CD33 x Top I

1. Dose escalation phase Ia (recruitment of approximately 26 patients, determined according to the progress of the study): 1) Primary purpose: observe the safety and tolerability of BL-M11D1 in patients with relapsed/refractory acute myeloid leukemia, so as to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of BL-M11D1. 2) Secondary purpose: evaluate the pharmacokinetic characteristics of BL-M11D1 in patients with relapsed/refractory acute myeloid leukemia. Evaluate the immunogenicity of BL-M11D1 in patients with relapsed/refractory acute myeloid leukemia. 3) Exploratory purpose: detect the expression of CD33 protein on the surface of tumor cells and explore its correlation with the efficacy index of BL-M11D1. 2. Expanded enrollment phase Ib (the actual number of enrollments will be adjusted according to efficacy and safety): 1) Primary purpose: further observe the safety and tolerability of BL-M11D1 at the recommended dose of phase Ia, and determine the recommended dose (RP2D) for phase II clinical studies. 2) Secondary objectives: To evaluate the preliminary efficacy of BL-M11D1 in patients with relapsed/refractory AML. To further evaluate the pharmacokinetic characteristics of BL-M11D1 in patients with relapsed/refractory AML. To evaluate the immunogenicity of BL-M11D1 in patients with relapsed/refractory AML. 3) Exploratory objectives: Based on the results of Phase Ia, further study the correlation between the selected biomarkers and the preliminary efficacy.