A review of radiation countermeasures focusing on injury-specific medicinals and regulatory approval status: part II. Countermeasures for limited indications, internalized radionuclides, emesis, late effects, and agents demonstrating efficacy in large animals with or without FDA IND status

Purpose: The threat of a radiological/nuclear event is a critical concern for all government agencies involved in national security and public health preparedness. Countermeasures that are safe, easily administered, and effective at diminishing or eliminating adverse health effects to individuals and the overall public health impact of radiation exposure are urgently needed. Radiation countermeasures included in this three-part series have been classified under various subheadings based specifically on their developmental stages for United States Food and Drug Administration (FDA) approval. We have included FDA-approved agents for acute radiation syndrome (ARS) in part I. This is part II in which we have reviewed FDA-approved agents for limited indications, internalized radionuclides, emesis, late effects, radiomitigators available in the strategic national stockpile (SNS), agents with FDA investigational new drug (IND) status, and those with NHP efficacy data without FDA IND. Agents discussed in part III are those agents that have been peer reviewed, published, and have demonstrated significant survival benefits in animal models of ARS. Agents investigated in in vitro models only or studied in animal models without peer-reviewed publications have not been included. Conclusions: The dearth of FDA-approved radiation countermeasures has prompted intensified research for a new generation of radiation countermeasures. A number of promising radiation countermeasures are currently moving forward with continued support and effort by both governmental agencies and by publicly and privately held pharmaceutical companies. There is a limited number of countermeasures which are progressing well following the Animal Rule and may get approved in the near future, thus serving to close the gap of this critically important, unmet radiobiomedical need.