Inhibitors Are the Main Treatment Challenge with FVIII Today1
A serious complication in treating hemophilia is the development of inhibitors. Inhibitors are antibodies created by the body's immune system that can reduce the effectiveness of the infused factor used to control or prevent bleeding episodes.
Inhibitors can develop in up to 35% of people with severe hemophilia A who receive factor VIII (FVIII) replacement therapy. Inhibitors attach to FVIII and diminish its ability to stop bleeding. Inhibitors are the most serious and challenging complication of hemophilia A management.1,2
PREVALENCE AND RISK
The risk of inhibitor development in hemophilia A is significant.

~35%
of people with hemophilia A may develop an inhibitor2

~25%
of people with hemophilia A who develop an inhibitor will deal with that inhibitor for life3

~60%
of people, as well as their healthcare providers, were not aware they had an inhibitor, according to a recent study4

ALL
patients with hemophilia A are at risk of inhibitors, regardless of age and disease severity4,5
PREVALENCE AND RISK OF INHIBITORS
The risk of inhibitor development in hemophilia A is significant.

~35% of people with severe hemophilia A may develop an inhibitor2

~25% of people with hemophilia A who develop an inhibitor will deal with that inhibitor for life3

~60% of people, as well as their treatment centers, were not aware they had an inhibitor, according to a recent study4

ALL patients with hemophilia A are at risk of inhibitors, regardless of age and disease severity4,5
WHAT RAISES YOUR RISK OF INHIBITORS?
Some genetic and environmental risk factors are linked to the development of inhibitors.
Risk factors include:
Genetic
- Severity of hemophilia A6
- Large mutation of the FVIII gene7
- Family history of inhibitors7
- Ethnicity7
Environmental
- Intensive FVIII treatment at peak treatment moments6
- Early intensive exposure to FVIII treatment7
- Immunologic/inflammatory/infectious events (eg, vaccination, surgery, illness)7
- FVIII product type2
IMPACT AND HEALTH RISKS
Death due to bleeding-related causes is significantly higher with an inhibitor than without.8,9
Inhibitors also increase the risk of bleeding and joint damage as well as the costs of care.9
2X MORE LIKELY TO BE HOSPITALIZED
People with inhibitors are twice as likely to be hospitalized for a bleeding complication compared to people who have not developed them.4
HIGHER TREATMENT COSTS
Treatment costs for a person with an inhibitor are on average 2 to 10 times higher than costs for a person without inhibitors, and can exceed $1 million annually.4,10
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REFERENCES
- World Federation of Hemophilia. What are inhibitors? http://www1.wfh.org/publication/files/pdf-1343.pdf. Published 2009. Accessed April 1, 2022.
- Peyvandi F, Mannucci PM, Garagiola I, et al. A randomized trial of factor VIII and neutralizing antibodies in hemophilia A. N Engl J Med. 2016;374(21):2054-2064.
- Valentino LA, Kempton CL, Kruse-Jarres R, Mathew P, Meeks SL, Reiss UM. US guidelines for immune tolerance induction in patients with haemophilia A and inhibitors. Haemophilia. 2015:1-9. doi: 10.1111/hae.12730.
- Soucie JM, Miller CH, Kelly FM, et al. A study of prospective surveillance for inhibitors among persons with haemophilia in the United States. Haemophilia. 2014;20(2):230-237.
- Hay CRM, Palmer B, Chalmers E, et al. Incidence of factor VIII inhibitors throughout life in severe hemophilia A in the United Kingdom. Blood. 2011;117(23):6367-6370.
- DiMichele DM. Inhibitors in Hemophilia: A Primer. 4th ed. Montreal, Canada: World Federation of Hemophilia; 2008.
- Carcao M, Re W, Ewenstein B. The role of previously untreated patient studies in understanding the development of FVIII inhibitors. Haemophilia. 2016;22(1):22-31.
- Walsh CE, Soucie JM, Miller CH; and the United States Hemophilia Treatment Center Network. Impact of inhibitors on hemophilia A mortality in the United States. Am J Hematol. 2015;90(5):400-405.
- Medical and Scientific Advisory Council. MASAC recommendation on SIPPET (Survey of Inhibitors in Plasma-Product-Exposed Toddlers): results and recommendations for treatment products for previously untreated patients with hemophilia A. https://www.hemophilia.org/healthcare-professionals/guidelines-on-care/masac-documents/masac-document-243-recommendation-on-sippet-survey-of-inhibitors-in-plasma-product-exposed-toddlers-results-and-recommendations-for-treatment-products-for-previously-untreated-patients-with Published June 28, 2016. Accessed April 1, 2022.
- Ullman M, Hoots WK. Assessing the costs for clinical care of patients with high-responding factor VIII and IX inhibitors. Haemophilia. 2006;12(Suppl 6):74-80.
- Hemophilia Federation of America. Inhibitors. Hemophilia Federation of America website. http://www.hemophiliafed.org/bleeding-disorders/inhibitors/. Accessed April 1, 2022.
- Morfini M, Haya S, Tagariello G, et al. European study on orthopaedic status of haemophilia patients with inhibitors. Haemophilia. 2007;13:606-612.
- Solimeno L, Mancuso M, Pasta G, Santagostino E, Perfetto S, Mannucci PM. Factors influencing the long-term outcome of primary total knee replacement in haemophiliacs: a review of 116 procedures at a single institution. Br J Hematol. 2009;145:227-234.