LEIDEN, The Netherlands & CAMBRIDGE, MA, USA I December 16, 2021 I ProQR Therapeutics N.V. (Nasdaq:PRQR), a company dedicated to changing lives through the creation of transformative RNA therapies for genetic eye diseases, today announced the first patients dosed in Phase 2/3 Sirius and Celeste clinical trials of investigational RNA therapy QR-421a for people with USH2A mediated retinitis pigmentosa (RP) and Usher syndrome.

“Retinitis pigmentosa (RP) and Usher syndrome associated with USH2A are inherited retinal diseases that can lead to blindness because there is no treatment available to stop the progressive vision loss”, said David Birch, Ph.D., investigator in the Sirius and Celeste studies at the Retina Foundation of the Southwest in Dallas, Texas, U.S. “These are the first, potentially pivotal trials for these conditions, that we see as a promising milestone that brings hope to the RP and Usher syndrome communities.”

“We are pleased to bring our second RNA therapy into potentially the final stage of clinical testing,” said Aniz Girach, M.D., Chief Medical Officer of ProQR. “In a previous clinical study, QR-421a appeared to be well tolerated and demonstrated concordant benefit in multiple measures of vision in treated eyes compared to untreated. Our goal is that the Sirius and Celeste studies further validate QR-421a’s ability to stabilize vision loss in people with USH2A mediated retinitis pigmentosa and Usher syndrome.”

About the Sirius and Celeste Clinical Trials

Sirius and Celeste, are two double-masked, randomized, sham controlled, 24-month, multiple dose studies to evaluate whether QR-421a is effective at stopping vision loss and whether it is safe and well-tolerated.

Adults and children (age 12 and up) with vision loss due to mutations in exon 13 of the USH2A gene will be enrolled in one of the studies, depending on baseline vision. In both studies participants are randomly assigned to three parallel study arms. In the two treatment arms, participants receive intravitreal injections with QR-421a at different doses (180 μg loading dose and 60 μg maintenance doses or 60 μg loading dose and 60 μg maintenance doses). In the third sham control arm the intravitreal injections are mimicked but no injection or study medication is given.

The Sirius study is planned to enroll 81 participants with advanced vision loss (baseline best corrected visual acuity (BCVA) of worse than 20/40). The primary endpoint in the study is mean change from baseline in BCVA at 18 months in the treated arms compared to the control arm.

The Celeste study is planned to enroll 120 participants with early to moderate vision loss (baseline BCVA of equal or better than 20/40). The primary endpoint in the study is mean change from baseline in static perimetry at 12 months in the treated arms compared to the control arm.

About USH2A Mediated Retinitis Pigmentosa and Usher Syndrome

Usher syndrome is the leading cause of combined deafness and blindness. People with USH2A mediated Usher syndrome are usually born with hearing loss and start to have progressive vision loss during adulthood. The vision loss can also occur without hearing loss in a disease called retinitis pigmentosa. Usher syndrome and retinitis pigmentosa can be caused by mutations in the USH2A gene. To date, there are no pharmaceutical treatments approved for vision loss associated with mutations in USH2A.

About QR-421a

QR-421a is a first-in-class investigational RNA therapy designed to address the underlying cause of vision loss in USH2A mediated retinitis pigmentosa and Usher syndrome due to mutations in exon 13 of the USH2A gene. QR-421a is designed to restore functional usherin protein by using an exon skipping approach. QR-421a is intended to be administered through intravitreal injections in the eye and has been granted orphan drug designation in the US and the European Union and received fast-track and rare pediatric disease designations from the FDA.

About ProQR

ProQR Therapeutics is dedicated to changing lives through the creation of transformative RNA therapies for the treatment of severe genetic rare diseases such as Leber congenital amaurosis 10, Usher syndrome and retinitis pigmentosa. Based on our unique proprietary RNA repair platform technologies we are growing our pipeline with patients and loved ones in mind.
Learn more about ProQR at www.proqr.com.

SOURCE: ProQR