An FDA mistake signals likely approval for first therapy for children born without a thymus
The FDA on Thursday accidentally published a notice announcing the award of a priority review voucher to rare disease drug developer Enzyvant for its new regenerative therapy for the treatment of pediatric patients with congenital athymia.
The only problem? The treatment still hasn’t won FDA approval. The agency told Endpoints the notice was published in error and will be withdrawn. The release of the PRV notice, which typically come days or weeks after an approval is announced, puzzled the company.
Vivek Ramaswamy’s Enzyvant, sold as part of a $3 billion deal with Sumitomo Dainippon Pharma, said in an emailed statement that it “has not received approval notification from the FDA. Our PDUFA date remains October 8. Enzyvant found out about the PRV when it was published in the Federal Register and is working with the agency to determine what this means.”
The treatment in question, potentially to be known as Rethymic (allogeneic processed thymus tissue-agdc), would be the first for the ultra-rare condition in which children are born without a thymus, known as congenital athymia, which can lead to profound immunodeficiency issues and make them highly susceptible to infections. According to Enzyvant, patients with congenital athymia, usually about 20 per year in the US, die from infections or autoimmune manifestations by age two or three.
This has been a long road to approval (if an approval occurs) as Enzyvant received a CRL for the treatment in December 2019 due to several regulatory requests related to chemistry, manufacturing and controls.
Enzyvant CEO Rachelle Jacques told Endpoints News in April that it resolved issues related to the CRL:
We did need to do some facilities construction and we did that during Covid. That’s something that we didn’t anticipate immediately when we had the letter in our hands, but certainly as we talked with the agency that was very clear that was a solution. A lot of the other work was really just documenting at a very granular level some of the processes and so on as well as some additional studies we did to supplement the data we provided on the overall manufacturing process — and those were long lead time items as well.
Editor’s note: Article updated with comment from FDA.