A Systematic Literature Review of Disease Progression Reported in RPGR-associated X-linked Retinitis Pigmentosa

Abstract Purpose: RPGR -associated X-linked retinitis pigmentosa ( RPGR -XLRP) is a rare and severe form of retinitis pigmentosa (RP) resulting in progressive visual impairment; however, disease progression data are limited. A systematic literature review was conducted to assess available data on disease progression in RPGR -XLRP. Methods: PubMed, EMBASE, and select congress abstracts were evaluated through June 2022. Eligible studies included results specific to RPGR -XLRP or populations with ≥80% of RP patients carrying disease-causing RPGR variants. Endpoints of interest included visual acuity (VA), visual field (VF), ellipsoid zone width (EZW), progression to blindness, and patient-reported outcomes (PROs). Results: Fourteen studies met ≥1 endpoint of interest. Progressive declines in VA, VF, and EZW were reported across studies. Nearly all publications reported annual declines in VA (3.5%-8.2%). Annual VF declines ranged from 4.2% to 13.3%. Changes in retinal structure were also observed (EZW changes: –177 to –830 μm/y). Most studies measured blindness using VA; VF-based definitions resulted in blindness by age ∼25 years. PRO data were limited. Conclusion: Published evidence shows that patients with RPGR -XLRP experience progressive decline in VA, VF, and EZW, eventually resulting in blindness. Additional longitudinal data with standardized endpoints and expanded collection of PROs are needed to assess visual decline in RPGR -XLRP

A SYSTEMATIC LITERATURE REVIEW OF DISEASE PROGRESSION REPORTED IN RPGR -ASSOCIATED X-LINKED RETINITIS PIGMENTOSA

Retinitis pigmentosa GTPase regulator-associated X-linked retinitis pigmentosa ( RPGR -associated XLRP) is a rare and severe form of retinitis pigmentosa, resulting in progressive visual impairment; however, disease progression data are limited. A systematic literature review was conducted to assess available data on disease progression in RPGR -associated XLRP. PubMed, Embase, and select congress abstracts were evaluated through June 2022. Eligible studies included results specific to RPGR -associated XLRP or populations with ≥80% of patients with retinitis pigmentosa carrying disease-causing RPGR variants. End points of interest included visual acuity, visual field, ellipsoid zone width, progression to blindness, and patient-reported outcomes. Fourteen studies met ≥1 end point of interest. Progressive declines in visual acuity, visual field, and ellipsoid zone width were reported across studies. Nearly all publications reported annual declines in visual acuity (3.5%-8.2%). Annual visual field declines ranged from 4.2% to 13.3%. Changes in retinal structure were also observed (ellipsoid zone width changes: -177 to -830 µ m/year). Most studies measured blindness using visual acuity; visual field-based definitions resulted in blindness by age ∼25 years. Patient-reported outcome data were limited. Published evidence shows that patients with RPGR -associated XLRP experience progressive decline in visual acuity, visual field, and ellipsoid zone width, eventually resulting in blindness. Additional longitudinal data with standardized end points and expanded collection of patient-reported outcomes are needed to assess visual decline in RPGR -associated XLRP