Pluristem Therapeutics Inc., a leading developer of placenta-based cell therapy products, has announced that the National Institute of Allergy and Infectious Diseases (NIAID), a part of the U.S. National Institutes of Health (NIH), will initiate studies in large animals to evaluate dosing for Pluristem's PLX-R18 as a medical counter measure in the treatment of the hematologic components of Acute Radiation Syndrome (ARS). Once the optimal dose is determined in large animals, a pivotal trial could be conducted and the results used to support a Biologics License Application (BLA) submission of PLX-R18 for this indication under the Animal Rule regulatory pathway. In September 2015, the FDA had confirmed that data from earlier trials conducted by NIAID were sufficient for the future design of studies in Pluristem's development path for PLX-R18. NIAID is supporting and collaborating on the dosing studies, and Pluristem is supplying PLX-R18.
ARS is caused by exposure to very high levels of radiation, such as those that could occur in a nuclear catastrophe. The syndrome can cause severe illness or death. When human trials are not ethical or feasible, as in this indication, the FDA's Animal Rule regulatory pathway allows for the determination of the efficacy of drugs using animal efficacy studies and human safety data.
"We are very pleased to receive the support and collaboration of the NIH for the development of PLX-R18 as a medical countermeasure in the treatment of ARS, which is the first indication we are targeting in the defense technology space," stated Pluristem Chairman and CEO Zami Aberman.
Pluristem recently received FDA clearance to initiate a Phase I trial of PLX-R18 to treat incomplete hematopoietic recovery following Hematopoietic Cell Transplantation (HCT). This trial is scheduled to begin in the first half of 2016 in the U.S. Additionally, Pluristem has entered into a Memorandum of Understanding (MOU) with Japan's Fukushima Medical University, Fukushima Global Medical Science Center to develop PLX-R18 for the treatment of ARS and for morbidities following radiotherapy in cancer patients.
Previous NIH/NIAID studies of PLX-R18 in ARS
The NIH has supported and completed two mouse studies of PLX-R18 as a potential treatment of the component of ARS that affects bone marrow function. ARS involves severe, potentially lethal damage to the bone marrow's ability to produce blood cells and platelets, as well as to other systems and organs. Severe damage to bone marrow quickly makes victims vulnerable to life-threatening hemorrhage, infection and anemia. A recently concluded NIH/NIAID study showed that administration of PLX-R18 resulted in a statistically significant improvement in the recovery of white blood cell, red blood cell, and platelet levels in animals exposed to high levels of radiation, and described the treatment's mechanism of action. The NIH/NIAID's first study of PLX-R18 showed a substantial, statistically significant improvement in 30-day survival and overall survival of irradiated rodents given PLX-R18 versus a control group.
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. Pluristem received FDA clearance to initiate a Phase I trial of PLX-R18 in incomplete bone marrow recovery following hematopoietic cell transplantation. With its capabilities, PLX-R18 could potentially treat a broad range of hematologic indications, which together constitute a substantial global market.