Why Haven't More Patients Been Treated With the Gene Therapies for Sickle Cell Disease? | AMCP Nexus 2024

Approximately 100,000 people in the U.S. have one of group of inherited blood disorders that come under the heading of sickle cell disease. But that doesn’t make them all good candidate for one of the two FDA-approved gene therapies for sickle cell disease, Vertex’s Casgevy (exagamglogene autotemcel) and Bluebird Bio’s Lyfgenia (lovotibeglogene autotemcel), according to Kevin Niehoff, associate director at IPD Analytics and a panelist today at a session on sickle gene therapies at the 2024 Academy of Managed Care Pharmacy (AMCP) meeting in Las Vegas.

“Instead of having a potential patient pool of about 100,000 in the US, it's probably a lot closer to maybe 15,00 or 20,000,” Niehoff said in a video interview with Managed Healthcare Executive (MHE) prior to the meeting.

Niehoff told MHE that Vertex has reported that 20 patients had initiated treatment process that leads to treatment with Casgevy as of mid-2024 and that Bluebird Bio has reported that just four patients had started the arduous process that leads to treatment with Lyfgenia

Casgevy is priced at $2.2 miliom per treatment and Lyfgenia at $3.1 million. But Niehoff said he doesn’t see those high prices, which are borne by insurers, as reason for the low uptake. There are alternatives to gene therapy for patients with sickle cell disease, he noted, including stem cell transplants (sometimes called bone marrow transplants) that can be curative. Hydroxyurea can be used to treat the disease, said Niehoff, who also mentioned that sickle cell disease varies in severity.

“I think that the gene therapies are going to be used in patients that can't be controlled with existing therapies and don't have a [bone marrow] donor match,” Niehoff said.

Price, he said, is not as big a barrier to Casgevy and Lyfgnia “as where that therapy actually slots in."