bluebird bio temporarily suspends trials of sickle cell gene therapy LentiGlobin

bluebird bio has announced that it will temporarily place phase 1/2 and phase 3 trials of its sickle cell disease (SCD) gene therapy LentiGlobin on hold after a report of a suspected unexpected serious adverse reaction (SUSAR).  

The reported SUSAR is a case of acute myeloid leukaemia. The patient, included in group A of the phase 1/2 HGB-206 study, was treated more than five years ago with bluebird gene therapy.

In a statement, bluebird said that it is investigating the cause of this patient’s AML diagnosis, to determine if there is a relationship between the use of the BB305 lentiviral vector in the manufacture of LentiGlobin for SCD.

Another SUSAR of myelodysplastic syndrome (MDS) in a patient from group C of HGB-206 was also reported last week, which bluebird also said it is currently investigating.

Although no cases of haematologic malignancy have been reported in any patient that has been treated with bluebird’s beta-thalassemia gene therapy Zynteglo (betibeglogene autotemcel; beti-cel), the company has temporarily suspended marketing of the treatment while it investigates the AML case.

This is because Zynteglo is manufactured using the same BB305 lentiviral vector used in LentiGlobin SCD.

“The safety of every patient who has participated in our studies or is treated with our gene therapies is the utmost priority for us,” said Nick Leschly, chief executive officer of bluebird.

“We are committed to fully assessing these cases in partnership with the healthcare providers supporting our clinical studies and appropriate regulatory agencies. Our thoughts are with these patients and their families during this time,” he added.

bluebird added that it will continue to work with regulatory agencies to complete its investigation, adding that the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) have been advised of both cases.