A Study of BL-M11D1 in Patients With Relapsed/Refractory Myelodysplastic Syndromes

The study consists of two phases: a dose-exploration phase (Phase Ib) and a dose-expansion phase (Phase II).

Inclusion criteria

• Voluntarily sign the informed consent form and comply with the protocol requirements;
• No gender restrictions;
• Age: ≥18 years and ≤75 years;
• Expected survival time ≥3 months;
• Relapsed/refractory CD33+ MDS;
• Morphological assessment showing blasts in bone marrow ≥5% and <20%;
• Eastern Cooperative Oncology Group (ECOG) performance status ≤2;
• Toxicities from prior anti-tumor therapy must have recovered to ≤ Grade 1 as defined by NCI-CTCAE v6.0;
• Meet the required organ function levels;
• For premenopausal women of childbearing potential, a pregnancy test (serum/urine) must be negative within 7 days before starting treatment, and they must not be breastfeeding; all enrolled trial participants (regardless of gender) must practice adequate barrier contraception throughout the entire treatment period and for 6 months after treatment completion.

Exclusion criteria

• Use of chemotherapy, biotherapy, immunotherapy, etc., within 4 weeks or 5 half-lives prior to the first dose;
• Presence of uncorrected folate deficiency or vitamin B12 deficiency, etc.;
• History of severe cardiovascular or cerebrovascular disease;
• Thromboembolic events requiring therapeutic intervention within 6 months prior to screening;
• Active autoimmune diseases and inflammatory diseases;
• History of extensive bowel resection or presence of Crohn's disease, ulcerative colitis, chronic diarrhea, or intestinal obstruction;
• Diagnosis of another malignancy within 5 years prior to the first dose;
• Poorly controlled hypertension;
• Poorly controlled hyperglycemia or diabetes mellitus;
• Pulmonary diseases classified as Grade ≥3 according to CTCAE v6.0, etc.;
• Trial participants with central nervous system involvement;
• Trial participants with extramedullary involvement;
• Trial participants with a history of allergy to recombinant humanized antibodies or chimeric human-mouse antibodies, or hypersensitivity to any excipient component of BL-M11D1;
• Prior organ transplantation or hematopoietic stem cell transplantation;
• Positive for human immunodeficiency virus antibody, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection;
• Active fungal, bacterial, or viral infections;
• History of severe neurological or psychiatric disorders;
• Trial participants with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to signing informed consent;
• Presence of clinically symptomatic pleural, peritoneal, or pericardial effusion requiring repeated drainage;
• Participation in another clinical trial within 4 weeks or 5 half-lives prior to the first dose;
• Pregnant or breastfeeding women;
• Other conditions deemed by the investigator to make the participant unsuitable for participation in this clinical trial.