Experimental Beta Thalassemia Drug Gains Temporary Short-Term Approval in Europe

According to a publication from BNN Bloomberg, regulatory authorities in the European Commission recently granted conditional marketing authorization (CMA) to Zynteglo. Zynteglo is a gene therapy designed to treat beta thalassemia, a rare blood disorder.

Bluebird Bio Inc., Zynteglo’s proprietor, has not yet specified a price for the treatment. Historically, gene therapies for rare diseases have sold for over a million dollars. Zolgensma, a gene therapy to treat spinal muscular atrophy marketed by Novartis, costs $2.1 million a pop.

About Beta Thalassemia

Beta thalassemia is a genetic condition characterized by diminished hemoglobin production. Hemoglobin is a ferrous protein found in red blood cells. Oxygen readily attaches to hemoglobin, which is why red blood cells are able to effectively circulate the oxygen we breathe.

As logic would follow, low hemoglobin levels result in worse oxygen distribution throughout the body — contributing to a variety of potential health problems. People with beta thalassemia may additionally have a low red blood cell count (anemia), which can further exaggerate oxygen shortages and contribute to more serious complications. Despite some experiencing a reduction in red cell count, beta thalassemia patients have an increased risk of abnormal clot formation (thrombosis).

Beta thalassemia is caused by a mutation to the gene HBB, normally responsible for coding the production of beta-globin, one of the two types of protein that make up larger hemoglobin molecules. Mutations to HBB can disrupt beta-globin production, and, subsequently, hemoglobin levels.

Individual cases of beta thalassemia can range widely in their severity. Depending on their severity, cases are classified into thalassemia major and thalassemia intermedia. Thalassemia major is much more severe, and usually presents symptoms in children before their second birthday. Thalassemia intermedia may not present symptoms until later in life.

Patients with beta thalassemia are often dependent on regular blood transfusions, which can be physically taxing over a lifetime of chronic illness.

Zynteglo granted Conditional Marketing Authorization in Europe

Conditional marketing authorizations (CMAs) are granted by the European Medicines Agency (EMA), which is sort of like Europe’s version of the Food and Drug Administration. Conditional marketing authorizations are meant to help patients with otherwise unmet treatment needs access therapies still being researched. A study showed that it took an average of four years for a drug to progress from conditional marketing authorization to full market authorization.

CMAs are awarded on a short-term basis, active for only one year at a time. Recipients of a CMA are required to conduct further research to move their product closer to a full and lasting approval.

In clinical studies, Zynteglo showed impressive promise at decreasing transfusion dependence in beta thalassemia patients who previously had required regular transfusions. In one study, 75% of responding patients achieved transfusion independence — meaning they had gone a full year since their last blood transfusion. In another study, 80% achieved transfusion independence. It’s important to note that these high percentages may in part reflect just how minuscule the study groups are — the 75% and 80% in these studies represent a total of 11 individuals out of a total 15 participating.

The initial numbers look promising, but the EMA and European Commission are well within reason to require additional study before permanently approving Zynteglo. Nonetheless, the news will doubtlessly come as welcome to many in the European rare disease community.


Genetic therapies for rare conditions are often incredibly expensive. However, they may be cheaper over time than less individually costly, but recurring expenses like drug therapies. How do you think this will impact the patient? Share your thoughts with Patient Worthy!

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