Bluebird bio has announced that its gene therapy Zynteglo (autologous CD34+ cells encoding βA-T87Q-globin gene) has been granted conditional marketing authorisation in Europe for certain patients 12 years and older with transfusion-dependent β-thalassaemia (TDT).

The authorisation for the inherited blood disorder marks bluebird’s first ever drug approval, and is based on the completed Phase I/II HGB-205 study and Phase 1/2 Northstar (HGB-204) study as well as available data from the ongoing Phase III Northstar-2 (HGB-207) and Northstar-3 (HGB-212) studies.

The authorisation for the indication of TDT patients who do not have a β0/β0 genotype, for whom haematopoietic stem cell transplantation is appropriate but a human leukocyte antigen (HLA)-matched related HSC donor is not available.

In addition to Priority Medicines (PRIME) designation, the therapy received an Orphan Medicinal Product designation from the EU for the treatment of β-thalassaemia intermedia and major, which includes TDT.

“Using an autologous transplantation approach, this treatment offers clinicians the first gene therapy to tackle the underlying genetic cause in a subset of people with transfusion-dependent β-thalassaemia. It potentially eliminates or reduces the need for red blood cell (RBC) transfusions, using the patient’s own haematopoietic stem cells (HSCs),” said Professor John Porter, Professor of Haematology and Consultant Haematologist at the University College London Hospitals.

He continued, “This is a significant development, since previously the only way to address the genetic cause was through an allogeneic haematopoietic stem cell transplant, which is restricted by donor availability, carries serious risks particularly in adults, and is only available to paediatric patients in the UK.  As a result, most patients currently require lifelong red blood cell transfusions and iron chelation therapy to manage iron overload.”

TDT is a severe genetic condition caused by mutations in the β-globin gene that result in reduced or absent haemoglobin. In order to survive, people with TDT maintain haemoglobin levels through life-long chronic blood transfusions which carry the risk of progressive multi-organ damage due to unavoidable iron overload.