The European Commission granted conditional marketing approval to bluebird bio Inc.'s gene therapy Zynteglo to treat a rare inherited blood condition in patients 12 years and older.
Zynteglo is now approved to treat transfusion-dependent beta-thalassemia, or TDT, in patients who do not have a β0/β0 genotype, for whom blood stem cell transplantation is appropriate but a matching donor is not available.
TDT is a severe genetic disease caused by mutations in the beta-globin gene that result in reduced or absent hemoglobin. People with the condition have to continuously get blood transfusions to maintain adequate hemoglobin levels in order to survive, but these transfusions carry the risk of progressive multi-organ damage due to unavoidable iron overload.
Zynteglo is a one-time gene therapy that adds functional copies of a modified form of the beta-globin gene into a patient's own blood stem cells — immature cells that can develop into all types of blood cells — and has the potential to allow patients to become transfusion independent.
The Cambridge, Mass.-based company's gene therapy was reviewed as part of the European Medicines Agency's Priority Medicines and Adaptive Pathways programs, which support medicines that may offer a major therapeutic advantage over existing treatments, or benefit patients without treatment options.
The conditional marketing authorization — valid in all 28 member states of the EU as well as Iceland, Liechtenstein and Norway — is based on data from two phase 1/2, two ongoing phase 3 studies and a long-term follow-up study.
In the phase 1/2 study, named HGB-205, 75% of patients who do not have a β0/β0 genotype achieved transfusion independence, while 80% of such patients saw a similar response in the phase 1/2 study called Northstar. In addition, 80% of patients achieved transfusion independence in the phase 3 Northstar-2 study.
Zynteglo has received an orphan medicinal product designation from the European Commission to treat beta-thalassemia intermedia and major, which includes TDT. The U.S. Food and Drug Administration has granted the gene therapy orphan-drug status and a breakthrough-therapy designation for treating TDT.