Thromb Haemost 2014; 112(02): 304-310
DOI: 10.1160/TH13-09-0798
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Sustained pro-haemostatic activity of rFVIIa in plasma and platelets in non-bleeding pigs may explain the efficacy of a once-daily prophylaxis in humans

Anne Marieke Schut
1   Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
,
Agon Hyseni
2   Department of Clinical Chemistry and Haematology, Utrecht University, University Medical Center Utrecht, Utrecht, the Netherlands
,
Jelle Adelmeijer
1   Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
,
Joost C. M. Meijers
3   Departments of Experimental Vascular Medicine and Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands
,
Philip G. de Groot
2   Department of Clinical Chemistry and Haematology, Utrecht University, University Medical Center Utrecht, Utrecht, the Netherlands
,
Ton Lisman
1   Surgical Research Laboratory, Department of Surgery, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
› Author Affiliations

Financial support: This study was supported in part by an unrestricted educational grant from Novo Nordisk.
Further Information

Publication History

Received: 26 September 2013

Accepted after major revision: 08 March 2014

Publication Date:
21 November 2017 (online)

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Summary

Recombinant factor VIIa (rFVIIa) is registered for treatment of inhibitor-complicated haemophilia, and a once-daily prophylactic administration of rFVIIa is successful in reducing the number of bleeding events. This suggests that a single rFVIIa dose has a pro-haemostatic effect up to 24 hours (h), which is difficult to explain given its half-life of 2 h. In this study, six pigs received a 90 µg/kg rFVIIa bolus. Plasma was collected and platelets were isolated at various time points up to 48 h, and analysed for FVIIa levels and associated haemostatic activity. Elevated plasma FVIIa levels were detected up to 24 h post-administration (36 (32–56) mU/ml [median (interquartile range [IQR]), 24 h] vs 2 (2–14) mU/ml [baseline]). Corresponding prothrombin time (PT) values remained shortened compared to baseline until 24 h post-administration (9.4 (9.3–9.9) seconds (s) [24 h] vs 10.5 (10.2–11.0) s [baseline], p ≤0.01). The lag time in thrombin generation testing as well as clotting times in plasma-based assays were shortened up to 12 or 24 h post-administration, respectively (lag times 1.8 (1.7–2.1) minutes (min) [12 h] vs 2.3 (2.3–2.6) min [baseline], p ≤0.01 and clotting times 3.8 (3.2–3.9) min [24 h] vs 5.2 (4.6–5.5) min [baseline], p ≤0.001). Platelet FVIIa levels were elevated up to 48 h (7.7 (3.4–9.0) ng VIIa/mg actin [48 h] vs 2.5 (0.7–4.8) ng VIIa/mg actin [baseline]). In conclusion, elevated and haemostatically active plasma and platelet FVIIa levels are detectable up to 24–48 h following rFVIIa administration in pigs. This prolonged pro-haemostatic effect of FVIIa may explain the prophylactic efficacy of a once-daily rFVIIa treatment.