The Hadassah Medical Center’s Department of Bone Marrow Transplantation and Cancer Immunotherapy and Israel’s Pluristem Therapeutics report that in their joint study, mice with damaged bone marrow who received intramuscular injections of Pluristem stem cells (PLX-R18) together with a bone marrow transplant showed significantly faster recovery of blood cell production than those mice given a placebo with their bone marrow transplant.
A rapid return to normal blood cell counts is critical for patients following a bone marrow transplant because until white blood cell and platelet levels return to normal, patients cannot fight infections and are susceptible to hemorrhage. Pluristem Therapeutics, a leading developer of placenta-based cell therapy products, has also been working with Hadassah for several years using its PLX stem cells to treat bone marrow failure and acute radiation syndrome.
In this latest study, the mice were given lethal doses of radiation followed by either a low dose or a high dose of bone marrow cells and either PLX-R18 cells or the placebo. Evidence of more rapid recovery was found at the two earliest data collection time points of the study. Nine days after transplantation with a low dose of bone marrow cells and concurrent administration of either PLX-R18 or placebo, those treated with PLX-R18 showed statistically significant increases in numbers of platelets and granulocytes as compared to the controls.
Principal Investigator Prof. Reuven Or, Director of the Department of Bone Marrow Transplantation and Cancer Immunotherapy at Hadassah, explains: “A statistically significant increase in blood counts soon after bone marrow transplant is very meaningful. For the transplant patient, the most critical period for hematopoietic (blood cell production) recovery is in the days following the transplant. We were particularly encouraged to see that the administration of PLX-R18 cells resulted in the greatest early improvement when using a lower dose of bone marrow cells. This means we could one day potentially achieve success with lower bone marrow transplant doses, thus addressing both treatment costs and donor availability.”
The study also revealed that nine days after transplantation with a high dose of bone marrow cells and concurrent administration of either PLX-R18 or placebo, those treated with PLX-R18 also had statistically significant increases in platelet levels. One week later, at 16 days after a low-dose transplantation, those treated with PLX-R18 cells had more platelets than controls, and those treated with PLX-R18 and a high dose of bone marrow had statistically significant increases in platelets, granulocyte, and total white blood cells.
In parallel with the Hadassah study, a preliminary study was conducted at Case Western Reserve University in Cleveland, Ohio, by Hillard M. Lazarus, MD, Professor of Medicine in the Department of Hematology and Oncology. This study is part of ongoing research there to test PLX-R18 for use in umbilical cord blood stem cell transplantation. Data in eight mice showed that six weeks after exposure to high doses of radiation, followed by transplantation with human umbilical cord blood cells, three out of four mice who received PLX-R18 cells survived compared to only one out of the four who received a placebo after transplant. At eight weeks after irradiation and transplantation, the mice who received PLX-R18 each had a higher percent of blood cells in their peripheral blood than the surviving control subject.
Zami Aberman, Chairman and Chief Executive Officer of Pluristem, comments: “Improving the outcomes of bone marrow and umbilical cord blood transplantation can have a significant impact on the treatment of a range of diseases, from blood cancers to immune and genetic disorders. We are happy with the data from preclinical studies of PLX-R18 in the context of transplantation and look forward to continuing our work in these indications with both Hadassah Medical Center and Case Western University.”