Clinical trials of gene therapy for hemophiliacs are about to begin soon, reports New Scientist.
The aim of the new therapy is to cure adult research participants of type B haemophilia. Patients with a deficiency of an enzyme called factor IX develop a bleeding disorder – they must avoid any activity that could be traumatic, and even spontaneously bleed internal hemorrhages.
The disease is caused by a mutation in the gene that causes the liver to produce factor IX. The missing factor can be administered to patients, but there are complications such as joint pain or an increased risk of other diseases.
The treatment currently under trial uses an enzyme called zinc finger nuclease (ZFN), which can replace the abnormal gene with its correct version. ZFN is the work of Michael Holmes and Thomas Wechsler of the Californian biopharmaceutical company Sangamo.
To introduce the enzyme into cells, scientists used a harmless virus. Studies in mice and monkeys deficient in factor IX have successfully introduced the correct gene into liver cells. By being adjacent to a gene that regulates the action of other genes, factor IX production was in full swing and the blood of mice and monkeys regained its ability to clot.
If the adult research is successful, Sangamo wants to apply the method to children. The earlier the intervention, the less damage the hemophilia can do to the body.
The method can also be used to treat other similar diseases with a genetic background, say its authors. (PAP)