Patients with hemophilia A who switched to BAY 81-8973 (octocog alfa; Kovaltry®) from other standard half-life (SHL) factor VIII (FVIII) products maintained already favorable outcome rates with a possible improvement in half-life, as published in Haemophilia.

The patients enrolled in the study had a median annualized bleeding rate (ABR) and annualized joint bleeding rate (AJBR) of 0 before and after the switch to BAY 81-8973. Before switching treatments, 30 patients (75%) had an ABR of 0, while 33 (82.5%) had an ABR of 0 after switching.

Prior to switching, 10 patients reported bleeds and had a median ABR of 4 and a median AJBR of 2; both median values were 0 after switching, indicating potential improvements in already well-controlled bleeding rates.


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“Our data also showed that the patients overall were well treated with median ABR and AJBR of 0 both prior to and after the switch to BAY 81-8973,” the authors said. “In absolute figures, there was a minor reduction in mean ABR and AJBR rates after the switch to BAY 81-8973, while maintaining the same dose and dosing frequency, but this reduction was not statistically significant.”

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Pharmacokinetic analysis of a subset of 14 patients showed that the Web-Accessible Population Pharmacokinetic Service – Hemophilia estimate of the median half-life for BAY 81-8973 was 20 hours (interquartile range [IQR], 17-26.5) and the median estimated time to 1% was 91.5 hours (IQR, 59.8-143). This half-life was longer than the reported values of other SHL products, the authors said.

The levels of von Willebrand factor (VWF) appeared to play a significant role in the half-lives reported during the study (P =.01), with higher levels leading to shorter half-lives. If the 3 highest and 3 lowest VWF outliers were removed from the analyses, the median half-life of BAY 81-8973 became 13.4 hours (IQR, 11.5-16.5).

“This shows the importance to consider VWF levels when interpreting FVIII [pharmacokinetic] data and reinforces the use of head-to-head cross-over studies when comparing different products,” the authors explained.

Forty patients with hemophilia A were included in the study, with 18 at a hemophilia center in Malmö, Norway, and 22 at a hemophilia center in Oslo. All patients had severe hemophilia A, except for 2 who had moderate hemophilia A. Prior to the switch, 21 patients received Kogenate® (octocog alfa), 13 received Helixate® (octocog alfa), 5 received Advate® (octocog alfa), and 1 received ReFacto® (moroctocog alfa).

Reference

Arvanitakis A, Holme PA, Berntorp E, Astermark J. Clinical outcome and adherence rate in Scandinavian patients with intermediate-intensity prophylaxis before and after the switch of standard half-life FVIII products to BAY 81-8973. Haemophilia. Published online January 10, 2022. doi:10.1111/hae.14489