Investigational RNA therapy QR-421a for USH2A mediated retinitis pigmentosa & Usher syndrome

Close-up of an eye of a man

QR-421a is an investigational RNA therapy that aims to stop vision loss or restore vision in people with retinitis pigmentosa (RP) and Usher syndrome due to mutation(s) in a specific part of the USH2A gene, called exon 13.

QR-421a

Disease
USH2A mediated retinitis pigmentosa and Usher syndrome

Program QR-421a for USH2A mediated retinitis pigmentosa and Usher syndrome is now in the phase 1/2 phase

QR-421a is an RNA therapy that aims to prevent vision loss or restore vision in retinitis pigmentosa (RP) and Usher syndrome type 2 due to mutations in exon 13 of the USH2A gene.

How does QR-421a work?

QR-421a aims to prevent vision loss or restore vision in people with Usher syndrome and retinitis pigmentosa due to mutation(s) in exon 13 of the USH2A gene. Mutations in exon 13 are a common cause of these diseases. The mutations cause a mistake in the USH2A RNA and therefore the cell cannot use the RNA to produce a working USH2A protein that is essential for vision. 

QR-421a works by binding to the mutated USH2A RNA and exclude exon 13 from the RNA. This approach is known as exon skipping. The cells in the retina can then produce a slightly shorter but functional USH2A protein.

QR-421a clinical trials

We are conducting the Stellar trial, a Phase 1/2 clinical trial of QR-421a, to test whether it is safe and leads to better vision. Interim findings from the trial were encouraging. We are now completing this Phase 1/2 trial in order to move to later stage clinical trials.

Learn more about clinical trials and why you should consider participating.

Stellar study - Phase 1/2 clinical trial

Ongoing, recruiting

Stellar clinical trial logo

Stellar is an international clinical trial of QR-421a in adults with Usher syndrome and retinitis pigmentosa (RP) due to mutation(s) in exon 13 of the USH2A gene. Participants receive a single intravitreal (into the eye) injection or undergo a sham-procedure (simulated intravitreal procedure but no study medicine administered). Study participation will last 24 months.

Interim clinical trial findings

Three-months interim findings from Stellar suggested QR-421a was safe and well tolerated. In two out of eight participants in the treated groups QR-421a showed early and encouraging evidence of activity. A similar response was not observed in the six participants included in the sham procedure control group.

Based on these early encouraging findings we will continue the trial as designed at expert centers in North America and Europe.

More about Stellar and participation

Designations granted to QR-421a by authorities

  • FDA orphan drug designation
  • EMA orphan drug designation
  • FDA fast track designation 
  • FDA rare pediatric disease designation