This is a clinical trial for subjects with hematologic malignancies ( acute leukemia,
myeloproliferative disorders, lymphoma, myeloma) who are in need of a donor stem cell
transplant, and for whom an umbilical cord blood transplant is thought to be the best
option. As donors for allogeneic transplant, we typically try to use related family
members, such as brothers or sisters, or volunteer donors who are 'HLA matched', i.e.
share similar proteins on their cells. This study is for subjects for whom such a matched
sibling donor or a matched unrelated donor is not available.
For such subjects a commonly used transplant procedure is to use stem cells from one or
two umbilical cords (UCB) from a newborn. These umbilical cord blood grafts, despite not
completely matching the recipient, cause few problems with graft vs host disease (a
common complication of transplant). But they tend to grow very slowly and subjects often
have very prolonged hospital stays and are at high risk for complications due to low
blood counts. Umbilical cord blood transplant will be the standard arm for this protocol.
This study uses a new method of bone marrow transplantation called combined
haplo-identical cord (haplo-cord) transplantation. In this procedure, cells from a
related donor who shares half of the HLA proteins ( haplo-identical) are collected from
the blood, as well as cells from an umbilical cord, and then both are transplanted. It is
hoped that by using cells from a haplo-identical relative, subjects will have a faster
recovery and require fewer transfusions. Over time the haplo-identical cells from the
relative are replaced by the cells from the cord blood. The combined transplantation of
haplo-identical stem cells and cord blood has previously been used in approximately 60
subjects with very encouraging results.
Traditionally it has been felt that the most important determinant of outcome of an UCB
stem cell transplant is the cord blood cell dose. The second determinant is the degree of
matching between donor and recipient. Many times, we have difficulty identifying UCB
units of sufficient cell dose that are well matched. Of interest,in our prior study of
haplo-cord SCT indicated outcomes seemed independent of the UCB cell dose. If this
preliminary observation is correct, we may be able to improve the outcomes of haplo cord
transplant further by accepting lower threshold UCB doses and rather focusing on optimal
matching (including matching for HLA and another characteristic called IPA). This is the
primary objective of this study.