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FDA OKs First Gene Therapy for Beta-Thalassemia

— One-time treatment comes with a $2.8 million price tag

Ƶ MedicalToday
FDA APPROVED betibeglogene autotemcel (Zynteglo) over a computer rendering of deformed blood cells from thalassemia

Betibeglogene autotemcel (beti-cel; Zynteglo) won FDA approval Wednesday as the for the treatment of adult and pediatric patients with beta-thalassemia who require regular red blood cell (RBC) transfusions, the agency announced.

In June, the FDA's Cellular, Tissue, and Gene Therapies Advisory Committee gave beti-cel a unanimous endorsement, stating that it showed "outstanding efficacy" in two phase III trials in which 89% of patients given the cell-based product achieved transfusion independence. Results were seen across all ages and genotypes, including pediatric patients as young as age 4 years and those with the most severe genotypes.

The one-time gene therapy is administered as a single dose, with each dose customized using the patient's own bone marrow stem cells that are genetically modified to produce functional beta-globin.

"Today's approval is an important advance in the treatment of beta-thalassemia, particularly in individuals who require ongoing red blood cell transfusions," said Peter Marks, MD, PhD, director of the FDA Center for Biologics Evaluation and Research, in a statement. "Given the potential health complications associated with this serious disease, this action highlights the FDA's continued commitment to supporting development of innovative therapies for patients who have limited treatment options."

Beti-cel therapy has a , with developer Bluebird Bio setting the wholesale acquisition cost in the U.S. at $2.8 million "in recognition of its robust and sustained clinical benefit demonstrated in clinical studies and its potential to alleviate a lifetime of health care costs associated with regular RBC transfusions and iron management," the company stated. The developer noted that the current lifetime cost of medical care for a U.S. patient with transfusion-dependent beta-thalassemia can reach up to $6.4 million.

According to Bluebird Bio, beti-cel will only be available at qualified treatment centers due to the "complex nature" of gene therapy. These centers will receive specialized training in administering the therapy, and will be "carefully selected based on their expertise in relevant areas such as stem cell transplantation, cell and gene therapy, and beta-thalassemia."

The most common adverse events associated with beti-cel are reduced platelet and other blood cell levels, as well as mucositis, febrile neutropenia, vomiting, fever, alopecia, nosebleed, abdominal pain, musculoskeletal pain, cough, headache, diarrhea, rash, constipation, nausea, decreased appetite, pigmentation disorder, and pruritus.

The FDA noted that there is a potential risk of blood cancer associated with the treatment, although no cases were seen in studies of beti-cel. Patients who receive the therapy should be monitored for at least 15 years for any evidence of cancer, according to the agency, along with monitoring for thrombocytopenia and bleeding.

"Transfusion-dependent beta-thalassemia is associated with an intense treatment burden and significant health risks related to regular red blood transfusions and iron management," said Alexis Thompson, MD, MPH, chief of the Division of Hematology at Children's Hospital of Philadelphia, in a press release from Bluebird Bio. "As a clinician and an investigator in the Zynteglo clinical development program, I celebrate the therapeutic potential of this treatment for patients and its implications for the field of gene therapy, all made possible through the incredible courage of patients and families who participated in the clinical trials."

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    Mike Bassett is a staff writer focusing on oncology and hematology. He is based in Massachusetts.