Developing a bank of purified myeloid progenitor cells as a bridging therapy for transient pancytopenia resulting from radiation injury

ABSTRACT Exposure to even moderate levels (<3 Gy) of ionizing radiation can result in severe pancyotopenia, placing patients as wells as victims of accidental exposure at high risks for infection and uncontrolled hemorrhaging. Accidental exposure differs from radiation therapy in that biodosimetry (e.g., type of radiation, dose and dose rate) is often uncertain; consequently, the optimal treatment regimen to ameliorate the effects of radiation is not immediately evident. Therefore, victims of accidental ionizing radiation exposure would benefit from bridging therapies to traverse extended periods of neutropenia and thrombocytopenia until the optimal course of medical care can be determined. Ossium Health proposes to develop a bank of myeloid committed progenitors (MCP) from deceased donor bone marrow (BM). The strategy employs commercially available GMP- compliant, closed-system flow separation device to specifically select MCP from whole BM based on defining cell surface markers CD34+CD38+. The proposed Phase II studies build on our previously successful Phase I, demonstrating our ability to select highly pure MCP from whole BM from deceased organ donors. In this phase we will refine selection and expand the pool of donor BM that can be used. The cells will be validated in vitro and in vivo in an immunocompromised mouse hematopoietic-acute radiation syndrome model to demonstrate enhanced survival. The overall product of this research program will be a compelling preclinical package to justify definitive studies to support FDA approval under the Animal Rule for a novel radiation/nuclear mass casualty medical countermeasure bridging therapy. Commercial viability for both medical countermeasures and civilian uses is enhanced by the up to 5-fold lower cost for manufacturing compared to current technologies.