Hemophilia is a rare, inherited bleeding disorder in which the blood does not clot normally. According to the U.S. Centers for Disease Control & Prevention, these patients bleed for a longer time than other people following an injury. The also can bleed internally.
Oncologist Brian Adler, MD, treats hemophilia patients at his Brookwood Baptist clinic. "Hemophilia A is the most common and affects blood clotting factor 8. It occurs in one to 5,000 males," he says. "Hemophilia B is less common and occurs in one to 25,000 males. It results from an affected factor 9."
Adler points out that while he treats the disorder, most of the hemophilia patients in Birmingham and the State of Alabama are treated at the Hemophilia Treatment Center through Children's Rehabilitation Services.
Christina Bemrich-Stolz, MD, MSPH
Christina Bemrich-Stolz, MD, MSPH, is the pediatric oncologist at the Birmingham treatment center and is also an assistant professor in the UAB Division of Pediatric Hematology and Oncology. She says that while many of these patients are diagnosed with hemophilia at birth, others may not be identified until later in life.
"About 70 percent of patients have a family history of hemophilia, but the other 30 percent have a new mutation that isn't present in their family history," Stolz says. "For those with no family history, we often discover the disorder when baby boys are circumcised and the bleeding is not well controlled, which prompts an evaluation."
Hemophilia is most frequently found in males. "It's a factor deficiency disorder," Stolz says. "The factor 8 and factor 9 genes are on the X chromosome, so if you are a female, you have two X chromosomes. If there is a mutated factor gene on one chromosome, the normal X chromosome supports it and makes up for the factor that is missing from the mutated chromosome.
"Since a boy has only one X chromosome, if he receives a mutated X chromosome from his mother, he will have hemophilia. However, 30 percent of the time, it will be a new mutation that wasn't inherited and we would have no reason to suspect hemophilia unless there is unexpected bleeding."
Because bleeding is the main issue with hemophilia, most of the complications these patients experience are because of the bleeding.
"Bleeding can be life threatening," Stolz says. "Before we had good treatment options, patients would have frequent and significant joint bleeds. Repeated bleeding in a joint will result in damage to the joint, and many patients would have difficulty walking or be in wheelchairs. We now know that we can prevent some of the bleeding by giving factor prophylaxis to these young men. Studies have shown that it decreases joint bleeding and disability in those patients."
Adler praises the factor products that are available today, especially the recombinant products designed to raise factor 8 levels which decreases joint bleeding. He remembers the 1980s when many young men with hemophilia contracted HIV through donor plasma.
"Because of the purification problem back then, there was no way to screen the donor blood," he says. "Unfortunately, a lot of hemophilia patients developed HIV and died in the early 80s and 90s. Now the purification process is extremely good, and I don't think we've had a transmission of HIV in decades. Thanks to the recombinant products, the safety is excellent now."
A recent international randomized study looked at the development of inhibitors in patients that received plasma-derived factor (from donated plasma) as opposed to recombinant factor. Improved donor screening and viral inactivation processes have made plasma much safer that it was in the 1980s. Inhibitors, or antibodies against factor 8, are a serious medical problem that can occur when a person with hemophilia has an immune response to treatment with clotting factor concentrates. Sometimes a person's immune system reacts to proteins in factor concentrates as if they were harmful substances because the body hasn't seen them before. In that case, the body prevents the factor concentrate from fixing the bleeding problem.
"The studies showed that the risk of an inhibitor is less in patients who received plasma-derived factor as opposed to recombinant factor," Stolz says. "If a patient develops an inhibitor to their factor, they no longer respond to infused factor, and we have to use different medications to treat them if they are bleeding. These medications aren't as effective as factor and the patients receiving the medicine have more bleeding than people without an inhibitor.
"So we now know that patients who receive the recombinant factor are more at risk of developing an inhibitor than those who receive plasma-derived factor. However, we have been using these recombinant products for years, so we know it is safe. If families are uncomfortable using the plasma drive products, this is another option for them."
In the past few years, a new product for factor 9 deficiency has been approved and is longer lasting than others. That means that some patients who usually do twice-a-week factor prophylaxis now can extend treatments to every two weeks.
"In October, another new product called emicizumab was approved, and I am offering it to my patients with factor 8 deficiency," Stolz says. "It is a bi-specific antibody that acts in a similar way to factor 8. It is not factor 8 itself. It just does the same work as factor 8. The advantage of emicizumab is that it can be administered with a subcutaneous shot that is given once a week."
There also are three new subcutaneous injection products currently undergoing trials for factor 8 or 9 deficiency. "There are phase two studies underway for patients with either factor 8 and 9, so we are going to have a lot of options for these patients soon," Stolz says. "I tell the parents of new patients to keep seeing me, because we soon will have a lot of treatment options."