Double Cord Versus Haploidentical (BMT CTN 1101)

Summary

Objectives

Reduced intensity conditioning (RIC) blood or marrow transplantation (BMT) has allowed older
and less clinically fit patients to receive potentially curative treatment with allogeneic
HCT for high risk or advanced hematological malignancies. Patients lacking an HLA-matched
sibling may receive a graft from a suitably HLA-matched unrelated donor. However, up to a
third of patients will not have an HLA-matched sibling or a suitably matched adult unrelated
donor (i.e., no more than a mismatch at a single locus). Even when a suitably matched
unrelated donor is identified, data from the National Marrow Donor Program (NMDP) indicate
that a median of four months is required to complete searches that result in transplantation;
thus, some number of patients succumb to their disease while awaiting identification and
evaluation of a suitably matched adult unrelated donor.

Single or dual center studies have shown that partially HLA-mismatched related bone marrow
(haplo-BM) and unrelated double umbilical cord blood (dUCB) are valuable sources of donor
cells for RIC HCT, thus extending this treatment modality to patients who lack other donors.
In order to study the reproducibility, and thus, the wider applicability of these two
alternative donor strategies, The Blood and Marrow Transplantation Clinical Trials Network
(BMT CTN) conducted two parallel multicenter prospective Phase II clinical trials. These two
studies evaluated the safety and efficacy of related haplo-BM (BMT CTN 0603) and dUCB (BMT
CTN 0604) transplantation after RIC. Both of these alternative donor approaches produced
early results similar to that reported with unrelated donor, and even HLA-matched sibling,
HCT. These data demonstrate not only the efficacy of both of these approaches, but also that
both can be safely exported from the single center setting. Both haplo-BM and dUCB grafts can
be obtained rapidly for greater than 90% of patients lacking an HLA-matched donor. This study
will test the hypothesis that progression free survival at two years after RIC haplo-BM
transplantation is similar to the progression free survival after RIC dUCB transplantation.