Bluebird bio could finally get gene therapy approved in the United States.
Cambridge Biotechnology, MA, announced Monday that the FDA had accepted and prioritized the review of Zynteglo, its gene therapy for beta-thalassemia, a rare blood disorder. The announcement sets up a fast-track FDA decision by May 20, 2022.
Priority review does not guarantee approval, and more than a few recent biotechs have been rejected after receiving the designation, including Incyte, Sesen and Provention. But it represents a substantial step forward for a therapy that has seen repeated setbacks and a claim that has been slapped with a letter of denial of filing.
The approval rate for candidates for priority review by the FDA hovered between about 70% and 90% between 2011 and 2019, compared to just over 60% for drugs given the standard 10-month reviews.
Acceptance is a long time coming for bluebird. The company presented its first results from a Phase III beta thalassemia trial in June 2017 and first obtained conditional approval in Europe in June 2019. At the time, Bluebird also presented spectacular data on a similar single treatment for sickle cell anemia. , then then CEO Nick Leschly said the company plans to launch treatment for beta thalassemia in 2020 and sickle cell disease in 2022.
But the company then faced repeated delays for both candidates, struggling to finalize its manufacturing process or reach an agreement with regulators on how best to measure the quality of its product. Bluebird’s arc has become a parable of the importance of manufacturing in gene therapy, where treatments are so technically complex that producing them reliably on a large scale can be as sophisticated a challenge as proving it works.
The delays appeared to be part of what caused the company to split in two, turning its cancer division into a biotech called 2seventy, so bluebird could devote most of its resources to approving its gene therapies for rare genetic diseases.
Beta thalassemia, which affects approximately 1 in 100,000 Americans, is not expected to be a huge market for bluebirds in the United States. But an approval would be a key step in keeping bluebird on the promise it has made for years.
This is especially important after biotech decided to pull Zynteglo, along with the rest of its gene therapy portfolio, from the European market, where there is a much larger population of beta thalassemia patients. The company said European governments were unwilling to pay a fair price for the treatment.
In Germany, the only country for which bluebird has disclosed details, authorities have offered $ 790,000 for the one-time treatment, with the payment rising to $ 950,000 if the therapy still works after five years. The numbers roughly match the $ 900,000 price analysts expected bluebird to put in therapy ahead of launch. Bluebird wanted $ 1.8 million paid over 5 years, with payments contingent on the patient’s response.
A bluebird spokesperson, alluding to the company’s turbulent pricing history, said the company has yet to set a price for Zynteglo in the United States and will not comment on the structure of payment.
“We have learned first-hand that there is no one-size-fits-all approach to accessing and reimbursing gene therapy and are ready to try a number of payment structures that meet needs and priorities. unique to patients, providers and payers without creating additional barriers or complexities, ”she said.
She added that “several” patients had received Zynteglo before its withdrawal in Europe and that several others who had already consented to the treatment will still receive it. The deployment there was disrupted by manufacturing delays and a security alert (which ultimately did not materialize); bluebird said in quarterly documents that it had started collecting income from the drug, but that the income was “intangible”.
US approval would make Zynteglo the third gene therapy approved in the United States, after Luxturna from Spark and Zolgensma from Novartis. It would be the first approved ex vivo gene therapy, where cells are removed from a patient, modified and then reinjected – as opposed to in vivo gene therapy, where a patient’s cells are changed directly in their body.
Although not a universal cure, Zynteglo has been shown to be a very effective treatment for beta thalassemia, a condition characterized by monthly blood transfusions which can be debilitating over time. Of 36 evaluable patients in the company’s trials, 32 have not required transfusions for at least 12 months.