A Study of BL-M24D1 in Patients With Relapsed or Refractory Multiple Myeloma and Other Hematologic Malignancies

The study is divided into two phases: a dose escalation phase (Phase Ia) and an expansion cohort phase (Phase Ib).

Inclusion criteria

• Voluntarily sign the informed consent form and comply with the protocol requirements;
• Gender is not restricted;
• Age: ≥18 years and ≤75 years (Phase Ia); ≥18 years (Phase Ib);
• Expected survival time ≥3 months;
• Histologically and/or cytologically confirmed multiple myeloma or other hematologic malignancies that have failed standard treatment or for which no standard treatment currently exists;
• Must have measurable indicators as defined by the protocol;
• Physical condition score ECOG 0 or 1;
• Toxicity from previous antitumor treatments has recovered to ≤ Grade 1 as defined by NCI-CTCAE v5.0;
• No severe cardiac dysfunction, left ventricular ejection fraction ≥50%;
• Organ function levels must meet the requirements;
• Coagulation function: International Normalized Ratio (INR) ≤1.5, and activated partial thromboplastin time (APTT) ≤1.5 × ULN;
• For premenopausal women with childbearing potential, a pregnancy test must be conducted within 7 days before starting treatment, the serum pregnancy test must be negative, and they must not be breastfeeding; all enrolled patients (regardless of gender) should adopt adequate barrier contraception throughout the treatment cycle and for 6 months after the end of treatment.

Exclusion criteria

• Subjects with central nervous system involvement, etc.;
• Use of chemotherapy, biologics, immunotherapy, etc., within 4 weeks prior to the first dose or within 5 half-lives;
• History of severe heart disease;
• QT interval prolongation, complete left bundle branch block, third-degree atrioventricular block;
• Active autoimmune diseases and inflammatory diseases;
• Diagnosis of other malignancies within 5 years prior to the first dose;
• Hypertension poorly controlled by two antihypertensive medications;
• Patients with poorly controlled blood glucose;
• Unstable thrombotic events requiring therapeutic intervention within 6 months prior to the first dose;
• Lung diseases defined as ≥ Grade 3 according to CTCAE v5.0; history of interstitial lung disease requiring hormone treatment, etc.;
• Patients with peripheral neuropathy ≥ Grade 3 or persistent ≥ Grade 2 peripheral neuropathy with pain;
• Patients with a history of allergy to recombinant humanized antibodies or human-mouse chimeric antibodies, or allergy to any excipient component of BL-M24D1;
• Previous organ transplantation or allogeneic hematopoietic stem cell transplantation (Allo-HSCT);
• Human immunodeficiency virus antibody positivity, active tuberculosis, active hepatitis B virus infection, or active hepatitis C virus infection;
• Active infection requiring systemic treatment within 4 weeks prior to the first study drug administration, etc.;
• Pleural, abdominal, pelvic, or pericardial effusion requiring drainage and/or accompanied by symptoms within 4 weeks prior to the first study drug administration;
• Subjects with clinically significant bleeding or obvious bleeding tendency within 4 weeks prior to the first study drug administration;
• Participation in another clinical trial within 4 weeks prior to the first dose;
• Pregnant or breastfeeding women;
• Patients who received live vaccines within 30 days prior to the first dose;
• Other conditions deemed by the investigator as unsuitable for participation in this clinical trial.