QR-421a is a first-in-class investigational RNA-based oligonucleotide designed to address the underlying cause of the vision loss associated with Usher syndrome type 2 and non-syndromic retinitis pigmentosa (RP) due to mutations in exon 13 of the USH2A gene.

Fast Track designation is granted by FDA to drugs that are under development for serious conditions and have the potential to fulfill an unmet medical need. It was established with the intention to bring promising drugs to patients sooner by facilitating the development with more frequent FDA interactions and expediting the review process.

“We are very pleased with the Fast Track designation the FDA granted us for QR-421a. Patients with Usher syndrome, the leading cause of combined deafness and blindness, currently have no available therapies for their vision loss and this designation emphasizes the high unmet need in this disease,” said Daniel de Boer, chief executive officer of ProQR. “We are also looking forward to begin enrollment in the Phase 1/2 STELLAR clinical trial in the coming months with preliminary data expected in mid-2019.”