FDA Accepts Orchard’s BLA for Rare Disease Gene Therapy Behind EU Approval

Gene therapy_iStock, Ilya Lukichev

Pictured: Gene therapy illustration showing an injection targeting a specific DNA site/iStock, Ilya Lukichev

The FDA on Monday accepted Orchard Therapeutics’ Biologics License Application for OTL-200, an investigational gene therapy for rare disease metachromatic leukodystrophy that was approved in Europe in 2020.

The U.S. regulator granted Orchard’s application its Priority Review designation, which shortens the regulatory review period to six months, as opposed to 10 months under regular circumstances. The FDA’s verdict is due on March 18, 2024.

In a statement, Orchard CEO Bobby Gaspar said that the BLA acceptance is an important victory for metachromatic leukodystrophy (MLD) patients and their families, “who for too long have dealt with the unimaginable burden of going through the diagnostic odyssey, being told there were no treatments beyond supportive care, and then having to watch their child slip away.”

While the FDA’s review is ongoing, Orchard will also work “in parallel” to potentially launch OTL-200 in 2024 and make the treatment available to patients “as quickly as possible,” Gaspar said.

Occurring in approximately one in every 100,000 live births, MLD is a rare and heritable disorder that afflicts the metabolic system. It is caused by a pathologic mutation in the arylsulfatase-A (ARSA) gene, which under healthy circumstances encodes for an enzyme that helps break down a type of fatty substance called sulfatides.

This genetic aberration leads to the build-up of sulfatides in various organs, including the brain, kidneys and spleen. The accumulation manifests as motor, cognitive and behavioral problems, as well as seizures and spasticity. As the disease progresses, MLD patients lose their ability to move, talk, eat and see—and ultimately die.

OTL-200, also known as atidarsagene autotemcel, addresses the underlying cause of MLD by delivering functioning copies of the ARSA gene. The investigational therapy uses hematopoietic stem cells which have been genetically modified to encode for the human ARSA gene.

To support its regulatory bid with the FDA, Orchard has provided data from two prospective non-randomized studies, enrolling a total of 39 children with early-onset MLD. Results from these studies showed that the investigational gene therapy could preserve motor function and cognitive development in treated children.

In addition, with more than 250 cumulative patient-years of follow up, OTL-200 was well-tolerated and induced no treatment-related serious adverse events or deaths.

This mechanism of action—along with a promising clinical profile—has won OTL-200 regulatory approval in the European Union, where it is marketed under the brand name Libmeldy, and has since been used in at least six countries. The FDA has also granted the candidate its Rare Pediatric Disease and Regenerative Medicine Advanced Therapy designations.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. He can be reached at tristan@tristanmanalac.com or tristan.manalac@biospace.com.

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