The Food and Drug Administrations rejection of a gene therapy for hemophilia A on Wednesday surprised many hematology researchers and Wall Street watchers who expected speedy approval for the one-time treatment to end the inherited bleeding disorder.
For one family in Indianapolis active in the hemophilia patient community, the decision was disappointing, but also appreciated.
Its a sad day because for a lot of people, they were ready to go, Michelle Rice, whose two sons have severe forms of hemophilia A, told STAT. But its also a good day, said Rice, who has a mild case of the disease and serves as chief external affairs officer for the National Hemophilia Foundation, because I think this community has fought long and hard for safety to be a priority.
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Hemophilia A is a genetic disorder in which the body fails to produce a protein called Factor VIII that is crucial for blood clotting. It affects about 20,000 people in the U.S., almost all men. The bleeding episodes and joint damage it causes are kept under control by frequent infusions costing about $300,000 per year.
BioMarins gene therapy, called Roctavian, is designed to fix that inherited defect, but the therapys impact on Factor VIII levels seems to wane over time. A year after treatment, patients in BioMarins clinical trial had Factor VIII levels of 64.3 international units per deciliter on average. After two years, that number fell by more than half. Four years after treatment, the average was 24.2 IU/dL, a 63% decline from the first year.
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The FDA has asked for two more years of data to better establish the durability of the gene therapy. That means the one-time treatment, if approved, will be delayed until at least 2022.
Roctavian is one of three gene therapies for hemophilia A now being developed. Roche, which acquired Spark Therapeutics gene therapy program when it bought the biotech earlier this year, and the partnership of Pfizer and Sangamo Therapeutics are at work on similar one-time therapies. Each is a year or more away from filing for FDA approval.
Len Valentino, CEO of the National Hemophilia Foundation, applauded the FDAs push for more durability data. He is a hematologist and former vice president, strategy lead in hematology, at Spark.
I think its good for the patient community because we need to protect our patients at all costs, he said. This is a community thats been through a tremendous amount of grief in the past with first HIV and AIDS and then hepatitis C. So I think protecting our community is of the utmost importance. And at this point, theres just too many unknowns that we dont understand the answers to.
In the 1970s and 1980s, about half of all people with hemophilia became infected with HIV after being transfused with contaminated blood products. Many patients with severe hemophilia developed AIDS, and thousands died. Infection with hepatitis C was also common when patients relied on infusions of clotting factors from human plasma, before the availability of recombinant factor VIII and IX made their treatments safer.
In the 80s, our population was decimated by HIV. Then in the late 80s, early 90s, a lot of them got hepatitis C, Rice said. My older son was one of them.
The more than a dozen products now available are safer, she said, and the treatments have made a huge difference for her older son, now 30, preventing the bleeding episodes that used to mean he was in the hospital every 7 to 10 days. Her younger son, who is 25, has fared better. Spontaneous bleeds are rare and prophylactic infusions several times a week have become as routine as brushing your teeth, Rice said.
Right now, were comfortable with where we are, she said. Were comfortable with the way our bodies feel.
Valentino called current therapies to treat hemophilia good, safe, and effective. At this point, the unmet medical need for hemophilia A is not great because I think the standard of care is quite good at this point.
There are two other sticking points for Rice and her sons, who arent pinning their hopes on any gene therapy: It doesnt change the genes you pass down to your children. And she wonders how long its benefits will last.
Everybody wants to see gene therapy. I can tell you that from the time my oldest was born, I was hearing gene therapy is going to be here in 10 years, she said. Its not that people in the community are not excited about it. I think they very much are excited about it. I feel like were probably closer than weve ever been getting here. And my kids have said were not going to rule it out forever.
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Wary hemophilia patients are willing to wait longer for a safe gene therapy - STAT
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