Apixaban unbound and total concentrations. Plasma concentrations of unbound apixaban before and after andexanet administration in cohorts 1 to 3 (A) and 4 to 6 (B), and total plasma concentration of apixaban in cohorts 1 to 3 (C) and 4 to 6 (D) of the phase 2 study. Values are means ± standard error of the mean.