FDA Appears to Be Granting Zombie Rare Pediatric Disease Designations Waiting for the Rare Pediatric Disease Priority Review Voucher Program to be Revived

The rare pediatric disease priority review voucher program remains in its sunsetting state – the current authority only allows for granting of such vouchers if the drug was designated as a drug for a rare pediatric disease not later than December 20, 2024, and for which a “rare pediatric disease product application” is approved not later than September 30, 2026.

However, as we suggested in a recent blog post, the statute did not actually provide any limitations on FDA’s authority to grant rare pediatric disease designations, only its authority to grant vouchers.  As such, we urged companies to continue to request, and FDA to continue to grant, rare pediatric disease designations in the hopes that Congress would extend the program once again, as it seemed quite close to doing in December.

In the meantime, the Pink Sheet confirmed that FDA was continuing to review rare pediatric disease designation requests.  However, we were not aware of any actual grants of rare pediatric disease designations past the December 20, 2024, deadline – until recently.

On February 5, 2025, a press release caught our eye – Arbor Biotechnologies announced that ABO-101, its investigational therapy for the treatment of primary hyperoxaluria type 1 (PH1), received a rare pediatric disease designation.  While this press release did not specify the date that it was granted, it noted that it “closely follow[ed]” FDA’s clearance of its IND.  In an earlier press release on December 19, 2024, Arbor Biotechnologies had announced FDA’s clearance of its IND for PH1.  As such, this seems very likely to be an example of FDA granting a rare pediatric disease designation even after the December 20, 2024, deadline.

While this press release caught our eye, we went back and looked to see if there were others we had missed.  It turns out that there have been several recent press releases announcing rare pediatric disease designations following the deadline of December 20, 2024.  These include (with date of announcement):

• January 8: ViGeneron GmbH, for its investigational therapy for retinitis pigmentosa caused by mutations in the CNGA1 gene
• January 20: PYC Therapeutics, for its investigational therapy for retinitis pigmentosa type 11
• January 22: Tikun Therapeutics, for its investigational therapy for familial dysautonomia
• January 22: MeiraGTx, for its investigational therapy for Leber congenital amaurosis due to GUCY2D mutations
• January 23: NS Pharma, for its investigational therapy for Duchenne muscular dystrophy with confirmed gene mutations amenable to exon 50 skipping therapy
• January 28: SEED Therapeutics, for its investigational therapy for solid tumor indications

This may not be an exhaustive list, especially given that FDA does not announce the issuance of rare pediatric disease designations.  However, given the timing of these announcements, it appears likely that at least some of these represent FDA granting rare pediatric disease designations following the December 20, 2024, deadline.

It is important to note that even prior to the deadline, a rare pediatric disease designation was not a guarantee for a priority review voucher.  Sponsors were still required to include a request in their NDA/BLA, and the application had to meet the relevant criteria described in 21 U.S.C. § 360ff for a “rare pediatric disease product application” at the time of approval.  However, rare pediatric disease designations granted after December 20, 2024, seemingly such as the ones listed above, are currently explicitly excluded from eligibility for a rare pediatric disease priority review voucher – absent future congressional action.

We also note that the statute (at 21 U.S.C. § 360ff(d)(2)) technically states that sponsors “shall” request rare pediatric disease designation “at the same time” as a request for orphan drug designation or a fast track designation.  In guidance, FDA explained that there may be circumstances where a sponsor does not wish to submit a rare pediatric disease designation request at this time; in such cases, FDA stated its willingness to accept and review such designation requests (so long as they are received prior to NDA/BLA filing), but noted that the typical statutory 60-day response deadline does not apply.  As such, sponsors may find themselves in a situation where, in order to receive a timely response to a rare pediatric disease designation request, they have to submit one at the time of a planned orphan drug designation or fast track designation request without knowing whether a priority review voucher will ultimately be available.  This is, understandably, a difficult situation for sponsors.

We wish to applaud FDA for continuing to grant these designations, and we congratulate the sponsors in their efforts.  While the program is currently closed without a qualifying ticket for entry, these sponsors have set themselves up well to take advantage of the program should Congress reauthorize it and bring these zombie designations back to life.  We remain hopeful that this will happen in the near future.