Bluebird bio Cleared to Resume Clinical Studies of Two Gene Therapies
Bluebird bio, a gene therapy company with manufacturing facilities in Durham, is resuming clinical trials of potential therapies for two inherited blood disorders after clearance from the U.S. Food and Drug Administration.
The FDA has lifted the holds it had placed on two clinical studies of a gene therapy for sickle cell disease and two clinical studies of a gene therapy for transfusion-dependent beta-thalassemia. The holds were placed after two patients experienced suspected adverse reactions during treatment with LentiGlobin for sickle cell disease in a Phase 1/2 study called HGB-206.
One patient developed acute myeloid leukemia, a type of blood cancer, but bluebird reported to the FDA that the case was “very unlikely” to have been related to the lentiviral vector used in LentiGlobin.
Another patient was thought to have developed myelodysplastic syndrome, a disorder caused by blood cells that are poorly formed or don't work properly, but the diagnosis was revised to indicate transfusion-dependent anemia.
“Patient safety continues to be our utmost priority, and we are grateful for the close partnership with the FDA, investigators, scientists and most importantly, patients, who all contributed to the assessments of the adverse events in HGB-206,” said Andrew Obenshain, president of severe genetic diseases at bluebird bio.
“As pioneers in gene therapy, we remain committed to advancing the field through our learnings,” Obenshain said. “Over the past four months, we have gained deeper knowledge and understanding of the pathophysiology of sickle cell disease that will allow us to better serve patients and the broader community. We look forward to resuming our clinical programs and continuing to advance toward major regulatory submissions for sickle cell disease and beta-thalassemia.”
LentiGlobin is an investigational treatment being studied as a potential one-time therapy for sickle cell disease, an incurable genetic disorder that causes malformed red blood cells that die early, leaving a deficit of healthy red blood cells.
LentiGlobin uses a lentiviral vector to deliver a modified copy of the beta-globin gene into stem cells. That increases the production of hemoglobin, the protein in red blood cells that carries oxygen throughout the body.
LentiGlobin has not been approved for use in any country but has been granted orphan drug designation, fast track designation, regenerative medicine advanced therapy designation and rare pediatric disease designation for sickle cell disease in the United States. It has also received orphan medicinal product designation from the European Commission and priority medicines eligibility by the European Medicines Agency.
The same lentiviral vector used in LentiGlobin is also used in Zynteglo, bluebird’s gene therapy for treating transfusion-dependent beta-thalassemia. For that reason, bluebird had decided voluntarily to suspend marketing of Zynteglo until the FDA’s lifting of its clinical holds.
Zynteglo is a one-time gene therapy used to treat beta-thalassemia in patients 12 years and older. People with the genetic condition can’t make enough beta-globin, a component of hemoglobin, causing low red blood cell levels and a need for frequent blood transfusions.
Zynteglo has been given conditional authorization for use in the European Union and the United Kingdom. That status allows use of the therapy but requires bluebird to provide additional data each year for review by the European Medicines Agency.
Manufacturing presence in Durham
Bluebird, based in Cambridge, Mass., is developing gene therapies for severe genetic diseases and cancer using three gene therapy technologies: gene addition, cell therapy and gene editing.
In 2019, the company dedicated a 125,000-square-foot facility in Durham to produce lentiviral vector for investigational gene and cell therapies. The facility is large enough to accommodate “significant future expansion,” including the possibility of manufacturing commercial drug product, the company said at the time.
The company received an Economic Development Award from the North Carolina Biotechnology Center tied to meeting job-creation targets in North Carolina and is also receiving bioscience-specific employee training support from the N.C. Community College System.
Bluebird has additional locations in Seattle and Zug, Switzerland. The company has about 1,100 employees across the United States and Europe.
Bluebird’s stock shares are traded on the NASDAQ market under the ticker symbol BLUE.