After the first hour of drug administration (from 0 to 60 min), the incorporated radioactivity into thrombi increased from baseline by 73±13, 67±22 and 32±10% in placebo, AP-1 and Napsagatran-treated rabbits, respectively. Statistical analysis confirm that thrombus growth in the placebo and AP-1 treated rabbits is not different. In contrast, reduction of 125I-fibrinogen incorporation by Napsagatran is statistical different from the placebo group (P<0.01)[3].