A systematic literature review of disease progression in RPGR‐associated X‐linked retinitis pigmentosa

Abstract

AbstractPurpose: To assess disease progression qualitatively and quantitatively in RPGR‐associated X‐linked retinitis pigmentosa (RPGR‐XLRP).Methods: PubMed was used to identify relevant studies (01/2000–09/2021). Search terms included RP, XLRP, history, progress, disease state, health state, and burden. Included studies focused on RPGR‐XLRP (ie, results specific to RPGR or RP studies with ≥80% of patients with RPGR variants). Endpoints of interest included changes in visual acuity (VA), visual field (VF), and ellipsoid zone width (EZW), progression to legal blindness, and patient‐reported outcomes (PROs).Results: Of 1325 studies captured by search criteria (including those examining XLRP [n = 17], RP [127], and both XLRP and RP [6]), 11 met inclusion criteria for assessment of RPGR‐XLRP disease progression. In those with RPGR‐XLRP, data suggest progressive decline in VA, VF, and EZW. Annual changes in VA were equivocal, with two studies reporting positive or minimal change in best‐corrected VA (BCVA; +2%, −0.07%) and two studies reporting VA decline (−3.5 to −5.3%, −8.2%). Annual declines in VF, measured via Goldmann or Humphrey perimetry, were observed across studies (range, −4.5, −9.0%; n = 4 studies). EZW, measured via Heidelberg Spectralis OCT, became constricted over time (n = 5 studies); 2 studies showed an 8%–9% annual exponential rate of decline. In two studies, patients reached VA‐based legal blindness (BCVA <20/400 in the better seeing eye or <6/60) by median ages of 48 and 51.3 years; in another study, 18% reached blindness (BCVA <20/400) by age 40. PRO data in this patient population were limited.Conclusions: Published evidence shows that those with RPGR‐XLRP experience significant progressive decline in VA, VF, and EZW, eventually resulting in blindness. There is a need for more standardized longitudinal data and expanded collection of PROs to better assess visual decline in RPGR‐XLRP.