Touchdown for Rocket as its first gene therapy gets US okay
At its second attempt, Rocket Pharma has won FDA approval for its gene therapy for severe leukocyte adhesion deficiency type I (LAD-I), a rare and life-threatening immune disorder that leaves patients vulnerable to life-threatening infections.
The gene therapy, Kresladi (marnetegragene autotemcel), is the first targeted treatment for LAD-I, which until now has been treated with aggressive antibiotic therapies to fight infections and – where possible – an allogeneic haematopoietic stem cell transplant (HSCT), which can be curative, but relies on having a donor match and is associated with serious risks.
Kresladi was turned down by the FDA in June 2024 with a request for more information about its manufacturing processes, prompting Rocket to slash its headcount, and was refiled last October. It has now been approved for the treatment of paediatric patients with LAD-I caused by mutations in the ITGB2 gene who don't have a matched sibling donor for an HSCT.
The treatment is made from the patient's own haematopoietic stem cells, which are genetically modified to introduce functional copies of the ITGB2 gene. It is given as a single intravenous dose after myeloablative conditioning to eliminate their defective stem cells and prepare the bone marrow for the new, modified cells.
LAD-I is vanishingly rare, with an incidence estimated at one in a million people and fewer than 400 recorded cases worldwide, and it is estimated there may only be around 50 people living with the disease in the US. Rocket hasn't yet released its launch and pricing plans for Kresladi, but like other one-shot gene therapies for ultra-rare diseases, it is expected to cost millions of dollars.
There will likely be a strong case for reimbursement, given that Kresladi achieved 100% overall survival at two years in the phase 1/2 trial carried out in support of its marketing application, and LAD-I has a mortality rate of around 75% in the first two years of life.
The approval also earns the Cranbury, New Jersey biotech a rare paediatric disease Priority Review Voucher (PRV), which can be worth as much as $200 million if sold to a third party.
The FDA announced the approval after trading hours yesterday, and shares in Rocket were up around 8% pre-market this morning.
It is the second FDA approval for a rare disease gene therapy this week, after Denali Therapeutics' Hunter syndrome therapy Avlayah (tividenofusp alfa), and will boost sentiment among rare disease therapy developers after concerns that the agency was raising the requirements for approval.
The green light for Kresladi comes a few months after it decided to withdraw marketing applications for its RP-L102 gene therapy for Fanconi anaemia, for commercial - rather than safety or efficacy - reasons, in order to devote its resources to Kresladi.
Image by tommy pixel from Pixabay
