Summary
- Current bispecific antibody therapies are a type of non-factor therapy used for people with haemophilia A.
- Non-factor therapies don’t replace clotting factor – they support the body to clot in other ways.
- They work by maintaining a constant level of protection against bleeding.
- These therapies are injected under the skin (subcutaneously).
- They are only used as prophylaxis (preventive treatment). If you have a bleed, you will need clotting factor replacement therapy to treat it.
What are bispecific antibody therapies?
Current bispecific antibody therapies are a type of non-factor therapy used for people with haemophilia A.
Haemophilia occurs when a person doesn’t have enough of a specific clotting factor in their blood to control bleeding properly. A clotting factor is a protein in blood that controls bleeding.
When a person has an injury that causes bleeding, more than 20 proteins are involved in the chain reaction to make a clot that stops the bleeding, including multiple clotting factors.
- People with haemophilia A don’t have enough clotting factor VIII (8).
- People with haemophilia B don’t have enough clotting factor IX (9).
Non-factor therapies don’t replace factor VIII or factor IX like clotting factor replacement therapy. Instead, they support the body to clot in other ways.
Examples of bispecific antibody therapies include:
- emicizumab (Hemlibra®)
- Mim8 (in clinical trial)
How these therapies work
Antibodies are proteins that can bind to other proteins. Bispecific antibodies are special because they can attach to 2 different proteins at once. As a treatment for haemophilia A, they act as a bridge between 2 important clotting proteins in the body – factor IXa (9a) and factor X (10). This helps the blood to clot properly, mimicking the action of the missing factor VIII (8).
Bispecific antibody therapies are sometimes called factor VIIIa (8a)-mimetics because they mimic or imitate the function of factor VIII in the clotting chain reaction.
Unlike clotting factor replacement therapy, these therapies do not change your clotting factor levels. Instead, they maintain a constant level of protection, similar to having mild haemophilia.
In clinical studies people on bispecific antibody therapy have ranged from 0 to a median of 1.5 bleeding episodes (bleeds) per year.
How the treatment is given
Bispecific antibody therapies are liquids given as an injection just under the skin (subcutaneously). You do not need to find a vein, and it takes about a minute.
You can be trained to do the injection at home yourself or it can be done by a nurse or doctor in a hospital, a clinic or a care home. You can keep a stock of treatment at home to inject according to your treatment plan. Your stock of treatment vials should usually be kept in a fridge but if they haven’t been opened, you can keep them at room temperature (under 30°C) for a combined total of 7 days.
The treatment schedule is personalised and can range from weekly to monthly.
With emicizumab the dose depends on your weight and how often you have the treatment.
- In discussion with your doctor, you can choose to have it every 1, 2 or 4 weeks.
- It starts with a loading dose: one injection per week for the first 4 weeks.
If you have an injury with a breakthrough bleed or need surgery, you may also need extra treatment with clotting factor replacement therapy. Your haemophilia treating team will guide you on this.
Personalised treatment plans
Treatment for haemophilia is usually prescribed by a haematologist (a doctor who specialises in blood diseases) or a haemophilia nurse practitioner at a Haemophilia Treatment Centre (HTC).
Haemophilia treatment plans are personalised. These plans are developed specifically for you and your circumstances and can be updated whenever needed. Your treatment plan may include a plan for regular prophylaxis treatment and a plan for injuries or surgery.
Australian governments fund a range of clotting factor and other blood products used to treat haemophilia through the National Blood Authority. This means the approved products are provided at no cost to patients who need them.
Treatment safety
All medicines can have side effects. In general, there are not many safety concerns with bispecific antibody therapies.
The most common initial side effects with emicizumab are redness, swelling or itching at the spot where you had the injection, headaches and joint pain. These happen in about 1 in 10 people.
Bispecific antibody therapies increase the potential for your blood to clot. For people with inhibitors, there is a risk of serious blood clots if emicizumab is used alongside treatment with activated prothrombin complex concentrate (aPCC/FEIBA-NF®), another blood product used to help control bleeding.
It is uncommon, but a small number of people can develop anti-drug antibodies to bispecific antibody therapies that cause the treatment not to work as well. If this occurs, your haemophilia treating team will monitor you carefully and may switch you to a different treatment.
New and emerging treatments
Researchers are always looking for new ways to treat haemophilia. Non-factor therapies are still a relatively new treatment option for haemophilia and there is ongoing research and development to improve these types of therapies.
Keep in touch with your HTC to find out what’s new, discuss your treatment options and determine which one would be best for you. You can also stay up to date with new and emerging treatments through Haemophilia Foundation news, websites and education sessions, including the Australian Bleeding Disorders Conference.
Living well with haemophilia treatment
Managing your haemophilia treatment well can help you enjoy a full life. Big treatment changes can also affect mental health, even when the results are positive. Your HTC is there to give advice and support. They can refer you to other services if you need them. Although everyone’s experience can be different, connecting with other people with haemophilia to share common experiences and tips can be valuable. Your HTC and your local haemophilia foundation can help with this.
Travel
Many people with haemophilia travel both within Australia and overseas. This can involve a little extra planning and discussion with your HTC. Check the locations and available times of HTCs in the places where you’re travelling before you set off, in case you run into trouble.
You may need to take treatment product with you. This may involve carrying it with you in a cooler bag and storing it in a fridge on your trip. If you’ll be away for a long time or going overseas, start planning with your HTC early.
Your HTC can also help with documents for customs and security. You may also wish to carry your ABDR (Australian Bleeding Disorders Registry) patient card with your diagnosis and treatment plan in your wallet or on your phone, set up your medical emergency info on your phone or to wear a medical alert bracelet or necklace.
Be informed and aware
Understanding your haemophilia and knowing how to manage it makes a big difference.
- Be aware of how your body responds to treatment and plan around it.
- Build a good relationship with your haemophilia team and don’t be afraid to ask questions.
- Keep up with the latest treatments and services.
More information
For more information, speak to your HTC.
Visit the Haemophilia Foundation Australia website for:
- the Gene and Emerging Therapies Hub
- contact details for Haemophilia Treatment Centres (HTCs), which are located in every state and territory.
References
Kitazawa T, Igawa T, Sampei Z, et al. A bispecific antibody to factors IXa and X restores factor VIII hemostatic activity in a hemophilia A model. Nature Medicine 2012;18:1570–1574. https://doi.org/10.1038/nm.2942
Srivastava A, Santagostino E, Dougall A, et al. WFH guidelines for the management of hemophilia, 3rd edition. Haemophilia. 2020: 26(Suppl 6): 1-158. Accessed 1 August 2022. Available from https://doi.org/10.1111/hae.14046.
Peyvandi F, Seidizadeh O, Mohsenian S, Garagiola I. Exploring nonreplacement therapies’ impact on hemophilia and other rare bleeding disorders. Research and Practice in Thrombosis and Haemostasis 2024;8(4):102434. https://doi.org/10.1016/j.rpth.2024.102434.
Reviewers:
HFA Gene and Emerging Therapies consumer review Group (individuals not named for privacy reasons).
Australian Haemophilia Centre Directors’ Organisation: Dr Sally Campbell, Dr Stephanie P’ng. ABDR Data Managers: Marina Goruppi, Venessa Mavrinac-Tiddy.
ANZ Haemophilia Psychosocial Group: Tanya Grueneweld, Jane Portnoy, Emma Wells.
Australian Haemophilia Nurses’ Group: Megan Walsh.
The video resources on this page are published by World Federation of Hemophilia (WFH) and are linked here with permission.
© 2023 World Federation of Hemophilia https://sdm.wfh.org/
This fact sheet has been funded by unrestricted education grants from CSL Behring and Sanofi. HFA does not promote any particular pharmaceutical product.