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ReFacto AF (moroctocog alfa) Prescribing Information for Great Britain click here. ReFacto AF (moroctocog alfa) Prescribing Information for Northern Ireland click here.
Adverse event reporting information can be found at the bottom of the page.


​​​​​​ReFacto AF® (moroctocog alfa) is indicated for the treatment and prophylaxis of bleeding in patients with haemophilia A (congenital factor VIII deficiency). ReFacto AF® is appropriate for use in adults and children of all ages, including newborns. ReFacto AF® does not contain von Willebrand factor, and hence is not indicated in von Willebrand's disease.1

Monitoring

ReFacto AF® Laboratory Standard allows for consistent results regardless of assay type.1,2 

​​​​​​​Using a product specific laboratory standard can reduce the discrepancies between the chromogenic substrate assay (CSA) and the one-stage assay (OSA).2

During the course of treatment, appropriate determination of factor VIII levels is advised to guide the dose to be administered and the frequency of repeated infusions.1

When monitoring patients' factor VIII activity levels during treatment with ReFacto AF®, use of the chromogenic assay is recommended.1

Dose based on bodyweight may require adjustment in underweight or overweight patients. Individual patients may vary in their response to factor VIII, demonstrating different half-lives and recoveries.1

In the case of major surgical interventions in particular, precise monitoring of the substitution therapy by means of coagulation analysis (plasma factor VIII activity) is indispensable.1

When using an in vitro thromboplastin time (aPTT)-based one-stage clotting assay for determining factor VIII activity in patients' blood samples, plasma factor VIII activity results can be significantly affected by both the type of aPTT reagent and the reference standard used in the assay. Also there can be significant discrepancies between assay results obtained by aPTT-based one-stage clotting assay and the chromogenic assay. Typically, one-stage clotting assay results are 20–50% lower than the chromogenic substrate assay results. The ReFacto AF® laboratory standard can be used to correct for this discrepancy. This is of particular importance when changing the laboratory and/or reagents used.1  ​​​​​​​

Monitoring

Why should a product-specific laboratory standard be used?

Using a product-specific laboratory standard can reduce the discrepancies between the chromogenic and one-stage assay.2 The use of the ReFacto AF® Laboratory Standard allows for consistent results regardless of assay type.1,2

When monitoring patients' factor VIII activity levels during treatment with ReFacto AF®, the use of a chromogenic substrate assay is recommended. Typically, the chromogenic assay yields results that are higher than those observed with use of the one-stage clotting assay.1

​​​​​​​When to use the ReFacto AF® Laboratory Standard

The ReFacto AF® Laboratory Standard was created for use with the one-stage clotting assay (or the chromogenic assay), when testing plasma samples from patients receiving ReFacto AF®.2 It can be used exactly as you would use a normal (plasma-based) laboratory standard.1


How to prepare the ReFacto AF® Laboratory Standard6

​​​​​​​There are 3 steps involved in preparing the ReFacto AF® Laboratory Standard. 


Step 1

  • Reconstitute the ReFacto AF®​​​​​​​ Laboratory Standard at room temperature using 1.0mL of sterile water​​​​​​​
  • After reconstitution, the vial contents should be transferred to a plastic tube with a stopper
  • The reconstituted ReFacto AF®​​​​​​​ Laboratory Standard solution should be maintained at room temperature and then used within 2 hours*
    ​​​​​​​

    ​​​​​​​* The reconstituted ReFacto AF® Laboratory Standard is stable for 2 hours

    Unopen vials should be stored at -20ºC

    Do not use the vial if there is a lack of vacuum when opening
    ​​​​​​​
Step 2

  • The Refacto AF® Laboratory Standard should be prediluted in factor VIII-deficient (haemophilic or artificially depleted) plasma containing normal functional levels of von Willebrand factor to yield a 1.0IU/mL solution
  • The prepared standard should be used once and discarded
  • ​​​​​​​DO NOT REFREEZE
Step 3

  • The working ReFacto AF® Laboratory Standard solution can now be used to create a standard curve for analysis of plasma samples from patients treated with ReFacto AF®
  • Once the standard curve is established, analysis samples from patients treated with ReFacto AF® may begin
  • Discard all unused materials following universal precautions​​​​​​​​​​

Why, when and how to use the ReFacto AF® Laboratory Standard

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Administration and storage

ReFacto AF® administration allows all-in-one reconstitution of factor VIII.1

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Flexible dosing  

No two days are the same. No two patients are the same. ReFacto AF® offers frequent, flexible dosing so your patients are covered for everyday life.1,3,4

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Patient satisfaction with the FuseNGo

ReFacto AF® (and ReFacto®) have reliably supported you and your patients for over 20 years.1

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ReFacto AF® Laboratory Standard PDF

Contact us to request information on how to use the ReFacto AF Laboratory Standard.

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ReFacto AF® in the real-world setting

rFVIII products like ReFacto AF® are effective at preventing bleeds in everyday settings.5

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Contact us

Contact a member of the Pfizer haemophilia team.

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References
  1. ReFacto AF® Summary of Product Characteristics. For Great Britain, available here. For Northern Ireland, available here.
  2. Ingerslev J et al. J Thromb Haemost. 2004;2(4):632-638.
  3. Shapiro AD et al. Haemophilia 2005;11:571–582.  
  4. Berntorp E, Andersson N. Semin Thromb Hemost. 2016;42:518–525.  
  5. Chhabra A et al. Blood Coagul Fibrinolysis 2020;31(3):186–192.
  6. ReFacto AF Laboratory Standard Flyer (material held internally and available upon request via the Contact Us page)   
Adverse events should be reported. Reporting forms and information can be found at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
​​​​​​​Adverse events should also be reported to Pfizer Medical Information on 01304 616161.

PP-REF-GBR-0269. September 2021.

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PP-PFE-GBR-3863. November 2021

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