Calcineurin Inhibitor-Free Interventions for Prevention of Graft-versus-Host Disease (BMT CTN 1301)

Chronic Graft-versus-Host Disease (GVHD) is a complication that affects many hematopoietic
stem cell transplant (HSCT) survivors; it occurs when the new cells from a transplant attack
the recipient's body. The current standard GVHD prophylaxis regimen for patients with
hematologic malignancies undergoing HSCT involves a combination of immunosuppressive agents
given for the first 6 months after transplant. Often, patients develop GVHD and continue on
these agents for much longer periods. The combination of calcineurin inhibitors (tacrolimus
and cyclosporine A) with methotrexate (MTX) is the most common GVHD prophylaxis used
worldwide in the context of myeloablative conditioning transplants. This regimen demonstrates
better control of acute GVHD, but is less effective against chronic GVHD. Management of
chronic GVHD remains a challenge and it has become a significant health problem in transplant
survivors with more frequent use of mobilized peripheral blood stem cells. Additionally,
several issues arise with the standard approach including various toxicity symptoms and side
effects, increased risk of thrombotic microangiopathy due to CNI, no prevention of other
infectious diseases, and no prevention for disease relapse.

This standard strategy of Tac/MTX will be used as a control in comparison to two other
treatment plans both utilizing CNI-free methods: CD34 selected T-cell depletion in peripheral
blood stem cell (PBSC) grafts, and infusion of bone marrow (BM) grafts followed by
post-transplant Cyclophosphamide (PTCy). Study participants will be randomized to one of
these three treatment arms.

Inclusion Criteria:

1. Males and females aged ≥ 1.0 year and < 66.0 years

2. Patients with acute leukemia in morphologic complete remission with or without
hematologic recovery or with myelodysplasia (MDS) with no circulating blasts and with
less than 5% blasts in the bone marrow. Patients with CMML must have a WBC count ≤
10,000 cells/µL and < 5% blasts in the marrow. Patients with ≥ 5% blasts due to a
regenerating marrow must contact the protocol chairs for review.

3. Planned myeloablative conditioning regimen

4. Patients must have a related or unrelated donor as follows:

1. Related donor must be an 8/8 match for human leukocyte antigen (HLA)-A, -B, and
-C at intermediate (or higher) resolution, and -DRB1 at high resolution using
DNA-based typing. Pediatric related donors must weigh ≥ 25.0 kg., must have
adequate peripheral venous catheter access for leukapheresis or must agree to
placement of a central catheter, must be willing to (1) donate bone marrow and
(2) receive G-CSF followed by donation of peripheral blood stem cells (product to
be determined by randomization post enrollment) and must meet institutional
criteria for donation.

2. Unrelated donor must be an 8/8 match at HLA-A, -B, -C and -DRB1 at high
resolution using DNA-based typing. Unrelated donor must be medically eligible to
donate according to National Marrow Donor Program (NMDP) (or equivalent donor
search organization) criteria. At time of enrollment, the donor should not have
any known preferences or contraindications to donate bone marrow or peripheral
blood stem cells. (Selection of unrelated donors is to be performed according to
institutional practice. It is recommended that the time from collection to
initiation of the cell processing be considered when prioritizing donors, as data
shows better results for CD34 selection when cell processing begins within 36
hours of the end of collection)

5. Cardiac function: Ejection fraction at rest ≥ 45.0% or shortening fraction of ≥ 27.0%
by echocardiogram or radionuclide scan (MUGA).

6. Estimated creatinine clearance (for patients > 12 years) greater than 50.0 mL/minute
(using the Cockcroft-Gault formula and actual body weight); for pediatric patients (>
1 year to 12 years), Glomerular Filtration Rate (GFR) estimated by the updated
Schwartz formula ≥ 90.0 mL/min/1.73 m^2. If the estimated creatinine clearance is < 90
mL/min/1.73 m^2, then renal function must be measured by 24-hour creatinine clearance
or nuclear GFR, and must be > 70.0 mL/min/1.73 m^2.

7. Pulmonary function: Diffusing capacity of the lung for carbon monoxide (DLCO) ≥ 50%
(adjusted for hemoglobin), and forced expiratory volume in one second (FEV1) or forced
vital capacity (FVC) ≥ 50%; for children who are unable to perform for Pulmonary
Function Tests (PFTs) due to age or developmental ability, there must be no evidence
of dyspnea and no need for supplemental oxygen, as evidenced by O2 saturation ≥ 92% on
room air.

8. Liver function: total bilirubin < 2x the upper limit of normal (unless elevated
bilirubin is attributed to Gilbert's Syndrome) and alanine aminotransferase (ALT) /
aspartate aminotransferase (AST) < 2.5x the upper limit of normal.

9. Signed informed consent.

Exclusion Criteria:

1. Prior autologous or allogeneic hematopoietic stem cell transplant

2. Karnofsky or Lansky Performance Score < 70%

3. Active central nervous system (CNS) involvement by malignant cells

4. Patients with uncontrolled bacterial, viral or fungal infections (currently taking
medication and with progression or no clinical improvement) at time of enrollment

5. Presence of fluid collection (ascites, pleural or pericardial effusion) that
interferes with methotrexate clearance or makes methotrexate use contraindicated

6. Patients seropositive for HIV-1 or -2

7. Patients seropositive for Human T-Lymphotrophic Virus (HTLV)-I or -II

8. Patients with active Hepatitis B or C viral replication by polymerase chain reaction
(PCR)

9. Documented allergy to iron dextran or murine proteins

10. Women who are pregnant (positive serum or urine βHCG) or breastfeeding

11. Females of childbearing potential (FCBP) or men who have sexual contact with FCBP
unwilling to use 2 effective forms of birth control or abstinence for one year after
transplantation

12. History of uncontrolled autoimmune disease or on active treatment

13. Patients with prior malignancies, except resected non-melanoma or treated cervical
carcinoma in situ. Cancer treated with curative intent ≥ 5 years previously will be
allowed. Cancer treated with curative intent < 5 years previously will not be allowed
unless approved by the Protocol Officer or one of the Protocol Chairs.

14. Patient unable to comply with the treatment protocol including appropriate supportive
care, follow-up and research tests

15. Planned post-transplant maintenance therapy except for FLT3 inhibitors or TKIs must be
declared prior to randomization.

16. If it is known prior to enrollment that the hematopoietic stem cell product will need
to be cryopreserved, the patient should not be enrolled.

17. German centers only: Treatment with any known non-marketed drug substance or
experimental therapy within 5 terminal half lives or 4 weeks prior to enrollment,
whichever is longer, or participation in any other interventional clinical study.