Using gene therapy for hemophilia treatment is in many ways a promising option, but it also has some drawbacks. On the pro side, hemophilia is an ideal genetic disorder to treat in this fashion, as it occurs due to a single genetic defect. This type of treatment can be considered successful even if it results in only minimal increases in clotting factors in the blood, as this is still an enormous benefit to patients. On the con side, results in clinical trials with human test subjects have been inconsistent. There is also the risk that the patient's body will develop antibodies to the viral vectors used to deliver the genetic material to the cells.
One of the main pros of gene therapy for hemophilia is the way the disease occurs. In terms of a genetic disorder, it is fairly simple, caused by one known genetic defect that limits the body's ability to generate clotting factors in the blood. Unlike other genetic diseases that may involve numerous defects, hemophilia is relatively easy to target for gene therapy.
Another reason that gene therapy for hemophilia is so promising is that even minimal success from the procedure can mean significant improvement in quality of life for patients. In some tests, the therapy has led to a slight increase in clotting factors in the blood, well below normal, but the time it took for the subject's blood to clot decreased significantly. People who see such improvements may be able to go for long periods of time without supplemental infusions of clotting factor.
Gene therapy for hemophilia is not all positive, however, as the results of the treatment are rather inconsistent. Many studies done on animals have been done, often with good results, but that has not translated to similar results in human beings. Different methods of delivery via different types of viral vectors, as well as varying doses, have led to mixed results, with a consistently successful treatment method still proving elusive.
The method of treatment is another con when it comes to gene therapy for hemophilia. In order to get the genetic material to the cells, it is necessary to attach it to viruses, which are then injected into the body so they can invade those cells. In some cases, this can trigger an immune response in the patient. His or her body may then produce antibodies which destroy the viruses, stopping the treatment from occurring.