- Patients in a Phase 1/2 trial taking ProQR's experimental eye drug sepofarsen had eyesight improvements gained at three months sustained through one year, giving the company confidence that a Phase 3 trial measuring improvements at 12 months will show similar benefits.
- The patients had a rare inherited disease called Leber’s congenital amaurosis 10 (LCA10), which causes blindness in children. Spark Therapeutics' marketed gene therapy Luxturna treats a similar condition, although caused by a different mutation.
- ProQR could have competition. Allergan and Editas Medicine have initiated a Phase 1/2 trial of gene-editing agent EDIT-101, which aims to treat LCA10 patients with the same mutation that sepofarsen targets.
Sepofarsen, formerly called QR-110, treats LCA10 patients with a mutation called p.Cys998X. In that, it has a unique selling proposition next to Luxturna, which treats the LCA when caused by a mutation called RPE65.
Both mutations impede protein that help build the retina, the light-sensing tissue at the back of the eye. Broadly, LCA affects about two to three newborns per 100,000, and can be caused by mutations in up to 14 genes.
To treat LCA10, ProQR uses a similar approach to companies like Alnylam Pharmaceuticals, Ionis and Moderna Therapeutics, using oligonucleotides to bind to RNA and alter genetic expression.
The Phase 1/2 trial on which ProQR reported data today tested sepofarsen in 11 patients, with six patients receiving the dose now being used in the Phase 2/3 trial. Four of six patients in that dosing group had eyesight in their treated eye improve by three or more lines on a visual acuity chart at 12 months, which U.S. regulators regard as clinically meaningful.
This is similar to results from a three month interim analysis, which encouraged the company to design and initiate its Phase 2/3 trial aimed at a Food and Drug Administration submission.
ProQR dosed its first of 30 patients in that Phase 2/3 trial in April, and it is likely to generate results by the end of 2020.
Editas and Allergan are taking aim at the same condition with EDIT-101, a CRISPR-based gene-editing treatment delivered by an adeno-associated virus also known as AGN-151587. They have initiated a Phase 1/2 trial that will enroll 18 patients who will be given a single injection of three different doses, and then follow them for 12 months to measure safety and visual acuity improvements.
The start of that trial, announced July 25, puts Editas and Allergan more than a year behind ProQR. However, with Allergan as a partner, Editas may be in a better commercial position if ProQR can't find a bigger company to license sepofarsen or acquire it.