By Lauren Thayer from In The Cloud Copy
Hemophilia is a medical condition in which a person’s blood clotting ability is severely reduced. This inability to properly clot leads to severe bleeding even from a seemingly minor injury, which can ultimately lead to serious injury or death. There are three types of hemophilia. Hemophilia A is caused by the absence of blood clotting factor VIII. Hemophilia B is caused by a deficiency of factor IX, and Hemophilia C is caused by missing or defective factor XI. Hemophilia A and B are the most commonly seen types.
Standard treatment for Hemophilia A is aimed at replacing the missing factor VIII for patients on a prophylactic basis to hopefully prevent spontaneous bleeding episodes. Unfortunately, many patients develop neutralizing antibodies to the artificial factor VIII, making these treatments no longer viable for the patient eventually.
Hemophilia B is treated in a similar fashion. Patients receive infusions of clotting factor IX to help replace the clotting factor that is naturally absent or low in the patient’s blood.
While standard treatments seem sufficient in the short-term, if the patient develops antibodies, the treatment is rendered useless. The development of gene therapy as a treatment for hemophilia is in the works and showing promising results.
Joana Carvalho, PhD, has studied these therapies and their recent results. AMT-180, a gene therapy developed by uniQure, uses an adeno-associated virus (AAV) vector called AAV5 to deliver a modified F9 gene independently of factor VIII. This works to promote blood clotting in the affected individual.
Early data showed that the administration of AMT-180 into animal models of hemophilia A led to appropriate blood clotting activity. Further, the therapy was not associated with any increase in levels of coagulation markers in the blood, which could indicate an increased formation of blood clots.
Additionally, researchers at uniQure have shown that a single dose of AMT-060, uniQure’s gene therapy for treatment of hemophilia B, when given to mice very early in life, was sufficient to maintain activity of modified factor IX for up to 18 months.
A commonly asked question with gene therapy is how often a patient would need re-treatment. The data shows almost no loss of genetically modified cells after their administration of AAV5-hFIX during the mice’s lifespan, suggesting that the artificial genetic material was in fact transferred to the daughter cells during cell division. This finding shows the promising nature of this gene therapy for hemophilia patients.
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