DoD to Conduct Study of Pluristem’s Radiation Exposure Countermeasure

Acute Radiological Syndrome Medical Countermeasure Development
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Pluristem Therapeutics Inc., developer of placenta-based cell therapy products, has announced that a pilot study of the company’s PLX-R18 cell therapy will be initiated by the U.S. Department of Defense’s (DOD) Armed Forces Radiobiology Research Institute (AFRRI), part of the Uniformed Services University of Health Sciences (USU).

The study will examine the effectiveness of PLX-R18 as a treatment for Acute Radiation Syndrome (ARS) prior to, and within the first 24 hours of exposure to radiation. ARS results from exposure to high levels of radiation, such as in the case of a nuclear accident or attack.

PLX-R18 is Pluristem’s second cell therapy product in development. It is designed to treat bone marrow that is unable to produce enough blood cells due to a variety of causes including ARS, certain cancers or cancer treatments, or immune-mediated bone marrow failure. Preclinical data indicates that PLX-R18 cells secrete a range of specific proteins that trigger the regeneration of bone marrow hematopoietic cells, thereby supporting the recovery of blood cell production.

Positive data from studies of PLX-R18 cells as a treatment for ARS conducted by the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health (NIH), U.S. Department of Health and Human Services (DHHS), demonstrated improvement in survival rates and enhancement of blood lineages recovery.

A key difference in the NIAID study and the upcoming DOD study is the timeframe of exposure that is being examined: in the NIAID study, PLX-R18 was administered to subjects 24 hours post exposure, while the new DOD study will be designed to support the needs of the U.S. Armed Forces and examine subjects receiving treatment prior to, or within the first 24 hours of radiation exposure.

The DOD studies will be conducted in parallel with the NIH/DHHS studies, allowing broader understanding of the potential therapeutic effects of PLX-R18 as a novel medical countermeasure for ARS.

The study will be conducted in accordance with the FDA Animal Rule pathway, the regulatory pathway followed when human efficacy trials are not feasible, in this case due to the ethics of exposing humans to nuclear radiation. Product approval via this pathway is granted following large animal efficacy studies and human safety data.

Pluristem’s cell products release a range of therapeutic proteins in response to inflammation, ischemia, hematological disorders, and radiation damage. PLX cell products are grown using the company’s proprietary three-dimensional expansion technology. They are off-the-shelf, requiring no tissue matching prior to administration.