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

Inclusion Criteria:

1. Sign the informed consent voluntarily and follow the program requirements;

2. No gender limitation;

3. Age: ≥18 years old and ≤75 years old (Stage Ia); ≥18 years old (Ib);

4. Expected survival time ≥3 months;

5. Failure or intolerance to standard treatment confirmed by histopathology and/orcytology or no standard treatment currently available or unresectable locallyadvanced or metastatic breast cancer and other solid tumors for which standardtreatment is not available;

6. Agree to provide archived tumor tissue samples or fresh tissue samples ofprimary or metastatic tumor within 3 years; If subjects are unable to providetumor tissue samples, they will be admitted after evaluation by theinvestigator if other admission criteria are met.

7. Must have at least one measurable lesion as defined by RECIST V1.1;

8. ECOG score of 0 or 1;

9. Toxicity from previous antitumor therapy has returned to level ≤1 as defined byNCI-CTCAE V5.0

10. No serious cardiac dysfunction, left ventricular ejection fraction ≥50%;

11. Organ function level must meet the following requirements and meet thefollowing standards: A) Bone marrow function: absolute neutrophil count (ANC) ≥1.5×10^9/L, platelet count ≥100×10^9/L, hemoglobin ≥90 g/L; B) Liver function:total bilirubin (TBIL≤1.5 ULN), AST and ALT ≤2.5ULN in patients without livermetastasis, AST and ALT ≤5.0 ULN in patients with liver metastasis; C) Renalfunction: Creatinine (Cr) ≤1.5 ULN, or creatinine clearance (Ccr) ≥50 mL/min.

12. Coagulation function: International standardized ratio (INR) ≤1.5, andactivated partial thrombin time (APTT) ≤1.5ULN;

13. Urinary protein ≤2+ or ≤1000mg/24h;

14. For premenopausal women who are likely to have children, a pregnancy test mustbe performed within 7 days of the start of treatment. Serum or urine pregnancymust be negative and must be non-lactation; All enrolled patients (male andfemale) should use adequate barrier contraception throughout the treatmentcycle and 6 months after the end of treatment.

Exclusion Criteria:

1. Prior treatment with ADC drugs using camptothecin derivatives (topoisomerase Iinhibitors) as toxins;

2. Use of chemotherapy, biotherapy, immunotherapy, radical radiotherapy, majorsurgery (as defined by the investigator), targeted therapy (including smallmolecule tyrosine kinase inhibitors) and other antitumor therapies within 4weeks or 5 half-lives, whichever is less, prior to initial dosing; Mitomycinand nitrosourea were administered within 6 weeks prior to initialadministration; Fluorouracil oral agents such as ticio, capecitabine, oralendocrine therapy, or palliative radiotherapy within 2 weeks before initialadministration;

3. History of severe heart disease, such as symptomatic congestive heart failure (CHF) ≥2 (CTCAE 5.0), Heart failure (NYHA) ≥2, history of transmural myocardialinfarction, unstable angina, etc

4. QT prolongation (male QTc > 450 msec or female QTc > 470 msec), complete leftbundle branch block, III atrioventricular block;

5. Active autoimmune and inflammatory diseases, such as systemic lupuserythematosus, psoriasis requiring systemic treatment, rheumatoid arthritis,inflammatory bowel disease and Hashimoto's thyroiditis, are excluded from typeI sugars urinary diseases, hypothyroidism that can be controlled only byalternative therapy, skin diseases that do not require systemic treatment (e.g., vitiligo, psoriasis);

6. Other malignant tumors were diagnosed within 2 years prior to firstadministration, except for radical basal cell carcinoma of the skin, squamouscell carcinoma of the skin, and/or radical resected carcinoma in situ;

7. Hypertension poorly controlled by two antihypertensive medications (systolicblood pressure & GT; 150 mmHg or diastolic pressure & GT; 100 mmHg);

8. Lung disease defined as grade ≥2 according to CTCAE V5.0, and now definedaccording to RTOG/EORTC Grade ≥1 radiation pneumonia; Existing patients withinterstitial lung disease (ILD);

9. Screening for unstable thrombotic events such as deep vein thrombosis, arterialthrombosis and pulmonary embolism requiring therapeutic intervention within thefirst 6 months; Infusion device-related thrombosis is excluded;

10. Primary central nervous system (CNS) malignancy; Patients with CNS metastasiswho have failed local treatment (excluding asymptomatic BMS, or those withstable clinical symptoms and no steroid or other treatment for BMS for ≥28days);

11. Patients with uncontrolled pleural and abdominal effusion with clinicalsymptoms, judged by the investigator to be unsuitable for inclusion;

12. Patients with a history of allergy to recombinant humanized antibody orhuman-mouse chimeric antibody or to any excipient component of BL-B01D1;

13. Prior organ transplantation or allogeneic hematopoietic stem celltransplantation (ALLO-HSCT);

14. Cumulative dose of anthracyclines > 360 mg/m^2 in previous anthracyclines (new)adjuvant therapy

15. Positive human immunodeficiency virus antibody (HIVAb), active tuberculosis,active hepatitis B virus infection (HBV-DNA copy number > 10^3IU/ml) or activehepatitis C virus infection (HCV antibody positive and HCV-RNA > lower limit ofdetection);

16. Active infections requiring systemic treatment, such as severe pneumonia,bacteremia, sepsis, etc.

17. Participated in another clinical trial within 4 weeks prior to initialadministration (starting from the time of last administration);

18. Other conditions considered inappropriate for participation in this clinicaltrial by the investigator