PLacental eXpanded (PLX) cells are placenta-derived, mesenchymal-like adherent stromal cells that are designed to be administered to patients without the need for tissue or genetic matching. These cells release soluble biomolecules, such as cytokines, chemokines and growth factors, which act in a paracrine or endocrine manner to facilitate healing of damaged tissue by stimulating the body’s own regenerative mechanisms.
PLX-PAD cells respond to chemical distress signals from tissues that have been damaged by ischemia (inadequate blood flow), muscle trauma, or inflammation, by secreting a range of therapeutic proteins that trigger the body’s own repair mechanisms. These secreted proteins drive the body to grow collateral blood vessels to bring oxygenated blood to ischemic tissue, heal damaged muscle, and dampen inflammation. PLX-PAD cells also modulate the immune system, which plays a central role in the body’s response to injuries.
PLX-PAD is being developed in clinical trials for Critical Limb Ischemia via accelerated regulatory pathways in both Europe and Japan. Pre-marketing “pivotal” trials are expected to start in both regions in 2016. Two completed Phase I trials of PLX-PAD in Critical Limb Ischemia produced positive results, and a randomized, double-blind Phase II study has demonstrated the safety and potential efficacy of PLX-PAD in treating muscle injury in the context of hip replacement surgery. The cells are also being studied in an ongoing Phase II trial in Intermittent Claudication, and are being evaluated for other indications including Preeclampsia.
PLX-R18 cells release a combination of therapeutic proteins in response to a damaged or poorly functioning hematopoietic system; this system creates the blood cells that protect us from infection, uncontrolled bleeding and anemia. The product is currently in development to treat incomplete engraftment of transplanted hematopoietic cells, and Acute Radiation Syndrome (ARS). The U.S. National Institutes of Health’s NIAID is initiating dose evaluation studies of PLX-R18 in ARS as a basis for a potential pre-marketing trial in a large animal model. Positive data from that trial could allow Pluristem to apply for approval of PLX-R18 in this indication using the Animal Rule regulatory pathway. PLX-R18 is also being evaluated in preclinical studies to explore its therapeutic potential to treat a variety of other hematologic indications.