BSB-1001 in Patients Undergoing HLA-Matched Allogenic Hematopoietic Stem Cell Transplant for AML, ALL or MDS

Inclusion Criteria

• Male or female patients, ages 18 - 70 years inclusive, undergoing alloHCT.
• Any of the following high-risk hematologic malignancies:
• AML diagnosed which has been treated with at least two lines of therapy* Refractory or relapsed (CR, CRh or CRi,), including myeloblasts up to 25% OR MRD positive OR persistent disease-defining cytogenetic abnormality OR MRD-negative, but with high-risk disease For patients in remission meeting criteria a, consolidation regimens would be considered another line of therapy of eligibility purposes
• ALL which has been with abnormal lymphoblasts ≥5% and up to 25% in bone marrow OR persistent disease-defining cytogenetic abnormality or MRD positive
• MDS after at least one line of therapy, which includes hypomethylating agent(s) and must be high or very high risk by Revised International Prognostic Scoring System (IPSS-R), monosomy, or complex karyotype or TP53 mutation.
• In the expansion phase AML patients diagnosed which has been treated with at least two lines of therapy, and refractory or relapsed (CR, CRh or CRi,), including myeloblasts up to 25% OR MRD positive OR persistent disease-defining cytogenetic abnormality OR MRD-negative, but with high- risk disease
• HLA-A*02:01 AND HA-1 positive (either H/H or H/R).
• Suitable for one of the approved conditioning regimens as defined in the protocol.
• Patient must have an identified donor that is HA 1-negative with 10/10 matched related or unrelated donor

Exclusion Criteria

• Weight > 100 kg.
• Prior history of allogeneic stem cell transplantation
• Prior history of autologous stem cell transplantation within 1 year prior to the planned dosing of BSB-1001 (day 0)
• Previous genetically engineered chimeric antigen receptor T Cell therapy (CAR-T), approved or investigational, within 2 years of screening, with the exception of patients with ALL previously treated with an autologous CAR-T product.
• Treatment with other investigational agents within 5 half-lives of the planned dosing of BSB-1001 (day 0).
• History of treatment with checkpoint inhibitor therapy within 3 months of transplantation.
• Other malignancy with life expectancy < 1year.
• Pregnant or lactating women.
• Uncontrolled bacterial, viral, or fungal infections at time of enrollment.
• Past or current viral infections as defined in the protocol.
• CNS involvement refractory to intrathecal chemotherapy and/or standard cranial- spinal radiation. 12 Karnofsky Performance Score < 60%.
• Inadequate organ function as defined in protocol.