A Study Comparing BL-B01D1 With Physician's Choice of Chemotherapy in Patients With Recurrent or Metastatic Nasopharyngeal Carcinoma

Inclusion Criteria:

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

2. Age ≥18 years and ≤75 years;

3. Expected survival time ≥3 months;

4. Patients with recurrent or metastatic nasopharyngeal carcinoma confirmed byhistology or cytology, who have failed treatment with PD-1/PD-L1 monoclonalantibodies and at least two lines of chemotherapy (including at least oneplatinum-based regimen);

5. Patients with recurrent or metastatic nasopharyngeal carcinoma suitable forreceiving the control group chemotherapy drugs specified in this protocol as thelast-line treatment;

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

7. ECOG performance status score of 0 or 1;

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

9. No severe cardiac dysfunction, with left ventricular ejection fraction ≥50%;

10. Organ function levels must meet the requirements without transfusion, use of anycell growth factors, and/or platelet-raising drugs within 14 days beforerandomization;

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

12. Urine protein ≤2+ or <1000mg/24h;

13. For premenopausal women with childbearing potential, a serum pregnancy test must beperformed within 7 days before starting treatment, and the result must be negative.They must not be breastfeeding. All enrolled patients should take adequate barriercontraception measures throughout the treatment period and for 6 months aftertreatment ends.

Exclusion Criteria:

1. Use of chemotherapy, targeted therapy, biologic therapy, etc., within 4 weeks or 5half-lives before randomization, or palliative radiotherapy and antitumor therapywithin 2 weeks;

2. Patients with recurrent nasopharyngeal carcinoma suitable for curative-intent localtreatment (surgery or radiotherapy) should be excluded;

3. Prior treatment with ADC drugs containing topoisomerase I inhibitor as thesmall-molecule toxin, or ADC drugs targeting EGFR and/or HER3;

4. History of severe cardiac disease;

5. Unstable thrombotic events requiring therapeutic intervention within 6 months beforescreening (except for catheter-related thrombosis lasting >4 weeks);

6. QT interval prolongation, complete left bundle branch block, third-degreeatrioventricular block, or frequent and uncontrolled arrhythmias;

7. Diagnosis of active malignancy within 3 years before randomization;

8. Poorly controlled hypertension despite two antihypertensive medications, or poorlycontrolled diabetes, or presence of diabetic gangrene;

9. History of ILD requiring steroid treatment, current ILD, or ≥Grade 2 radiationpneumonitis;

10. Concurrent pulmonary disease resulting in clinically significant respiratoryimpairment;

11. Imaging findings indicating tumor invasion or encasement of major thoracic,cervical, or vascular structures (if the investigator deems it does not affectpatient eligibility, discussion with the sponsor's medical team is required);

12. Patients with active central nervous system metastases;

13. History of allergy to recombinant humanized antibodies or any excipient of BL-B01D1;

14. History of autologous or allogeneic stem cell transplantation;

15. Positive for HIV antibody, active HBV infection, or HCV infection;

16. Severe infection within 4 weeks before randomization, or pulmonary infection oractive pulmonary inflammation within 2 weeks before randomization;

17. Pleural effusion, pericardial effusion, or ascites requiring drainage and/orsymptomatic within 4 weeks before randomization;

18. Use of other investigational drugs or therapies within 4 weeks before randomization;

19. History of severe neurological or psychiatric disorders;

20. Presence of severe unhealed wounds, ulcers, or fractures within 4 weeks beforesigning informed consent;

21. Subjects with clinically significant bleeding or obvious bleeding tendency within 4weeks before signing informed consent;

22. History of intestinal obstruction, inflammatory bowel disease, extensive bowelresection, Crohn's disease, ulcerative colitis, or chronic diarrhea;

23. Subjects planning to receive or having received live vaccines within 28 days beforerandomization;

24. Any other condition deemed by the investigator to make the patient unsuitable forparticipation in this clinical trial.