This week we discuss the FDA’s approval of Isembyld for SMA, the approval of a gene therapy for MPS IIIA, and the FDA’s Center for Devices and Radiological Health new Rare Disease Impact Initiative.
Approval of Isembyld for Spinal Muscular Atrophy
The FDA announced the approval of Isembyld (apitegromab-mstn) to treat patients 2 yrs and older with spinal muscular atrophy who are currently receiving SMN2-targeted therapy.
SMA is a genetic condition in which patients lose spinal muscle function due to a mutation in the SMN1 gene. There are three therapies for this condition: one is a gene therapy that replaces the SMN1 gene, and the other two, significantly cheaper therapies, increase the activity of a backup gene, SMN2, to increase the missing SMN protein.
This new drug is an add-on therapy to those two latter therapies that target SMN2.
It will be interesting to see how payers and physicians decide where this fits, particularly when you’re treating a relatively small patient population with very expensive therapies.
There’s another interesting piece to this approval. Scholar Rock received a pediatric priority review voucher. These vouchers are intended to encourage companies to develop treatments for children, something that historically has been more difficult because pediatric clinical trials can be challenging to conduct. We’re seeing pharmaceutical companies increasingly pursue these opportunities.
Gene Therapy Approved for MPS IIIA
The FDA also approved a gene therapy for MPS IIIa, also referred to as Sanfilippo syndrome type A.
MPS IIIa is a devastating disease. These children start out looking very healthy, but as toxic levels of heparin sulfate accumulates in their cells, these children begin a cognitive and behavioural decline that completely disrupts the family.
The results from the study leading to the approval is impressive. Instead of the typical cognitive decline seen in these children, adding gene therapy stabilized or improved their cognitive abilities.
The therapy is priced at $3.9 million for a single treatment. That’s obviously an enormous dollar amount, and payers generally don’t like paying that kind of cost upfront, even when a one-time therapy could potentially be less expensive over the long term than years of continuous treatment.
It’s also an important moment for Ultragenyx. This is their second FDA approval in the last month, and they’ve established 25 centers capable of delivering the gene therapy, with plans to expand that to 40.
So this isn’t just about getting therapy approved. It’s also about building the infrastructure to actually get these therapies to patients.
Rare Disease Impact Initiative
The FDA’s Center for Devices and Radiological Health (CDHR) introduced its Rare Disease Impact Initiative.
While we tend to focus on drug therapies to manage patients with rare conditions, there are many diseases that rely on medical devices to manage and/or monitor patients. At last count, the FDA listed over 2000 devices that are being used to help people with rare conditions.
The FDA’s Rare Disease Impact Initiative is designed to help medical-device developers work more directly with the FDA as they develop products for rare disease populations.
It’s another part of the rare disease ecosystem that we think deserves more attention.
Looking Ahead
Several important FDA decisions are coming up.
September 26: Mirum’s therapy for fibrodysplasia ossificans progressiva, or FOP.
September 27: Tlevar Therapeutics’ therapy for cholangiocarcinoma and Praxis’ therapy for SCN2A and SCN8A deficiencies.
September 28: Egetis Therapeutics’ orphan drug to treat patients with MCT8 deficiency.
References
FDA approves new SMA drug
FDA approves gene therapy for MPS IIIA
CDRH Rare Disease Impact Initiative