HuidaGene Therapeutics has received Rare Pediatric Disease Designation (RPDD) from the FDA for HG004 to treat inherited retinal disease (IRD) caused by RPE65 (RPE65-IRDs).
Refresh me on HuidaGene.
Based in Shanghai, China and New Jersey, the global, clinical-stage biotechnology company has been focused on the development of clustered regularly interspaced short palindromic repeats (CRISPR)-based genetic medicine.
And RPDD?
A Rare Pediatric Disease Designation (RPDD) is granted by the FDA for drugs under development for rare childhood diseases when the following criteria has been met:
- The drug must be intended for the prevention or treatment of a rare pediatric disease (a life-threatening or serious condition primarily affecting individuals 18 years old and younger)
- Adequate documentation or prevalence data must demonstrate that the intended pediatric disease or condition is rare (the overall patient population for the disease must be 200,000 individuals or less in the U.S.)
- Must not be for an active ingredient that is already approved for use
- There must be supportive data suggesting that the drug may be effective in the rare pediatric disease or condition.
Why is this important?
Companies with drugs in the RPDD program that have received an approval to qualify for a priority review voucher (PRV) may be eligible to receive an expedited 6-month priority review for any marketing applications that follow (such as an IND or new drug application [NDA]), or be sold or traded.
For HuidaGene, this accelerated review process could be of significant economic benefit for the company’s marketing approval goals.
Now tell me about HG004.
HG004 is a novel subretinal injection designed to treat RPE65 retinopathies such as Leber Congenital Amaurosis 2 (LCA2), severe early childhood-onset retinal dystrophy (SECORD), early-onset severe retinal dystrophy (EOSRD), and retinitis pigmentosa (RP).
Any prior FDA activity?
Yes! In January 2023, the FDA cleared the therapy for an investigational new drug (IND) application, and in April 2023, it was granted orphan drug designation (ODD) to support the launch of a multinational trial assessing HG004 for IRDs.
And clinical data?
A head-to-head, preclinical study compared equal dosages of HG004 and adeno-associated virus serotype 2 (AAV2). Retinal function recovery was found to increase by 67.6% for HG004 and 35.8% for AAV2 products when assessed using an RPE65 gene knockout murine disease model.
Click here to find out more on how its performance has compared to AAV2.
What about that multinational trial?
In collaboration with Cholgene Therapeutics, Inc., the open-label, multiple-cohort, dose-escalation phase 1/2 study (NCT05906953) will evaluate an estimated 20 patients (ages 6 to 50 years of age) with RPE65-associated LCA2 using one master protocol.
Safety, tolerability, efficacy, and long-term clinical durability of one HG004 injection in three doses (low, medium, and high) will be assessed for up to 52 weeks.
Talk about patient criteria.
Aside from a diagnosis of RPE65-associated LCA2, patients must have a visual acuity (VA) of ≤ 20/80 or visual field > 20 degrees in the eye to be injected.
See here for additional inclusion and exclusion criteria.
And what’s being measured?
Primary outcomes including ocular and non-ocular adverse events (at 52 weeks), while secondary outcomes include the change from baseline in:
- Best-corrected visual acuity (BCVA) of letters based on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart.
- Visual fields of full-field stimulus threshold test in log cd.s/m2.
When can we expect data from this?
Considering enrollment has yet to begin (according to Clinical Trials, it’s slated for September 2023, with completion in December 2025), likely in 2024.
Stay tuned for updates in the meantime!