Pluri Inc. announced the U.S. National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), has exercised its option for year two of the three-year $4.2 million contract it entered into with Pluri in July 2023. During the 12 months from July 1, 2024 through June 30, 2025, the NIAID will provide $1.4 million for the Company to manufacture the PLX-R18 cell therapy and to conduct both in vitro and in vivo studies to develop PLX-R18 as a potential novel treatment for hematopoietic complications of the acute radiation syndrome (H-ARS). H-ARS is caused by exposure to life-threatening amounts of ionizing radiation, such as that which may occur during a radiological or nuclear accident, terrorist activities, and/or warfare.

The condition is characterized by dose-dependent bone marrow depression, leading to neutropenia, thrombocytopenia, and anemia, and possibly death. The U.S. Food and Drug Administration (FDA) previously approved an Investigational New Drug application for PLX-R18 for the treatment of H-ARS in the case of nuclear or radiological or incidents and granted it Orphan Drug Designation. Over the past year, Pluri has collaborated with the U.S. Department of Defense?s (DoD) Armed Forces Radiobiology Research Institute at the Uniformed Services University of Health Sciences in Bethesda, Maryland, resulting in significant advancements in the development of PLX-R18 as a potential treatment for H-ARS.

PLX-R18 has been safely tested in both humans and animals. Prior studies funded by the NIH/NIAID and conducted in accordance with the FDA?s Animal Rule pathway demonstrated that PLX-R18 administered to animals after radiation exposure for H-ARS significantly increased survival rates from 29% in the control group to 97% in the treated group (p<0.001). Studies conducted by the DoD have shown that PLX- R18, administered as a prophylactic measure 24 hours before radiation exposure, and again 72 hours after exposure, resulted in a significant increase in survival rates, from 4% survival in the placebo group to 74% in the treated group (log-rank test p< 0.0001).

In addition, the data show a significant increase in recovery of white blood cell (p = 0.0047), platelet (p = 0.0070), neutrophil (p = 0.0003) and lymphocyte (p = 0.0025) counts compared to administration of vehicle, and also demonstrate a favorable safety profile. PLX-R18 was tested in humans with incomplete hematopoietic recovery following hematopoietic cell transplantation and was well tolerated with a favorable safety profile. Patients treated with PLX-R18 showed an increase in all three blood cell types compared to the baseline with platelet (p<0.001), hemoglobin (p=0.02) and neutrophil (p=0.15) levels increasing as early as 1 month following PLX-R18 administration and enduring up to 12 months following treatment, while experiencing a significant reduction in mean number of transfused units from a monthly 5.09 to 0.55 for platelets (p=0.045) and 2.91 to 0 for red blood cells (p=0.0005) over 12 months of follow-up.