Imagine a scenario where cells and tissues can be engineered to secrete a range of therapeutic proteins that can help the body generate its own healing process.
“These concepts are no longer the stuff of science fiction,” the US Food and Drug Administration said in a statement in mid-November. “We’ve seen improbable advances that hold out great hope for patients.”
The FDA’s declaration came on the heels of the release of a report by the FDA’s Center for Biologics Evaluation and Research that details recommendations for how to expedite the development and review of such cell therapies, including certain regenerative medicine therapies that could be used to treat patients in times of national disasters.
A company that is at the forefront of this field is Haifa-based Pluristem Therapeutics, and its PLX cell therapy products. The cell products are grown using the company’s proprietary 3D expansion technology and can be administered to patients without tissue matching or immunosuppression. The cells release a range of therapeutic proteins in response to inflammation, ischemia, muscle trauma, hematological disorders and radiation damage, and are being tested in late-stage clinical trials.
PLX-R18, the second cell therapy product developed by Pluristem, is unique in that a simple injection of the cells into the muscle induces the victim’s body to create new blood cells, repopulating his or her blood system.
The fear of a nuclear attack led The US National Institutes of Health to collaborate with Pluristem to test the effectiveness of its PLX-R18 cell therapy as a novel medical countermeasure for what is called acute radiation syndrome, which occurs as the result of a nuclear accident or attack and can lead to severe health consequences, including death, said Dr. Arik Eisenkraft, former head of the Medicine Branch of the Chemical, Biological, Radio-Nuclear Protection Division at the Defense Ministry, who currently serves as Pluristem’s director of homeland defense projects.
Eisenkraft said patients with ARS start out with flulike symptoms, but eventually, if left untreated or not treated effectively, ARS attacks a person’s three blood lineages – white and red blood cells and platelets – putting the individual at risk. Low white blood cell count reflects a weakened immune system, making an individual vulnerable to infection. Red blood cells carry oxygen to the body, so we cannot live without them.
Platelets are responsible for coagulation, preventing internal bleeding.
The studies, conducted and funded by the NIH, were carried out in accordance with the FDA’s Animal Rule pathway approval process, the regulatory pathway followed when human efficacy trials are not feasible (in this case due to ethics of exposing humans to nuclear radiation), and has already shown promise.
A phase II equivalent study reported last May demonstrated improved survival and hematological recovery of non-human primates exposed to high levels of radiation. The subjects that received the PLX-R18 treatment experienced an 85% survival rate, compared to a 50% survival rate in the placebo-treated control group. It also shortened the length of time spent below the severe blood count threshold, thus avoiding serious infections, hemorrhage and anemia.
Following the publication of these promising results, Pluristem was also approached by the US Department of Defense (DoD) to examine whether PLX-R18 can also be an effective treatment when administered prior to and/or within 24 hours of exposure to high levels of radiation, specifically for military personnel serving in potentially hostile environments that could contain large amounts of nuclear radiation.
PLX-R18 is an example of the new therapies the FDA is looking to fast-track as part of its efforts to “prioritize the needs of war fighters for medical products that can help save lives on the battlefield,” as the US commissioner of Food and Drugs Scott Gottlieb wrote on Twitter recently.
“We are working on a plan to implement these new pathways in a robust and expedited fashion, in order to quickly meet the needs of the Pentagon and fulfill the commitments we’ve made to Congress and the obligations they’ve entrusted in us,” he tweeted. “In collaboration with partners at DoD, we’ll create an enduring pathway for efficient development and prioritization of products intended to save lives of American military personnel.”
According to Eisenkraft, if the DoD and NIH studies go as planned, PLX-R18 could be on the market within a year.
PLX-R18 stands out because of its high safety profile, meaning that it can also be given to people exposed to low levels of radiation or none at all.
“Our cells are smart cells, so they know how to sense the situation in the body and will induce an increase in blood counts only if it is needed,” said Pluristem’s president and co-CEO, Yaky Yanay. “This can be very useful in the case of mass casualty incidents, when you don’t have the luxury of screening.”
Because the cells are an “off-the-shelf” product that doesn’t require the matching of tissues between the donor and recipient, they can be administered instantly and in the field in the event of a multiple-casualty nuclear attack.
“In view of the therapeutic effects of our product and the current geopolitical situation, governments can potentially shield their citizens from the dire health effects arising from exposure to nuclear radiation, saving many lives in the process,” said Yanay.
Eisenkraft said he believes that once PLX-R18 hits the market, governments will purchase and add it to their disaster recovery supplies. He said each placenta can make tens of thousands of vials of Pluristem PLX cells. Each tiny vial holds hundreds of millions of cells. Very few vials are needed to treat a person.
“This will fill a major gap in how we treat patients exposed to radiation,” he said.
PLX-R18 could also fill other medical care gaps, far beyond treating victims of nuclear incidents, said Yanay. Related studies indicate that this cell product could be used as a treatment for additional indications relating to bone marrow deficiencies, such as those that may occur due to bone marrow failures, radiotherapy, chemotherapy, adverse drug reaction and some genetic conditions. This could mean better treatment options for millions of patients worldwide.
Yanay said Pluristem hopes to continue to broaden collaborations with its strategic partners in the United States.
“We are proud to have been chosen by the US government in their pursuit to obtain a novel countermeasure for ARS to protect US civilians as well as the armed forces,” said Yanay. “We are seeing more and more interest from other governments and hope to be able to provide a better solution for radiation catastrophes worldwide.”