Press Release

Disclosures: Koenekoop reports no relevant financial disclosures.
March 24, 2021
1 min read

ProQR announces positive phase 1/2 study data for Usher syndrome candidate


Press Release

Disclosures: Koenekoop reports no relevant financial disclosures.
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ProQR Therapeutics released positive results from its phase 1/2 Stellar trial investigating QR-421a in patients with Usher syndrome and non-syndromic retinitis pigmentosa, according to a press release.

The therapy was well tolerated at all doses, and patients did not have any serious adverse events or inflammation, the release said.

Stellar, a randomized, sham-controlled, single ascending dose, global, multicenter study, included 20 subjects, 14 who received a single dose of QR-421a and six who received a single sham procedure for masking. Patients were organized into advanced and early-moderate disease state populations based on baseline visual acuity, and three dose levels were studied.

After one injection, a mean increase of 6 ETDRS letters was observed at week 48 in all treated eyes compared with untreated contralateral eyes. Among the six patients with advanced disease, an increase of 9.3 letters was observed at 48 weeks and maintained for more than 12 months compared with no eyes in the sham group having a benefit, the release said.

"Previously, inherited retinal disease patients were told there is no treatment. Nothing can be done to slow, stop or improve their declining vision. Now we have these very strong safety and efficacy data from the QR-421a study (and other studies) that show that IRDs are in part safely treatable,” Robert Koenekoop, MD, PhD, of Montreal Children’s Hospital and professor at McGill University Faculty of Medicine and Department of Pediatric Surgery, told Healio/OSN.

Static perimetry measurements showed a mean total retinal sensitivity of 40 dB higher in treated eyes compared with untreated eyes, and the increase was maintained for more than 6 months, the release said.

ProQR plans to initiate two pivotal phase 2/3 trials by the end of the year, one in early-moderate patients and one in advanced patients, the release said.

Editor’s Note: On March 29, 2021, this article was updated to include comments from Robert Koenekoop, MD, PhD.