This Phase 1/2 study will gather data in an observational phase Natural History Cohort to further characterize and evaluate natural disease progression in male patients with genetically-confirmed X-linked retinitis pigmentosa (XLRP) caused by mutations in the gene encoding retinitis pigmentosa GTPase regulator (RPGR). The study will also evaluate the safety and tolerability, as assessed by frequency and severity of ocular and systemic adverse events, as well as preliminary clinical efficacy of a single intravitreal (IVT) injection of 4D-125 at two dose levels in this patient population in one or both eyes (the contralateral eye dose provided the subject is eligible and provides consent).
4D-125 has been developed as a gene replacement therapy for XLRP. After receiving 4D-125, patients will be followed for 24 months with continued safety follow-up and 36 additional months of long-term follow-up. Secondary endpoints will assess preliminary efficacy measures over time after 4D-125 administration.
