Recilisib sodium (500 mg/kg) significantly increases the rate of recovery and differentiation of primitive bone marrow myeloid progenitor cells in mice. Recilisib sodium in combination with radiation reduces CFU numbers in mice, but the Recilisib sodium-treated mice consistently retain a capability to form differentiated colonies. Recilisib sodium treated mice have a progenitor cell population that is never completely depleted by radiation exposure[1].