A Phase 1 Study of Orca-Q in Recipients Undergoing Allogeneic Transplantation for Hematologic Malignancies

Open to people ages 12-78

1. Age ≥ 12 and ≤ 78 years at the time of enrollment
2. Diagnosed acute myeloid, lymphoid or mixed phenotype leukemia, or high or very high risk myelodysplasic syndrome (MDS) either in complete remission (CR) or with ≤ 10 percent of blast cells in bone marrow (BM)
3. Planned to undergo allogeneic hematopoietic stem cell transplant (alloHCT)
4. Matched to a 8/8 or 7/8 related or unrelated donor, or to a related haploidentical donor
5. Estimated glomerular filtration rate (eGFR) > 50 mL/minute (MAC with tacrolimus) or > 30 mL/minute (NMA/RIC or MAC without tacrolimus)
6. Cardiac parameters: Cardiac ejection fraction ≥ 45 percent (MAC) or ≥ 40 percent (NMA/RIC)
7. Diffusing capacity of the lung for carbon monoxide (DLCO) (adjusted for hemoglobin) ≥ 50 percent for MAC or ≥ 40 percent for NMA/RIC
8. Liver function: Total bilirubin < 1.5 times upper limit of normal (ULN) (MAC) or < 3 times ULN (NMA/RIC); alanine transaminase (ALT)/aspartate transaminase (AST) < 3 times ULN (MAC) or < 5 times ULN (NMA/RIC)
9. Participants enrolling on NMA/RIC-alloHCT arms must be deemed unfit for a myeloablative alloHCT per assessment of the principal investigator (PI)

1. Prior alloHCT
2. Currently receiving corticosteroids or other immunosuppressive therapy. Topical corticosteroids or oral systemic corticosteroid doses less than or equal to 10 mg/day are allowed.
3. Planned donor lymphocyte infusion (DLI)
4. Planned pharmaceutical in vivo or ex vivo T cell depletion, e.g., post-transplant cyclophosphamide (Cy) or alemtuzumab
5. Positive anti-donor HLA antibodies against a mismatched allele in the selected donor

6. Low performance score: For MAC: Karnofsky Performance Score (KPS) < 70 percent, For

   NMA/RIC: <60 percent

7. High HCT-specific Comorbidity Index (HCT-CI): For MAC > 4, For NMA/RIC >6
8. Uncontrolled bacterial, viral or fungal infections (currently taking antimicrobial therapy and with progression or no clinical improvement) at time of enrollment
9. Seropositive for human immunodeficiency virus (HIV)-1 or -2, human T-lymphotropic virus (HTLV)-1 or -2 or Hepatitis B surface antigen (HbsAg) or anti-Hepatitis C virus (HCV) antibody (Ab)
10. Any uncontrolled autoimmune disease requiring active immunosuppressive treatment
11. Concurrent malignancies or active disease within 1 year, except non-melanoma skin cancers that have been curatively resected
12. History of idiopathic or secondary myelofibrosis
13. Women who are pregnant or breastfeeding