HUIDAGENE THERAPEUTICS RECEIVES FDA RARE PEDIATRIC DISEASE DESIGNATION FOR HG004 TO TREAT INHERITED BLINDNESS

• HG004 is a one-time, direct-to-RPE treatment of inherited retinal disease caused by mutations in the RPE65 gene
• ^~10-fold lower vector doses in multiregion, multicenter HG00402 trial than other AAV2 gene therapy clinical trials
• HG004 was previously granted orphan drug designation (ODD) for RPE65-IRD on 31 March 2023

SHANGHAI and CLINTON N.J., Aug. 7, 2023 /PRNewswire/ -- HuidaGene Therapeutics (辉大基因，"HuidaGene"), a clinical-stage biotechnology company focused on developing CRISPR-based programmable genomic medicines, today announced the U.S. Food and Drug Administration (FDA) had granted Rare Pediatric Disease Designation (RPDD) to HG004 for the treatment of inherited retinal disease caused by RPE65 mutations (RPE65-IRDs). The FDA grants RPDD to incentive development of new treatments for serious or life-threatening diseases that primarily affect children ages 18 years or younger with fewer than 200,000 people affected in the U.S. The RPDD program allows for a sponsor who receives an approval to qualify for a priority review voucher (PRV) that can be deemed to receive an expedited six-month priority review for any subsequent marketing application or may be sold or transferred. PRVs have historically commanded prices in excess of $100 million USD with the highest price paid for a PRV was $350 million USD. For a large company launching a billion-dollar drug, the six-month acceleration in regulatory review can be of substantial economic value. Most recently, Sarepta Therapeutics sold a PRV for $102 million USD.

"This Rare Pediatric Disease designation from the US FDA highlights the significant unmet medical need that HuidaGene is seeking to address with HG004 for RPE65-IRDs," said Alvin Luk, Ph.D., M.B.A., C.C.R.A., Co-founder and Chief Executive Officer of HuidaGene. "HG004 was granted both RPDD and orphan drug designation (ODD) by the US FDA in March, allowing tax credits for clinical development, exemptions for certain FDA application fees, 7-year of market exclusivity, and assistance in the drug development process. We look forward to advancing HG004 in the clinic and remain steadfast in our commitment to answering patients worldwide."

"We are pleased to have received another significant regulatory feedback from the US FDA underscoring the dire need for a treatment option of this devastating inherited blindness," said Linyu Shi, Ph.D., Co-founder and Chief Scientific Officer of HuidaGene. "Data from our preclinical studies have shown that HG004 demonstrates significant superiority than AAV2-hRPE65 (LUXTURNA like) in the recovery of retinal function of the Rpe65^-/- mice. We are committed to delivering transformative genetic medicines for rare genetic diseases globally."

About Inherited Retinal Disease Caused by RPE65 Mutations
Inherited retinal disease (IRD) is a group of rare blinding conditions caused by mutations in any 1 of more than 250 genes. Leber's congenital amaurosis (LCA), severe early childhood-onset retinal dystrophy (SECORD), early-onset severe retinal dystrophy (EOSRD), and retinitis pigmentosa (RP), which may all be grouped under the heading of inherited retinal disease caused by RPE65 mutations (RPE65-IRD), are considered to represent a phenotypic continuum of the same disease. The RPE65-IRD with a typical onset between birth and five years of age exhibits several common clinical findings, chiefly night blindness, progressive loss of visual fields, and loss of central vision. Given the often severe and early visual loss associated with RPE65-IRD, other areas of development, including speech, social skills, and behavior, may also be delayed.

About HuidaGene -辉大基因
HuidaGene Therapeutics (辉大基因) is a global clinical-stage biotechnology company focusing on discovering, engineering, and developing CRISPR-based genetic medicine to rewrite the future of genomic medicine. Based in Shanghai and New Jersey, HuidaGene is committed to addressing patients' needs globally with various preclinical therapeutic programs covering ophthalmology, otology, myology, and neurology. We are currently advancing clinical programs in inherited retinal disease caused by RPE65 mutations and our preclinical pipeline, including programs in neovascular age-related macular degeneration, retinitis pigmentosa, hereditary hearing loss, Duchenne muscular dystrophy, and MECP2 duplication syndrome. Company's CRISPR-based therapeutics offer the potential to cure patients with life-threatening conditions by repairing the cause of their disease. HuidaGene is committed to transforming the future of genome-editing medicine.
For more information, please visit http://www.huidagene.com
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