Precision-T: A Study of Orca-T in Recipients Undergoing Allogeneic Transplantation for Hematologic Malignancies

Key Inclusion Criteria:

Recipients must meet all of the following criteria:

   1. Patients must diagnosed with one of the following histopathologically confirmed
   diseases, for which a myeloablative hematopoietic stem cell transplant (HCT) is
   planned:

   A) Acute myeloid, lymphoid, or mixed phenotype/undifferentiated leukemia who are not
   in CR or CRi (active disease) and/or MDS with >10% to <20% bone marrow blast burden
   (ages 18 to 75 years)

   B) Acute leukemia in CR/CRi or MDS that is DRI intermediate to high risk (ages 66 to
   75 years)

   C) BPDCN (ages 18 to 65 years)

   D) Participants aged 18 to 65 who would be eligible for the Phase 3 component of
   Precision-T except for mild impairments of renal and/or hepatic function as defined by
   an eGFR of 50 to <60 mL/min and/or a total bilirubin of >ULN to ≤2 x ULN and diagnosed
   with either of the following:

   i. Acute myeloid, lymphoid, or mixed phenotype/undifferentiated leukemia that is in
   CR/CRi and DRI intermediate to high risk

   a) MDS that is DRI intermediate to high risk

   E) Acute or chronic leukemia in remission that is DRI low risk (ages 18 to 65 years),
   including the following:

   i. CML in chronic phase but with a history of accelerated phase or blast crisis or who
   are resistant to or intolerant of more than 1 first- and second-generation tyrosine
   kinase inhibitors

   ii. Acute myeloid leukemia (AML) with inv(16) without accompanying complex
   cytogenetics

   2. Patients must be matched to a 8/8 HLA-matched related or unrelated donor

   3. Estimated glomerular filtration rate (eGFR) > 50 mL/minute

   4. Cardiac ejection fraction at rest ≥ 45% or shortening fraction of ≥ 27% by
   echocardiogram or radionuclide scan (MUGA)

   5. Diffusing capacity of the lung for carbon monoxide (DLCO) (adjusted for hemoglobin) ≥
   50%

   6. Total bilirubin < 2 times upper limit of normal (ULN) (patients with Gilbert's
   syndrome may be included where hemolysis has been excluded) and ALT/AST < 3 times ULN

Key Exclusion Criteria:

Recipients meeting any of the following exclusion criteria will not be eligible:

   1. History of prior allogeneic HCT

   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. Pre-planned donor lymphocyte infusion (DLI)

   4. Planned pharmaceutical in vivo or ex vivo T cell depletion

   5. Positive for anti-donor HLA antibodies against an allele in the selected donor

   6. Karnofsky performance score < 70%

   7. Hematopoietic cell transplantation-specific Comorbidity Index (HCT-CI) > 4

   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 HIV-1 or -2 antibody, HTLV-1 or -2 antibody, Hepatitis B sAg, or
   Hepatitis C antibody

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. Women who are pregnant or breastfeeding