The following FAQs may be helpful in clarifying what gene therapy is. Most gene therapy strategies use a vector, such as modified virus, to attempt to deliver a good copy of a gene to a cell that contains a defective gene. Scientists hope that the transferred gene will then restore the normal functions. For people with hemophilia, this means that clotting factor genes inserted into the body would enable normal clotting factor proteins to be produced for the first time. Yes, but rarely.
Gene therapy is a very young science that has been used in patients for only about ten years.
Thousands of patients with cancer and infectious diseases such as AIDS have been treated but have not been cured yet. Some non-human animals have been cured of diseases using gene therapy, including dogs with hemophilia. Their immune systems have been restored. The first gene therapy trial for hemophilia involves hemophilia A and a therapy developed by the Chiron Corporation, a California company. The gene is carried in a mouse retroviral vector, a virus that normally infects mice.