PRIMARY OBJECTIVE:
I. To compare the 1-year cumulative incidence of severe Graft Versus Host Disease (GVHD)
(from day of HCT) defined as grade III-IV acute GVHD (aGVHD) and/or chronic GVHD (cGVHD)
that requires systemic immunosuppression and to compare the disease free survival (DFS)
(from time of randomization) in children and young adults (AYA) with acute myeloid
leukemia (AML), acute lymphoid leukemia (ALL), mixed phenotype acute leukemia (MPAL), and
myelodysplastic syndrome (MDS) who are randomly assigned to haploHCT or to an 8/8 adult
MUD-HCT.
SECONDARY OBJECTIVES:
I. To compare overall survival (OS) between children and AYA with AML/ALL/MPAL/MDS
randomly assigned to haploHCT and MUD HCT.
II. To compare differences in health-related quality of life (HRQOL) between haploHCT and
MUD HCT from baseline (pre-transplant), at 6 months, 1 year and 2 years post-transplant.
EXPLORATORY OBJECTIVES:
I. To compare the median time to engraftment and cumulative incidences of neutrophil
engraftment at 30 and 100 days post transplant and platelet engraftment at 60 and 100
days post transplant, primary graft failure by 60 days, secondary graft failure at 1 year
post transplant, Grade II-IV and III-IV acute graft versus host disease (aGVHD) requiring
systemic immunosuppression at 100 days and 6 months, and cumulative incidences of
transplant-related mortality (TRM), relapse, and moderate and severe chronic graft versus
host disease (cGVHD) at 6 months, 1 and 2 years after haploHCT and MUD HCT.
II. To estimate 1 year, 18-month and 2-year cumulative incidence of graft-versus-host
disease (GVHD)-free relapse-free survival (GRFS) with events defined as occurrence of any
of the following from Day 0 of HCT: Grade III-IV acute GVHD, chronic GVHD requiring
systemic immunosuppressive treatment, disease relapse or progression, and death from any
cause.
IIa. To compare "chronic GVHD" (GRFS) after haploHCT and MUD HCT using landmark
definitions.
IIb. To compare "current" GRFS is defined as the time to onset of any of the following
events from Day 0 of HCT: Grade III-IV acute GVHD, chronic GVHD that is STILL requiring
systemic immunosuppressive treatment, disease relapse or progression, death from any
cause at 18 months and 2 years.
III. To evaluate the influence of key clinical variables: age (<13 years and 13-21.99
years), disease (ALL/MPAL versus [vs.] AML/MDS), haploHCT approach (TCR alpha beta + T
cell depletion vs. post-transplant cyclophosphamide [PTCy]); donor age (by ten-year
increments), donor sex (maternal vs. paternal for parental donation), pre-HCT minimal
residual disease status (MRD + vs MRD -); pediatric disease risk index (low,
intermediate, and high, impact on OS and DFS only), conditioning regimen (chemotherapy
based versus total-body irradiation [TBI] based), immunosuppressive regimen
(anti-thymocyte globulin [ATG] exposure according to the weight and absolute lymphocyte
count [ALC] dependent dosing approach vs no ATG exposure) time to transplant (interval
between diagnosis/relapse and date of stem cell infusion) graft cell dose, use of relapse
prevention therapy (yes or no) and weight on engraftment, OS, DFS, GRFS, relapse,
transplant related mortality (TRM), aGvHD and cGvHD at 1 and 2 years after haplo and MUD
HCT by performing stratified and multivariate analyses.
IV. To compare other important transplant related outcomes after haplo and MUD HCT, such
as:
IVa. Incidence of any significant fungal infections (defined as proven or probable fungal
infection) through 1 year post HCT; IVb. Incidence of viremia with or without end organ
disease (i.e. cytomegalovirus [CMV], adenovirus, Epstein-Barr virus [EBV], human
herpesvirus 6 [HHV-6], BK) requiring hospitalization and/or systemic antiviral therapy
and/or cell therapy through 1 year post HCT; IVc. Incidence of sinusoidal obstruction
syndrome (SOS) through 100 days post HCT; IVd. As defined by the Cairo criteria; IVe. To
compare the incidence and outcome of SOS when different criteria are used (European Bone
Marrow Transplant [EBMT], Cairo, Baltimore, and modified Seattle criteria); IVf.
Incidence of transplant-associated thrombotic microangiopathy (TA-TMA) through 100 days
post HCT.
V. To compare immune recovery after haplo PTCy, haplo alpha-beta T cell depletion, and
MUD HCT via:
Va. Pace of reconstitution of T, B, and natural killer (NK) cells and immunoglobulins at
30 days, 60 days, 100 days, 180 days and 365 days after HCT; Vb. Response to vaccinations
as determined by vaccination-specific antibody titers at 12-18 months post hematopoietic
stem cell transplant (HSCT); Vc. Biobanking blood or marrow to analyze the impact of
graft composition on GvHD, relapse and viremia; Vd. Biobanking whole blood and serum to
compare immune recovery using extended immune phenotyping and immune functional
assessments.
VI. Biobanking whole blood or serum to measure rabbit antithymocyte globulin (rATG)
exposure when dosed according to weight and absolute lymphocyte count (ALC) using
established pharmacokinetic and pharmacodynamics assays (after last infusion, Day -4, Day
0, Day +7).
VII. To compare resource utilization after haplo and MUD HCT. VIIa. Length of HCT
hospital stay from Day 0 and readmissions within the first 100 days (number of
readmissions, duration, and reason).
VIIb. Inpatient costs within the first 100 days and at 2 years post HCT. VIII. To
describe and compare outcomes (neutrophil and platelet engraftment, graft failure, OS,
DFS, GRFS, NRM, relapse, GvHD and health-related quality of life [HRQOL] post HCT) by
recipient race/ethnicity, annual household income, primary spoken language and conserved
transcriptional response to adversity (CTRA).
IX. To describe HRQoL outcomes in racial/ethnic minorities and compare HRQoL outcomes
between White patients receiving haploHCT and racial/ethnic minority patients receiving
haploHCT.
X. To assess the feasibility of incorporating total body irradiation (TBI) delivered with
volumetric modulated arc therapy (VMAT) or tomotherapy into a multi-institutional study,
to describe the toxicities and oncologic outcomes (relapse, DFS, OS, and TRM) of the
subgroup of patients treated with this approach, and to compare these outcomes to those
of patients treated with conventional TBI.
OUTLINE: Patients who have both a MUD and haplo donor are randomized to Arm A or Arm B.
Patients who only have a haplo donor are nonrandomly assigned to Arm C.
ARM A: Patients receive a haplo HCT following a TBI- based or chemotherapy-based
myeloablative conditioning regimen with PTCy or alpha beta T cell depletion (center's
choice). When PTCy is used, it Is administered on days 3 and 4 after HCT and additional
immunsouppression is started on day 5 after SCT.
ARM B: Patients receive a MUD HCT following a TBI-based or chemotherapy-based
myeloablative conditioning regimen between days -9 and -2 Patients then receive GVHD
prophylaxis on days 1-11.
ARM C: Patients receive a haploHCT following a TBI-based or chemotherapy-based
myeloablative conditioning regimen with PTCy or alpha beta T cell depletion (center's
choice). When PTCy is used, it Is administered on days 3 and 4 after HCT and additional
immunsouppression is started on day 5 after SCT.
Patients in all arms undergo standard HCT screening prior to transplant including disease
evaluation (lumbar puncture, bone marrow aspiration), and organ function evaluation
including but not limited to echocardiogram (ECHO) or multigated acquisition scan (MUGA),
PFTS, and bloodwork.Patients also undergo collection of blood throughout the trial.
After completion of study treatment, patients are followed periodically for up to 5 years
from HCT.