A little more than half a century ago, the only treatment available for hemophilia was to give patients blood transfusions during or after bleeding events. It’s only been since the mid-1990s that we’ve been able to help prevent bleeding events and not just react to them.
Today, our patients at the North Texas Comprehensive Hemophilia Treatment Center – the only adult-focused hemophilia treatment center in Texas – have access to treatments that patients are describing as life changing.
Hemophilia is a lifelong, rare bleeding disorder that approximately 400 babies are born with each year in the U.S. Hemophilia is caused by a genetic mutation that impairs the function of clotting factors VIII or IX, which makes the blood clot poorly or not at all. Patients typically are diagnosed between 1 month and 3 years of age, and about 66% have a family history of the disorder.
For patients with hemophilia, scraping a knee or bruising a hand while doing home repairs can cause serious external or internal bleeding that requires a blood transfusion.
Until recently, treatments have focused on replacing a patient’s missing clotting factor through IV therapy directly into a vein. While most patients with hemophilia can learn to administer their own IV therapy, these treatments can be time-consuming and difficult to complete for patients with poor vein access or young people living on their own for the first time.
But after more than three decades of limited treatment options, several new and improved therapies have become available in the last few years, such as single-injection therapies with no IV required. And with advanced therapies coming down the pike, the future is bright for patients living with hemophilia.
Swapping IV infusions for a single injection
In 2017, the U.S. Food and Drug Administration (FDA) approved a new single-injection drug called emicizumab (brand name Hemlibra), to prevent or reduce the frequency of bleeding episodes. Normally, when a clotting factor is missing, the “cascade” – the clotting formation reaction – stops. Emicizumab bridges the gap by replacing the function of factor VIII instead of replacing the clotting factor itself, allowing the cascade to continue and a clot to form.
Instead of having to find a vein for multiple IV infusions a week, emicizumab is given through an injection under the skin once a week, once every two weeks, or once a month.
This has made a huge difference in terms of the burden of the treatment on our patients. In fact, some patients on emicizumab have not needed an extra factor VIII infusion for several years. The drug works only for patients with factor VIII deficiency (hemophilia A), which is the most common type of hemophilia.
However, we expect a new once-a-month subcutaneous hemophilia injection, Fitusiran, to be available soon for patients with hemophilia A and those who are missing clotting factor IX (hemophilia B). This novel drug, which is in phase three clinical trials, targets and represses antithrombin, a protein produced by the liver that prevents clotting. Repressing antithrombin promotes the generation of thrombin, an enzyme that leads to clot formation.
Gene therapy for hemophilia
While several types of gene therapies are being studied in clinical trials, gene transfer via adeno-associated virus (AAV) vector-based gene therapy is furthest along the pipeline.
Comprehensive Hemophilia Treatment Center at UTSW
We have the only adult-focused hemophilia treatment center in Texas. Learn more about the services provided by our team.
Adeno-associated viruses are benign viruses that infect the liver, where clotting proteins are made, without causing health issues. AAV vector-based gene therapy uses a modified virus to deliver functional copies of factor VIII or factor IX genes to cells in the liver, empowering the body to make its own clotting factor. However, there are immune-related side effects to consider such as liver inflammation and the possibility of forming lesions or tumors.
Early trial results have been promising – patients have shown clotting factor levels within a normal range for approximately three years before their levels begin to decline. The FDA has asked for longer-term data to determine how long the factor levels hold steady and whether they eventually plateau or continue to decrease.
UT Southwestern enrolled patients in one of the early AAV gene therapy trials, and they are doing great. One has only had to infuse factor IX once or twice in the years since the gene therapy. This is in contrast to having to do it once a week before the trial. It’s been life-changing for them. Search for ongoing hemophilia clinical trials.
Nationally, clinical trials are ongoing using gene editing, which uses tools such as CRISPR/Cas9 to change the body’s original DNA and improve function. It has been proven effective for hemophilia A in preclinical studies, and we are eager to join future trials for this technology.
The role of physical therapy for hemophilia
As a comprehensive adult hemophilia treatment center, we offer patients with hemophilia care options that are not widely available. For example, we emphasize the benefits of specialized physical therapy, which can help:
- Build strong muscles to protect the joints and reduce the risk of bleeds
- Increase strength and flexibility, leading to fewer accidents
- Restore damaged joints or muscles after a bleed
Physical therapists who specialize in hemophilia can conduct a musculoskeletal ultrasound to see in real time whether there is bleeding in the joints. Early detection is key to avoiding serious damage or a prolonged hospital stay.
Because hemophilia is a lifelong disease, we get to know our patients pretty well over the years. As much as we enjoy them, our goal is to see them less and less because that means they are healthy – and potentially one day in the future, cured. Until that day, we continue to push the boundaries of research, seeking more opportunities to help patients live full, active lives.
To discuss hemophilia care with a specialist, call 214-648-1939 or email the North Texas Comprehensive Hemophilia Treatment Center.