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Click here for ReFacto AF® (moroctocog alfa) Prescribing Information. Adverse event reporting information can be found at the bottom of the page.

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.


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: webprogram/Paper141801.html (Accessed March 2021)
3. NHS. Blood groups. Available at: groups/ (Accessed March 2021)
4. Toutain PL, Bousquet-Mélou A. Plasma terminal half-life. J. vet. Pharmacol. Therap. (2004) 27, 427-439.

Find out how to use the ReFacto AF Laboratory Standard

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Find out about the safety profile of ReFacto AF

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PP-REF-GBR-0256. May 2021

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PP-PFE-GBR-2688. December 2020