HAPC1573 improves coagulation of human plasma deficient of different types of coagulation factors, respectively, in a dose-dependent manner. Coagulation factor–deficient human plasma and normal human plasma were incubated with 0.1 to 100 μg/mL of HAPC1573 (1573) and Protac, a protein C activator, for 15 minutes, and CaCl₂ was added to trigger clotting formation. The clotting time was recorded by an automated analyzer, and data represent the average of duplicates. Dot lines in each assay represent the clotting time without Protac. The coagulation factors deficient in the plasma are as indicated in the top-right corner of each chart. The FV-deficient plasma contained 5% of normal plasma; the FX-deficient plasma contained 1% of normal plasma.