The most common adverse reactions include reduced platelet and other blood cell levels, as well as mucositis, febrile neutropenia, vomiting, pyrexia (fever), alopecia (hair loss), epistaxis (nosebleed), abdominal pain, musculoskeletal pain, cough, headache, diarrhea, rash, constipation, nausea, decreased appetite, pigmentation disorder and pruritus (itch).[5]
It was approved for medical use in the European Union in May 2019,[2] and in the United States in August 2022.[5]
Betibeglogene autotemcel is made individually for each recipient out of stem cells collected from their blood, and must only be given to the recipient for whom it is made.[2] It is given as an autologous intravenous infusion and the dose depends on the recipient's body weight.[3][2]
To make betibeglogene autotemcel, the stem cells taken from the recipient's blood are modified by a virus that carries working copies of the beta globin gene into the cells.[2] When these modified cells are given back to the recipient, they are transported in the bloodstream to the bone marrow where they start to make healthy red blood cells that produce beta globin.[2] The effects of betibeglogene autotemcel are expected to last for the recipient's lifetime.[2]
Mechanism of action
Beta thalassemia is caused by mutations to or deletions of the HBB gene leading to reduced or absent synthesis of the beta chains of hemoglobin that result in variable outcomes ranging from severe anemia to clinically asymptomatic individuals.[8] LentiGlobin BB305 is a lentiviral vector which inserts a functioning version of the HBB gene into a recipient's blood-producing hematopoietic stem cells (HSC) ex vivo. The resulting engineered HSCs are then reintroduced to the recipient.[9][10]
History
In early clinical trials several participants with beta thalassemia, who usually require frequent blood transfusions to treat their disease, were able to forgo blood transfusions for extended periods of time.[11][12][13] In 2018, results from phase 1-2 trials suggested that of 22 participants receiving Lentiglobin gene therapy, 15 were able to stop or reduce regular blood transfusions.[14][15]
The safety and effectiveness of betibeglogene autotemcel were established in two multicenter clinical studies that included adult and pediatric participants with beta-thalassemia requiring regular transfusions.[5] Effectiveness was established based on achievement of transfusion independence, which is attained when the participant maintains a predetermined level of hemoglobin without needing any red blood cell transfusions for at least 12 months. Of 41 participants receiving betibeglogene autotemcel, 89% achieved transfusion independence.[5]
Society and culture
Legal status
It was approved for medical use in the European Union in May 2019,[2] and in the United States in August 2022.[5] On 24 March 2022, the European Commission withdrew the marketing authorisation for Zynteglo at the request of bluebird bio (Netherlands) B.V, for commercial reasons.[20]
Economics
Bluebird bio charges $2.8 million in the United States for a treatment of Zynteglo.[21][22]
^ abcdefghijklm"Zynteglo EPAR". European Medicines Agency (EMA). 25 March 2019. Archived from the original on 16 August 2019. Retrieved 16 August 2019. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.
^ abClinical trial number NCT02140554 for "A Phase 1/2 Study Evaluating Gene Therapy by Transplantation of Autologous CD34+ Stem Cells Transduced Ex Vivo With the LentiGlobin BB305 Lentiviral Vector in Subjects With Severe Sickle Cell Disease" at ClinicalTrials.gov