A Study of BL-M11D1 in Patients With Relapsed/Refractory Acute Myeloid Leukemia

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 CD33-positive relapsed/refractoryacute myeloid leukemia (AML);

6. Morphological assessment showing ≥5% blasts in the bone marrow;

7. ECOG performance status score ≤2;

8. Peripheral blood white blood cell count ≤25×10^9/L before the first dose;

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

10. Organ function levels meet the requirements within 7 days before the first dose;

11. For premenopausal women with childbearing potential, a pregnancy test (serum/urine)must be performed within 7 days before starting treatment, and the result must benegative; they must not be breastfeeding. All enrolled patients (regardless ofgender) must use adequate barrier contraception throughout the treatment period andfor 6 months after treatment ends.

Exclusion Criteria:

1. Acute promyelocytic leukemia, acute transformation of chronic myeloid leukemia.

2. Antineoplastic therapy, including chemotherapy, biologic therapy, immunotherapy,definitive radiotherapy, major surgery (investigator-defined), or targeted therapy (including small-molecule tyrosine kinase inhibitors), has been administered within 4 weeks or 5 half-life cycles (whichever is shorter) before the first dose; Orpalliative radiotherapy within 2 weeks before the first dose.

3. History of severe heart disease, such as left ventricular ejection fraction < 50%,history of symptomatic congestive heart failure (CHF) ≥ grade 2 (CTCAE v5.0), NewYork Heart Association (NYHA) ≥ grade 2 heart failure, history of myocardialinfarction, unstable angina, etc.

4. Prolonged QT interval (QTc > 450 msec in men or QTc > 470 msec in women), completeleft bundle branch block, and III degree atrioventricular block.

5. Active autoimmune diseases and inflammatory diseases, such as systemic lupuserythematosus, psoriasis requiring systemic treatment, rheumatoid arthritis,inflammatory intestinal diseases and Hashimoto's thyroiditis, etc., excluding type Idiabetes mellitus, hypothyroidism that can only be controlled by replacementtherapy, and skin diseases without systemic treatment (such as vitiligo andpsoriasis).

6. Other malignancies diagnosed within 5 years before the first dose, except forradical basal cell carcinoma, squamous cell carcinoma, and/or radical resectioncarcinoma in situ.

7. Poorly controlled hypertension (systolic blood pressure &gt; 150 mmHg or diastolicblood pressure &gt; 100 mmHg).

8. Patients with pulmonary disease grade ≥3 defined by CTCAE v5.0, current or previousinterstitial lung disease (ILD).

9. Patients with central nervous system involvement.

10. Patients with a history of allergy to recombinant humanized antibody or human-mousechimeric antibody or to any of the ingredients of BL-M11D1.

11. Prior organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT).

12. Human immunodeficiency virus (HIVAb) positive, active tuberculosis, active hepatitisB virus infection (HBsAg positive; HBcAb positive and HBV-DNA copy number > lowerdetection limit) or active hepatitis C virus infection (HCV antibody positive andHCV-RNA > lower detection limit).

13. Active infection requiring systemic treatment, such as severe pneumonia, bacteremia,sepsis, etc.

14. Presence of pleural, abdominal, pelvic or pericardial effusion with clinicalsymptoms or requiring repeated drainage.

15. Had participated in another clinical trial within 4 weeks before the first dose (calculated from the time of last dose).

16. Pregnant or lactating women.

17. Other conditions for participation in the trial were not considered appropriate bythe investigator.