Rusalatide acetate (also known as chrysalin or TP 508) is a 23-amino acid peptide derived from human prothrombin; it represents part of the receptor-binding domain of the human thrombin molecule. Rusalatide acetate binds to high-affinity thrombin receptors and mimics cellular effects of thrombin at sites of tissue injury. Rusalatide acetate demonstrated safety and potential efficacy in phase I/II clinical trials for the treatment of diabetic foot ulcers. It interacts with cell surface receptors to stimulate a cascade of cellular and molecular wound healing events, including activation of nitric oxide signaling. In addition, this drug participated in phase II clinical trial to determine the effectiveness of four doses for treating broken wrists in adults. However, this study was terminated because the drug did not demonstrate benefit compared to placebo. Rusalatide acetate was also studied as a cardiovascular drug. However, in January 2012, Capstone discontinued the development of rusalatide, for financial reasons. Recent studies show that a single injection of TP508 (rusalatide acetate) administered 24 h after irradiation significantly increases survival and delays mortality in murine models of acute radiation mortality. Thus, this drug is being developed as a potential nuclear countermeasure.