Recently, Pfizer’s Dr. Ian Winburn sat down with Europabio for an interview in honor of World Hemophilia Day, which just occurred on April 17. In his discussion, Dr. Winburn covered the disorder’s subsets, potential treatments, and Pfizer’s role in rare disease research.
Hemophilia is a rare genetic bleeding disorder in which blood does not clot normally. Typically, people have around 12 clotting factors (special proteins) in the body. When people bleed, the blood cells clump together to form clots. This closes the cut and stops further bleeding. But with hemophilia, people may bleed more or for longer. Genes for hemophilia are located on the X chromosome, making men making men more likely to experience low levels of clotting factor, while women, who have 2 X chromosomes, may have higher levels of factor as the unmutated allele in their second X chromosome may mitigate the effect.
According to Dr. Winburn, many members of royal families in the 19th and 20th centuries had hemophilia. Thus, it is historically known as the “royal disease.”
Symptoms include large and deep bruises, joint pain, joint inflammation, excessive and prolonged bleeding from injuries or medical procedures, bloody stool, and random bleeding. If you experience severe “emergency” symptoms, such as vomiting, fatigue, double vision, or sudden pain or bleeding, please see a doctor immediately. Learn more about hemophilia here.
Also known as classic hemophilia, people with hemophilia A have a deficiency of clotting factor VIII. This form of the disorder is more common than hemophilia B. Sixty percent of people with this type of disorder will experience nose bleeds, bruising, bleeding in the digestive and urinary tract, and bleeding and inflammation in joints. Read more about hemophilia A here.
Also known as Christmas disease, people with hemophilia B have a deficiency of clotting factor IX. In rare cases, people experience more bleeding episodes as children but less as they age. Symptoms include spontaneous bleeding, bruising, nosebleeds, and urinary and gastrointestinal bleeding. Infants with Christmas disease are often diagnosed near the time of birth. Read more about hemophilia B here.
Dr. Ian Winburn: A Discussion
Dr. Winburn works within the Rare Disease Business Unit at Pfizer. This unit currently focuses on metabolic disorders, endocrinology, and hemophilia. Pfizer has been creating recombinant clotting factor replacement medicines for more than 20 years.
However, Pfizer is now switching their focus to gene therapies. Gene therapies are medications that deliver a specific gene to the body. Generally, this gene targets the missing, degenerated, or non-functional protein that causes the rare disease or disorder. Gene therapy can be personalized for varied patients and conditions.
In terms of Pfizer, the company is exploring a humanized monoclonal antibody. A humanized monoclonal antibody is one which combines an animal (mouse) antibody with a human antibody. While one targets the antigen (which causes the disease), the human antibody keeps the immune system from attacking. So, Pfizer is looking to potentially develop a “non-factor” replacement therapy using this antibody that will help the body create clots.
While treatments for hemophilia do already exist, Pfizer wants to mitigate remaining or chronic symptoms like spontaneous or excessive bleeding. Additionally, current treatments are lengthy and exhausting. Through gene therapy, patients will experience a singular treatment that will reduce hospitalizations and additional care while maximizing quality of life.