An Open-Label Extension Study to Evaluate Safety & Tolerability of QR-421a in Subjects With Retinitis Pigmentosa

PQ-421a-002 is an open-label, extension study to evaluate the safety, tolerability and efficacy of QR-421a (ultevursen) in subjects with RP due to mutations in exon 13 of the USH2A gene. Subjects that have participated in QR-421a clinical studies, i.e. PQ-421a-001 (Stellar), PQ-421a-003 (Sirius) and PQ-421a-004 (Celeste), will be given the opportunity to enroll into this extension study for continued dosing, provided the subject's benefit-risk assessment is positive, or for additional follow up. The Investigator, in consultation and agreement with the Medical Monitor, will decide on subject's enrollment upon assessment of subject's benefit-risk. QR-421a will be first administered to the Contralateral Eye (CE or fellow eye), as defined in the preceding study, and will be repeated every 6 months. Administration of QR-421a to the Treatment Eye (TE or study eye), as defined in the preceding study, can commence 3 months (9 months for subjects from study PQ-421a-001) after the treatment of the contralateral eye has been initiated and will be repeated every 6 months as well. The Investigator, in consultation and agreement with the Medical Monitor, will decide on dosing of both eyes. Continued subject treatment in this study will be pursued provided that the benefit-risk balance is positive for the individual subject, as discussed and agreed upon with the Medical Monitor. The same safety monitoring protocol and efficacy assessments will apply to both eyes. Baseline functional and structural measurements for the treatment eye will be those from the preceding QR-421a study. Baseline functional and structural measurements for the contralateral eye will be those from the Screening /Day 1 visit of the current study.