Victims of acute radiation exposure are likely to experience a range of late multi-organ toxicities, which are collectively referred to as delayed effects of acute radiation exposure (DEARE). Currently there are no FDA-approved MCMs for DEARE. Lisinopril is a lead candidate MCM for mitigation of DEARE as it meets all the technical requirements for MCM development under this BAA including prior efficacy in animal studies and an established safety profile in humans. Our main objective is to build on our extensive preclinical experience to forward lisinopril through FDA-licensure as a countermeasure for DEARE. To meet this objective, we have developed the following three milestones. Milestone 1: Lisinopril dose optimization for mitigation of radiation pneumonitis. Milestone 2: Lisinopril efficacy in survivors of hematologic acute radiation syndrome (H-ARS). Milestone 3: Regulatory Activities.