A Study of BL-M07D1 in Patients With a Variety of Solid Tumors Including Locally Advanced or Metastatic HER2-positive/Low-expressing Urinary and Gastrointestinal Tumors

Inclusion Criteria: 1. Voluntarily sign the informed consent form and comply with the protocol requirements; 2. No gender restrictions; 3. Age: ≥18 years and ≤75 years; 4. Expected survival time ≥3 months; 5. Patients with unresectable locally advanced or metastatic HER2-positive/low-expressing urological and digestive system tumors, as well as other solid tumors; 6. Agree to provide archived tumor tissue specimens or fresh tissue samples from primary or metastatic lesions within the past 2 years; 7. Must have at least one measurable lesion as defined by RECIST v1.1; 8. ECOG performance status score of 0 or 1; 9. Toxicity from prior anti-tumor therapy has recovered to ≤ Grade 1 as defined by NCI-CTCAE v5.0; 10. No severe cardiac dysfunction, with left ventricular ejection fraction (LVEF) ≥50%; 11. Organ function levels must meet the requirements; 12. Coagulation function: International Normalized Ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5 × ULN; 13. Urine protein ≤2+ or ≤1000 mg/24h; 14. Albumin ≥30 g/L; 15. For premenopausal women with childbearing potential, a pregnancy test (serum/urine) must be performed within 7 days before starting treatment, and the result must be negative; they must not be breastfeeding. All enrolled patients (regardless of gender) must use adequate barrier contraception throughout the treatment period and for 7 months after treatment ends. Exclusion Criteria: 1. Received chemotherapy, biological therapy, immunotherapy, or other antitumor treatments within 4 weeks or 5 half-lives prior to the first dose; 2. Previously treated with ADC drugs containing camptothecin derivatives as payloads; 3. History of severe cardiovascular or cerebrovascular diseases; 4. Active autoimmune or inflammatory diseases; 5. History of other malignancies within 5 years prior to the first dose; 6. Thrombotic events requiring therapeutic intervention within 6 months before screening; 7. Patients with significant pleural/peritoneal/pelvic effusion or pericardial effusion, or those with symptomatic effusion, or poorly controlled effusion; 8. Poorly controlled hypertension despite antihypertensive medication; 9. Current interstitial lung disease, drug-induced interstitial pneumonitis, radiation pneumonitis requiring steroid treatment, or history of these conditions; 10. Patients with primary central nervous system (CNS) tumors or CNS metastases that failed local treatment; 11. History of hypersensitivity to recombinant humanized antibodies or human-mouse chimeric antibodies, or any excipients of BL-M07D1; 12. Previous organ transplantation or allogeneic hematopoietic stem cell transplantation; 13. Positive for human immunodeficiency virus (HIV) antibodies, active tuberculosis, or active hepatitis C virus (HCV) infection; 14. Active hepatitis B virus (HBV) infection (exclusion criterion); 15. Severe infection requiring systemic treatment within 4 weeks before the first dose of the study drug; 16. Participation in another clinical trial within 4 weeks before the first dose; 17. Pregnant or lactating women; 18. Any other condition deemed unsuitable for participation in this clinical trial by the investigator.