A century ago, the average life expectancy for someone suffering from the bleeding disorder hemophilia was just 13 years1. Even into the 1960s, a hemophilia patient might expect to only live to 30. Today, a child with the same disease can expect to live a full and active life.
The advancements made in hemophilia treatments over the last 50 years have completely transformed the lives of sufferers. They have turned what was a hereditary death sentence into a disease that can be effectively managed at home.
And what of tomorrow? Cutting-edge genetic techniques could have the potential to go one step further, to offer a single treatment to what has till now been a lifelong burden.
Hemophilia is a genetic disease in which you do not produce the necessary blood-clotting factors, or proteins.2 When you cut yourself, there is a cascade of these factors, a series of reactions that tell your blood when to clot. So, like dominoes, if you are missing one of these factors, the cascade doesn’t happen and your blood doesn’t clot properly.
For much of the 20th century, scientists could not produce these factors so instead patients required large transfusions of blood plasma from donors.
In 1965, Dr. Judith Graham Pool developed a technique called cryoprecipitate3, where frozen blood plasma is thawed and the factor VIII-rich precipitate left is collected and stored. This substantially reduced the volume of blood required and through the 1970s and '80s additional techniques were developed to further concentrate the factor into ever smaller amounts. So much so that self-infuse factor products, such as bottles of freeze-dried concentrate, were developed that could be stored and used at home.
These treatments, however, were typically ‘on-demand’, responding to a bleed. The advent of recombinant clotting factors in the 1990s4 changed all this. The successful cloning of the factor VIII gene meant the protein could be synthesized and produced on its own, meaning patients could inject it as a prophylaxis, that is as a preventative treatment.
The blood clotting process is like a domino effect - we require a chain of clotting factors to stop a bleed.
Living with hemophilia today
So, what does this mean for someone suffering from hemophilia today? When people think of hemophilia, they often picture someone having to live a very careful, low risk life. That is far from the case. Living with hemophilia doesn’t mean living in bubble wrap, in constant fear of cutting yourself. Sufferers can live normal healthy lives, involving themselves in more activities.
“Whenever you cut yourself or you get hit in say the leg or the arm, that's a muscle bleed or a skin bleed, that stuff heals. A lot of people think every bleed is a problem when really it's not. The internal bleeds are the ones that can cause the long-lasting damage,” says Dakota J. Rosenfelt, PharmD, CEO of HemoTool and patient advocate speaker.
“Making sure that you're healthy and active actually plays lots of important roles. You want to make sure that your joints are cushioned. The more muscle you have around your joints, the better it is. It also increases your vascularity. It helps your vascularity to where it's easier to do your treatments.”
Hemophilia patients such as Dakota will typically inject their recombinant treatment a few times a week to make sure they have enough factor VIII in their blood should they have an accident.
The process of gene editing, where a piece of DNA is cut and replaced with the correct gene.
A future free from injections?
What if frequent injections could be significantly reduced? What if rather than the protein, the correct gene itself could be introduced?
The latest pioneering genetic techniques may hold the key. Among the approaches being developed are vector-based gene therapy and gene editing5.
Vector-based gene therapy, such as that being developed by Ultragenyx and Bayer, sees an intact factor VIII gene introduced via a non-pathogenic viral ‘envelope’ into target cells in the liver. The gene would exist alongside its defective counterpart and enable the patient’s liver to produce factor VIII as and when it is required.
With gene editing, researchers are looking to replace the defective DNA sequence in the patient’s genome with an intact new segment. To do so, they use gene scissors, a method for precisely cutting DNA. Pioneering gene editing company Casebia Therapeutics, for example, is using CRISPR-Cas9 to essentially cut the DNA at a defined location and insert the correct factor VIII gene.
These techniques hold huge promise, the potential to cure a patient permanently through a one-time treatment. But there remains some way to go before this becomes reality. In the meantime, the remarkable advances of the last 50 years are helping hemophilia sufferers live happy healthy lives every day.
- History of Bleeding Disorders, National Hemophilia Foundation, https://www.hemophilia.org/Bleeding-Disorders/History-of-Bleeding-Disor…
- Fast Facts: About Bleeding Disorders, National Hemophilia Foundation, https://www.hemophilia.org/About-Us/Fast-Facts
- Nascimento, B., et al. Cryoprecipitate therapy, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4627369/
- Hemophilia: From Plasma to Recombinant Factors, American Society of Hematology, https://www.hematology.org/About/History/50-Years/1524.aspx
- New Therapeutic Approaches for Hereditary Diseases, Bayer Research Magazine, https://www.research.bayer.com/en/hemophilia-new-therapeutic-approaches…