Rare Pediatric Disease Designation Granted to Treatment for Childhood Blindness

Mathew Shanley

It was announced this morning by MeiraGTx that the U.S. Food and Drug Administration’s (FDA) Offices of Orphan Products Development and Pediatric Therapeutics have granted the company Rare Pediatric Disease designation for its potential gene therapy for the treatment of certain patients with Leber Congenital Amaurosis (LCA), AAV2/5-OPTIRPE65 (A001).

A001, which previously received orphan drug designation from the FDA, is delivered via subretinal injection of up to 1 ml to cover as much of the retina as possible.

In up to 16% of all cases of LCA, the underlying deficit is in the RPE65 gene, which plays a major part in the regeneration of visual pigment after significant exposure to light. The genetic retinal degenerative disease is characterized by severe impairment in vision, beginning in infancy. The disease has the greatest impact on the retina, and progressively worsens over time.

According to the NIH, LCA occurs in approximately 2-to-3 per 100,000 newborns and is one of the most common causes of blindness in children.

A001 is intended specifically for patients with LCA due to mutations in the RPE65 gene.

It is an adeno-associated virus (AAV2/5) investigational gene therapy proposed to transport a codon-optimized RPE65 cDNA under the control of a synthetic RPE-specific promoter to the back of the eye. The company is in the process of conducting an open label, multi-center Phase 1/2 dose escalation trial of A001 in patients detected to have severe early onset LCA2, and the primary endpoint is the evaluation of the treatment’s safety profile.

"The FDA's decision to award rare pediatric disease designation to A001, along with the previously received orphan drug designation, underscores the urgency of developing effective therapies for rare pediatric diseases like LCA2," said Zandy Forbes, Ph.D., President and CEO of MeiraGTx in a press release. "We are pleased with the rapid progress in our LCA2 clinical study and we are excited to be including pediatric patients with this severe genetic disorder in both Europe and the U.S."

The secondary endpoints of the study include improvement in visual function including a mobility maze, retinal function, retinal structure and quality of life measures.

If A001 is approved by the FDA for this indication, MeiraGTx will be eligible to receive a Priority Review Voucher. The voucher can be used on any of the company’s future drug to reduce the FDA review time by 4 months, and it is also transferable.

Many small biotech companies, when awarded a voucher, sell it to larger pharmaceutical companies. In February, Sarepta sold its voucher for $125 million to Gilead Sciences.

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