If your child is diagnosed with an inhibitor, it can feel scary and overwhelming. Know that there are treatment options available, as well as support from experts and other parents and caregivers going through the same thing. This section will focus on the treatments available for those with hemophilia A or hemophilia B with an inhibitor. If your child has another bleeding disorder with an inhibitor, please work directly with your child’s health care provider to discuss options.
It can be helpful to think about two different goals when dealing with an inhibitor. Goal 1 is to prevent and treat bleeds. Goal 2 is to permanently remove the inhibitor.
Goal 1: Prevent and treat bleeds
There are three main ways to treat and prevent bleeds for people with inhibitors:
For those with hemophilia A (factor VIII [8]), emicizumab is an option to prevent bleeding. It is not an option for those with hemophilia B (factor IX [9]). It is given by injection just below the skin's surface (subcutaneously).
Emicizumab, brand name Hemlibra®, has been shown to greatly reduce the number of bleeds for those who take it.1
Emicizumab was first FDA approved treatment for use in patients with an inhibitor
Emicizumab cannot be used to treat bleeds. If your child has a bleed, they will need to treat the bleed with clotting factor or a bypassing agent (see sections below). This is important to know for emergencies or to plan for medical procedures.2
If your child is on emicizumab make sure to work closely with their health care provider when using bypassing agents to treat bleeds. This may increase the risk of developing a blood clot.2
This product does not treat the inhibitor or get rid of it.
Emicizumab may affect some lab blood tests, including tests to measure factor activity levels and inhibitor titers. Individuals taking emicizumab must be tested with a Chromogenic assay to get a real inhibitor result.2 To learn more about testing for an inhibitor and inhibitor titers, please visit What is an Inhibitor?.
For more information on how emicizumab works in the body and other key questions, please visit Bispecific Antibody Therapy.
People with low-responding inhibitors may be able to treat and prevent bleeds by using larger amounts of clotting factor. Although some factor binds to the inhibitor and becomes inactive, enough is left to help form a clot.3
Your child’s healthcare provider would guide you on when and how to use higher dose factor if appropriate.
Bypassing agents treat bleeding in people with low or high amounts of inhibitors. Instead of replacing the missing factor (factor VIII [8] or factor IX [9]), they go around (or bypass) the inhibitor to help the body form a normal clot.
There are two main types of bypassing agents:
Activated prothrombin complex concentrate, or aPCC (brand name Feiba®), which are used to prevent and treat bleeds4.
Recombinant activated factor VIIa (7a) concentrate (brand names SevenFact®, Novoseven®), which are used to treat bleeds4.
Bypassing agents can be very effective. They also do have some drawbacks.
It can be hard to judge how well a medication is working. Different patients respond differently to the two types of bypassing agents and there is no standard lab test to tell how well a bypassing agent is working to prevent a bleed. There can be some trial and error in finding the right treatment and right dosing.
Recombinant factor VIIa (7a) requires frequent infusions. aPCCs require the product to be infused very slowly, resulting in long infusions, to avoid potential reactions that may result from infusing too quickly. These may contribute to difficulty accessing veins.
If your child is using bypassing agents, make sure to work closely with their health care provider to make sure their blood is not clotting too much or clotting in the wrong place in the body. Certain medications should not be used with some bypassing agents for this reason.4
Goal 2: Permanently Remove the Inhibitor
Prevention and treatment of bleeds is only part of managing an inhibitor. Your child’s health care provider will also likely talk to you about ways to get rid of the inhibitor altogether.
The goal of ITI therapy is to stop the inhibitor reaction from happening.4 In a way, it teaches the body to accept clotting factor treatments.
With ITI therapy, people receive large amounts of clotting factor daily for many weeks or months.
For many people, especially young children, a port (a surgically inserted device to help give clotting factor through a vein) may be needed if it is difficult to find a vein to infuse. Ports can make a person more likely to develop an infection, so it is important to talk to your child’s health care provider before one is inserted.
Often, ITI does get rid of the inhibitor. However, patients may need to continue taking frequent, large amounts of factor for many years to keep the inhibitor from returning. For others, it can reduce the bleeding complications.
ITI therapy requires specialized medical expertise, is costly, and may take a long time to work. It is important to talk through all these factors with your child’s health care provider to make a plan that works for your child and your family.
Resources
Managing inhibitors can be about a lot more than just treatment. Here are some resources for you.
https://www.bleeding.org/sites/default/files/document/files/living-with-inhibitors.pdf
Oldenburg, J., Mahlangu, J., Kim, B., Schmitt, C., Callaghan, M. J., Young, G., Santagostino, E., Kruse-Jarres, R., Negrier, C., Kessler, C. M., Valente, N., Asikanius, E., Levy, G. G., Windyga, J., & Shima, M. (2017). Emicizumab Prophylaxis in Hemophilia A with Inhibitors. The New England Journal of Medicine, 377(9), 809–818. https://doi.org/10.1056/nejmoa1703068
NHF’s Medical and Scientific Advisory Council (MASAC). (2022). MASAC Document 268 - Recommendation on the Use and Management of Emicizumab-kxwh (Hemlibra®) for Hemophilia A with and without Inhibitors (MASAC 268). National Hemophilia Foundation. https://www.hemophilia.org/healthcare-professionals/guidelines-on-care/masac-documents/masac-document-268-recommendation-on-the-use-and-management-of-emicizumab-kxwh-hemlibrar-for-hemophilia-a-with-and-without-inhibitors
Inhibitors | Hemophilia | NCBDDD | CDC. (2020, July 22). Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/hemophilia/inhibitors.html
NHF’s Medical and Scientific Advisory Council. (2022). MASAC Recommendations Concerning Products Licensed for the Treatment of Hemophilia and Other Bleeding Disorders (MASAC 272). National Hemophilia Foundation. https://www.hemophilia.org/healthcare-professionals/guidelines-on-care/masac-documents/masac-document-272-masac-recommendations-concerning-products-licensed-for-the-treatment-of-hemophilia-and-other-bleeding-disorders