Date: 2015-02-18
Type of information: Results
phase:
Announcement: results
Company: Pluristem Therapeutics (Israel) National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH) (USA)
Product: PLX-R18 cells (PLacental eXpanded RAD (PLX-RAD) cells)
Action
mechanism: cell therapy. Data from Mechanism of Action Study conducted by NIH: The objective of this study, performed at the Indiana University School of Medicine and funded by the Product Development Support Services Contract HHSN277201000046C from NIAID, was to investigate the mechanism of action behind the results of the NIH’s first study of the efficacy of PLX-R18 in ARS. That first study showed a significantly increased 30-day survival and overall survival time of mice treated with PLX-R18 compared to controls.
In the current study, 256 mice were randomized to be injected intramuscularly with PLX-R18 or placebo after total body irradiation, or PLX-R18 or placebo after sham irradiation. Mice were dosed intramuscularly with PLX-R18 cells or a placebo on day 1 and day 5 post-irradiation. Complete blood count parameters and body weight were measured at 8 post-irradiation time points (days 2, 4, 6, 9, 13, 15, 17, and 23), and bone marrow and spleen cellularity and hematopoietic progenitor cells (HPC) were measured at 6 time points (days 2, 4, 6, 9, 13, and 23). Treatment with PLX-R18 cells significantly increased recovery of white blood cells (p=.0024), neutrophils (p=.0026), monocytes (p=.0272), red blood cells (p<.0001), platelets (p=.0005), hemoglobin (p<.0001), and hematocrit (p<.0001) at day 23 post-irradiation compared with vehicle-treated control mice. Increases in lymphocytes and percent of neutrophils were also observed, but were not statistically significant. The increase in bone marrow progenitor cells was accelerated in mice treated with PLX-R18 cells as compared to the control group, but this was not statistically significant. The population of bone marrow cells responsible for the earlier stages of new red cell, white cell, and platelet production began to increase before those involved in later stages of production; this is consistent with normal physiology in which the progenitor cells proliferate and replenish the more mature cell populations and eventually the peripheral blood cells.
Disease: acute radiation syndrome
Therapeutic area: Hematologic diseases
Country: USA
Trial
details: * On February 3, 2014, Pluristem Therapeutics has announced that the U.S. National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health (NIH), will commence a mechanism-of-action study of Pluristem’s PLacental eXpanded RAD (PLX-RAD) cells for the treatment of acute radiation syndrome (ARS). The study aims to investigate the effect of PLX-RAD cells on body weight, blood count parameters, cytokine concentrations and bone marrow or spleen cellularity at various time points following the administration of PLX-RAD cells to animals receiving total body irradiation. The study is scheduled to begin in February 2014.
The objective of this latest trial was to investigate the mechanism of action behind the significant improvement in survival in irradiated mice treated with PLX-R18 that was demonstrated in the NIH’s first efficacy study. The results of the current study indicate that intramuscular administration exerts a systemic healing effect on bone marrow, lending further support to the concept that Pluristem’s cells work systemically via secretion of therapeutic proteins, although the cells themselves remain in the muscle into which they were initially injected. While additional animal trials are needed prior to FDA approval of PLX-R18 for use in ARS, no human trials would be required because product development is conducted under the FDA’s Animal Rule.
Pluristem is developing PLX-R18 cells for other potential indications including enhancement of engraftment of transplanted hematopoietic stem cells for the treatment of bone marrow deficiency. Trials for this indication are ongoing at Case Western University and Hadassah Medical Center. Data from the NIH studies in ARS are expected to benefit Pluristem’s development of its hematology program.
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