bluebird bio has submitted a Biologics License Application to the US Food and Drug Administration (FDA) for its sickle cell disease (SCD) gene therapy.
The application, which includes a request for priority review, is specifically for lovotibeglogene autotemcel (lovo-cel) to treat SCD patients aged 12 years and older who have a history of painful complications associated with the disease.
Affecting approximately 100,000 people in the US, SCD is a life-long, incurable genetic disease causing red blood cells to take a distinct crescent shape, which can block blood vessels and affect the way oxygen is carried around the body.
The disease can cause serious health problems including anaemia, fatigue, episodes of pain and chronic end-organ damage.
Andrew Obenshain, bluebird’s chief executive officer, said: “The severity of SCD, and its impact on patients and caregivers, has been underappreciated and overlooked for far too long. Transformative therapies for this community are long overdue.”
bluebird’s lovo-cel is an investigational one-time treatment designed to add functional copies of a modified form of the beta-globin gene into a patient’s own haematopoietic stem cells.
Following treatment, a patient’s red blood cells can produce anti-sickling haemoglobin that decreases the proportion of sickle haemoglobin, with the goal of reducing sickled red blood cells, haemolysis and other complications.
The company’s submission is backed by efficacy results from 36 patients with 32 months of follow-up data and two patients with 18 months follow-up. Safety data from 50 patients, including six patients with six or more years of follow-up, is also included in the application.
The filing comes just months after the US regulator lifted its partial clinical hold on bluebird’s lovo-cel studies.
The trials were placed on a partial hold in December 2021 relating to an investigation by bluebird into an adolescent patient with persistent, non-transfusion-dependent anaemia following treatment with lovo-cel.
Results from a detailed investigation of the case were presented at the American Society of Hematology Annual Meeting and Exposition, alongside details from another case of persistent anaemia in an adult patient following treatment with the gene therapy.
It was found that both patients had a specific genotype known as alpha thalassaemia trait, which was subsequently added to exclusion criteria for ongoing studies.