FDA grants orphan drug designation for HG004, HuidaGene’s gene therapy for IRDs

The FDA has granted orphan drug designation for HG004, a gene replacement therapy by HuidaGene. (Image Credit: Adobe Stock/Nitiphol)

HuidaGene Therapeutics announced that the US Food and Drug Administration (FDA) has granted orphan drug designation (ODD) for HG004, a gene replacement therapy that seeks to advance the treatment of patients who are affected by inherited retinal diseases (IRDs) caused by RPE65 mutations. HG004 is a gene replacement therapy drug which uses the recombinant non-adeno-associated virus serotype 2 (non-AAV2) vector to deliver a functional human RPE65 gene to the retina to restore, treat, and prevent blindness in those patients with RPE65 mutation-associated IRDs.

These gene mutations are associated with a group of rare blinding conditions that affect the retina and can be passed on to children, including Leber's congenital amaurosis, severe early childhood-onset retinal dystrophy, early-onset severe retinal dystrophy, and retinitis pigmentosa. The IRDs typical onset is between birth and 5 years of age and exhibit several common clinical findings, chiefly night blindness, progressive loss of visual fields, and loss of central vision. An estimated 6,600 individuals living in the US are diagnosed with RPE65 mutation-associated IRDs in 2023.

“Receiving ODD is an important milestone as we are advancing our HG004 gene replacement therapy program to clinical trial designed to provide safe, durable, and high-quality treatment to children and adults suffering from RPE65 mutation-associated inherited retinal diseases,” said Xuan Yao, PhD, co-founder and chief executive officer of HuidaGene. “It also underscores the importance of bringing this novel therapy to patients with severe visual impairment or blindness, and strongly motivates us to expedite the clinical development of HG004.”

ODD will accelerate drug development and registration action in the US and allow HG004 to be eligible for certain development incentives, including FDA support for clinical studies. In January 2023, the FDA cleared the HG004 investigational new drug application for the company’s planned multinational clinical trial and is currently being reviewed by the China's National Medical Products Administration (NMPA) on this first AAV gene replacement therapy master protocol in different countries including China.