A Study of BL-M17D1 in Patients With Locally Advanced or Metastatic HER2 Positive/Negative Breast Cancer and Other Solid Tumors

Inclusion Criteria: 1. Sign the informed consent form voluntarily and follow the protocol requirements; 2. Gender is not limited; 3. Age: ≥18 years old and ≤75 years old (stage Ia); ≥18 years old (stage Ib); 4. Expected survival time ≥3 months; 5. Patients with locally advanced or metastatic HER2-positive/negative breast cancer and other solid tumors; 6. Agree to provide archival tumor tissue samples or fresh tissue samples of primary or metastatic lesions within 3 years; 7. Must have at least one extracranial measurable lesion that meets the RECIST v1.1 definition; 8. ECOG 0 or 1; 9. The toxicity of previous antineoplastic therapy has returned to ≤ grade 1 as defined by NCI-CTCAE v5.0; 10. No severe cardiac dysfunction, left ventricular ejection fraction ≥50%; 11. No blood transfusion is allowed within 14 days before the first use of the study drug, and no cell growth factor is allowed. The organ function level must meet the requirements; 12. Coagulation function: international normalized ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5ULN; 13. For premenopausal women of childbearing potential, a pregnancy test must be performed within 7 days before the initiation of treatment, serum pregnancy must be negative, and the patient must not be lactating; All enrolled patients (male or female) were advised to use adequate barrier contraception throughout the treatment cycle and for 6 months after the end of treatment. Exclusion Criteria: 1. Chemotherapy, biological therapy and other anti-tumor therapies have been used within 4 weeks or 5 half-lives before the first dose; Mitomycin and nitrosoureas were administered within 6 weeks before the first dose; Oral drugs such as fluorouracil; 2. History of severe heart disease; 3. Prolonged QT interval, complete left bundle branch block, III degree atrioventricular block, frequent and uncontrollable arrhythmia; 4. Active autoimmune and inflammatory diseases; 5. Other malignancies diagnosed within 5 years before the first dose; 6. Unstable thrombotic events requiring therapeutic intervention within 6 months before screening; Infusion-related thrombosis was excluded; 7. Hypertension poorly controlled by two antihypertensive drugs (systolic blood pressure \> 150 mmHg or diastolic blood pressure \> 100 mmHg); 8. A history of ILD requiring steroid therapy, or current ILD or radiation pneumonitis of grade ≥1 according to the RTOG/EORTC definition, or a suspicion of such disease; 9. Patients with poor glycemic control; 10. Complicated with pulmonary diseases leading to clinically severe respiratory function impairment; 11. Patients with primary central nervous system tumors or CNS metastases after failure of local treatment; 12. Patients with a history of allergy to recombinant humanized antibody or human-mouse chimeric antibody or to any of BL-M17D1's excipients; 13. Prior organ transplantation or allogeneic hematopoietic stem cell transplantation; 14. Prior anthracycline therapy with more than the protocol-specified cumulative dose of an anthracycline; 15. Human immunodeficiency virus antibody positive, active tuberculosis, active hepatitis B virus infection or active hepatitis C virus infection; 16. Active infection requiring systemic therapy with a serious infection within 4 weeks prior to informed consent; There were indications of pulmonary infection or active pulmonary inflammation within 2 weeks before informed consent; 17. Patients with massive or symptomatic effusions, or poorly controlled effusions; 18. Had participated in another clinical trial within 4 weeks before the first dose; 19. Pregnant or lactating women; 20. Patients with superior vena cava syndrome should not be rehydrated; 21. A history of severe neurological or psychiatric illness; 22. Severe unhealed wounds, ulcers, or fractures within 4 weeks before signing the informed consent; 23. Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks before signing the informed consent; 24. History of intestinal obstruction, inflammatory bowel disease or extensive bowel resection or presence of Crohn's disease, ulcerative colitis or chronic diarrhea; 25. Who are scheduled to receive live vaccine or who receive the vaccine within 28 days before the first dose; 26. The investigators did not consider it appropriate to apply other conditions for participation in the trial.