Relationship between mean unbound FXa inhibitor plasma concentration and anti-FXa activity on day 6. Group mean of anti-FXa activity is plotted against unbound rivaroxaban (A) and edoxaban (B) for andexanet alfa–treated subjects at each time point on day 6, between pre–andexanet alfa and 21 hours post–andexanet alfa bolus. Day 6 was the last dose of the inhibitor and the day when andexanet alfa was administered. Total inhibitor concentrations were increased after andexanet alfa administration, as shown in Figures 1 and 2. The solid line represents the best linear regression; the dashed lines indicate the 95% confidence intervals.