Sickle Cell Gene Therapies Face Unique Uptake Challenges

Late in 2023, the FDA approved 2 gene therapies for sickle cell disease,^1,2 although they are not being used as much as expected, which Kevin Niehoff, PharmD, BCMAS, associate director, Market and Financial Insights, IPD Analytics, attributes to a few factors that make these gene therapies different than others approved before them.

This transcript has been lightly edited for clarity.

Transcript

It's been almost a full year since the first sickle cell gene therapies were approved by the FDA. Reports are that the rollout and uptake has been slow. What do you attribute this to?

I think the main driving factor is potentially overestimating the target market. I think that, superficially, you might view it as there's 100,000 patients in the US give or take with sickle cell disease, but I think what may have been missed is that there are varying degrees of severity. There's also, when we're talking about the gene therapies that require myeloablative conditioning, comparing those to the more traditional bone marrow transplant as a treatment, I think it's much more difficult to tease those 2 apart for patients that are having eligible matches.

I really think that the actual target market here is those patients that aren't controlled with traditional therapies like hydroxyurea, and also are not eligible for a bone marrow transplant. As I mentioned, that target market is actually a much smaller slice of the larger patient population.

And I think another large part is that with these types of therapies compared to maybe other gene therapies in Duchenne muscular dystrophy or spinal muscular atrophy [SMA], you have progressive diseases, whereas sickle cell isn't quite progressive. They don't the luxury of time to make a decision or wait for different therapies, and I think that the progressive nature of Duchenne muscular dystrophy or SMA is really driving their gene therapy uptake. Whereas with some of the hemophilia products and, obviously, the sickle cell products, you're seeing that there are other effective treatment options and alternatives and really not as much of a time crunch, if you will, from the patient perspective.

I think a lot of the things that are driving uptake in other gene therapies are not present in the sickle cell space.

References

1. Bonavitacola J. FDA approves exagamglogene autotemcel, first CRISPR gene-editing therapy for SCD. AJMC®. December 8, 2023. Accessed October 16, 2024. https://www.ajmc.com/view/fda-approves-exagamglogene-autotemcel-first-crispr-gene-editing-therapy-for-scd

2. Hoffman M. FDA approves bluebird bio’s lovo-cel gene therapy for sickle cell disease. CGTLive™. December 8, 2023. Accessed October 16, 2024. https://www.cgtlive.com/view/fda-approves-bluebird-bio-lovo-cel-lyfgenia-sickle-cell-disease