In a head-to-head comparison of 4 standard factor VIII (FVIII) concentrates, boys with hemophilia who switched to Kovaltry® obtained better pharmacokinetic results and fewer bleeds, according to a new study published in Research and Practice in Thrombosis and Haemostasis. The results showed that boys with a higher von Willebrand factor level and the non-O blood group benefitted the most.

“The great interindividual variability in the [pharmacokinetic] profiles of FVIII concentrates leads to different trough levels in patients with the same dosing regimens for prophylaxis,” the researchers wrote. “Thus, the knowledge of widely used FVIII concentrates’ [pharmacokinetic] profiles is vital for a better understanding of the prophylactic regimen in routine prophylaxis and on-demand infusions.”

The study included 47 boys and compared 4 commonly administered FVIII concentrates: Kovaltry, Kogenate®, Advate®, and GreenMono. Twenty-two boys switched from Kogenate, 14 switched from Advate, and the rest switched from GreenMono, all to Kovaltry and all maintaining the same dosing regimen.

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Kovaltry was observed to have a longer terminal half-life time (t1/2)) in all groups, as well as a reduced clearance and longer mean residence time. Due to these enhancements, fewer patients on antihemophilic factor had a trough level of <1 IU/dL, and those with a trough level of 1 to 3 IU/dL and >3 IU/dL increased from 8 to 10 and from 3 to 6, respectively.

In terms of bleeding rates, after the switch to the antihemophilic factor, significantly improved annual bleeding rates, annual spontaneous bleeding rates, and annual joint bleeding rates were reported in the Advate and GreenMono groups. The authors attribute these improvements mainly to the improved t1/2 and decreased reduced clearance.

In the Kogenate group, although significant improvements in bleeding rates were not observed, there was a trend toward reduced bleeds in this group. The authors hope the data obtained in this study will be further investigated with the aim of developing a population pharmacokinetic model for individualized hemophilia prophylaxis in the near future.


Huang, K, Zhen, Y, Li, G, et al. Enhanced pharmacokinetics and reduced bleeds in boys with hemophilia A after switching to Kovaltry from other standard half-life factor VIII concentrates. Res Pract Thromb Haemost. Published online March 25, 2022. doi:10.1002/rth2.12686