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Not all half-lives are the same in haemophilia A resulting in 1 in 3 patients not receiving their desired improvement1

Each patient with haemophilia A has their individual pharmacokinetic profile that must be taken into consideration when making a decision regarding their treatment.1

A recent analysis of more than 550 severe haemophilia A patients revealed1:

  • At a group level, terminal half-life* (THL) extension for haemophilia A was observed when switching from a standard half-life (SHL) to an extended half-life (EHL) factor VIII (FVIII) for both children and adults with the median increasing by 4.1 hours (interquartile range (IQR): 2.0-6.7)
  • However, 27% of the patients saw less than 20% improvement and 10% of the patients had a shorter THL while taking an EHL compared to the THL of SHL FVIII.​​​​​​​

Terminal half-lives in haemophilia A patients after switching from SHL to EHL FVIII concentrate
Adapted from Versloot O, Iserman E, Chelle P, et al. Blood (2020) 136 (1): 21–22.1

Additional analysis of 4,300 severe haemophilia A patients confirmed2:

  • Median THL was longer in EHL at 15.1 hours (IQR: 12.0-19.0) vs. 11.1 hours (8.8-14.2) in SHL FVIII for both children and adults, resulting in a median increase of 4.0 hours.

It also showed that for patients with severe haemophilia A2:
  • The THL was 2.2 hours shorter in patients with blood group O, independent of concentrate type
    (48% of UK population has blood group O3)
  • In people with a positive inhibitor history, the THL was decreased by 1.3 hours

* Terminal half‐life (THL) is the time required for the plasma concentration of medicine to fall by 50% during the terminal phase, and not
the time required to eliminate half the administered dose4.

References:

1. Versloot O, Iserman E, Chelle P, et al. Not All Patients Benefit from Switching to Ehl: Results from the Wapps Database. Blood (2020) 136 (Supplement 1): 21–22.
2. Versloot O, Iserman E, Chelle P, et al. 235 Terminal Half-Life of Factor VIII/IX According to Age and Blood Group Based on 8550 Assessments. Oral session 322 at the 62nd ASH Annual Meeting and Exposition 2020. Available at: https://ash.confex.com/ash/2020/ webprogram/Paper141801.html (Accessed March 2021)
3. NHS. Blood groups. Available at: https://www.nhs.uk/conditions/blood groups/ (Accessed March 2021)
4. Toutain PL, Bousquet-Mélou A. Plasma terminal half-life. J. vet. Pharmacol. Therap. (2004) 27, 427-439.

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PP-REF-GBR-0256. May 2021

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