The level of VWF inhibition correlates with platelet count. The first day after injection of GBR600 (open arrow heads), VWF activity was moderately inhibited in baboon B3 (A) and maximally inhibited in baboon A8 and B6B until day 11 (B-C) and in baboon A7 until day 4 (D). The moderate inhibition of VWF activity in baboon B3 was accompanied by a decrease in platelet counts (E), whereas platelet counts remained stable in baboons A8, BB, and A7 (F-H) when VWF activity was fully inhibited during the first 4 days of the experiment (B-D). GBR600 plasma levels were lower in baboon B3 (I) compared with baboons A8, B6B, and A7 (I-L). In every plasma sample, VWF:RCo/VWF:Ag levels (A-D), and GBR600 levels (I-L) were determined in triplicate and data are represented as mean ± SEM. Platelet counts were only measured once in each blood sample (E-H).