Criteria:

1. Received biological therapy, immunotherapy, or other antitumor treatments within 4weeks or 5 half-lives prior to the first dose (6 weeks for mitomycin andnitrosoureas; oral fluorouracil drugs such as tegafur/gimeracil/oteracil (S-1) orcapecitabine, or oral endocrine therapy, or palliative radiotherapy within 2 weeksbefore the first dose);

2. History of severe heart disease;

3. Prolonged QT interval, complete left bundle branch block, third-degreeatrioventricular block, or severe arrhythmia;

4. Active autoimmune or inflammatory diseases;

5. Diagnosis of other malignancies within 2 years prior to the first dose;

6. Poorly controlled hypertension (systolic blood pressure >150 mmHg or diastolic bloodpressure >100 mmHg) despite the use of two antihypertensive medications;

7. Poorly controlled blood glucose (defined as: a) two fasting blood glucose levels >10mmol/L, or b) glycated hemoglobin level exceeding 8%), or concurrent diabeticgangrene;

8. History of interstitial lung disease (ILD), current ILD, or suspected ILD based onimaging during screening;

9. Concurrent pulmonary disease leading to clinically significant respiratoryimpairment;

10. Unstable deep vein thrombosis, arterial thrombosis, pulmonary embolism, or otherthrombotic events requiring therapeutic intervention within 6 months beforescreening (excluding catheter-related thrombosis);

11. Patients with central nervous system (CNS) metastases and/or carcinomatousmeningitis (leptomeningeal metastases);

12. Patients with significant serous cavity effusion, symptomatic effusion, or poorlycontrolled effusion;

13. History of hypersensitivity to recombinant humanized antibodies or human-mousechimeric antibodies, or any excipients of BL-B01D1;

14. Imaging findings indicating tumor invasion or encasement of major thoracic,cervical, or pharyngeal blood vessels, unless the investigator deems it does notaffect the patient's eligibility for treatment;

15. Previous organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT);

16. Cumulative anthracycline dose >360 mg/m² in prior (neo)adjuvant anthracyclinetherapy;

17. Positive for human immunodeficiency virus antibody (HIVAb), active tuberculosis,active hepatitis B virus (HBV) infection, or active hepatitis C virus (HCV)infection;

18. Severe infection (CTCAE > Grade 2) within 4 weeks before the first dose of the studydrug; signs of active pulmonary infection within 2 weeks before the first dose;

19. Participation in another clinical trial within 4 weeks before the first dose (calculated from the last dose date);

20. Any other condition deemed unsuitable for participation in this clinical trial bythe investigator.