Retinitis Pigmentosa: Burden of Disease and Current Unmet Needs

Abstract

Retinitis Pigmentosa (RP), a group of inherited retinal dystrophies characterised by progressive vision loss, is the leading cause of visual disability and blindness in subjects less than 60 years old. Currently incurable, therapy is aimed at restricting degeneration of vision, treating complications, and helping patients to cope with the psychosocial impact of their disease. Hence, RP is associated with a high burden of disease. This paper describes the current therapeutic landscape for RP and the disease burden for patients, caregivers, and society. A review of available data was conducted in three stages: (1) a literature search of publicly available information on all domains of RP; (2) a systematic literature review using Medline, Embase, the Cochrane Library and grey literature (GlobalData) on epidemiology and cost of RP; and (3) qualitative research with senior physicians treating RP patients in the EU4 and the UK to validate research findings from secondary sources. RP severely impacts the daily lives of over a million people worldwide. Progressive vision loss significantly affects the ability to perform basic daily tasks, to maintain employment, and maintain independence. Consequently, most patients will experience reduced quality of life, with a greater emotional and psychological impact than other conditions related to vision loss such as diabetic retinopathy or age-related macular degeneration. RP is also associated with a high level of carer burden, arising from psychological and financial stress. The therapeutic landscape for RP is limited, with few treatment options and minimal guidance for the diagnosis, treatment, and care of patients. A curative intervention, voretigene neparvovec (Luxturna^®), only exists for 1-6% of patients. Although disease management can be successful in developing coping strategies, most patients live with this chronic, progressive condition without interventions to change the disease course. Innovative new therapies can transform the therapeutic landscape, provided appropriate clinical guidance is forthcoming.

Keywords: burden of disease; retinal dystrophy; retinitis pigmentosa; treatment; visual impairment.

Figure 1

Identification of studies on the epidemiology of RP. Created using the official PRISMA 2020 flow diagram for new systematic reviews.

Figure 2

Identification of studies on the cost of RP. Created using the official PRISMA 2020 flow diagram for new systematic reviews.

Figure 3

Classification of inheritance type of RP from a cohort of Spanish patients. Data from Perea- Romero et al.

Figure 4

Suggested mechanisms contributing to the death of cone photoreceptors in RP. Data from Narayan et al.

Figure 5

RP diagnosis age based on the onset of symptoms, split by genotype. Data from these studies.,

Figure 6

Progression of disease in patient with autosomal dominant RP. Top: representation of visual field; bottom: images from fundus photography; from left to right: progressing from normal visual field in a patient in teenage years (first column) to severely constricted visual field in a patient over 50 years (sixth column). Fundus images show the progression of vessel attenuation and retinal pigment epithelium atrophy, as well as sharp demarcation lines (arrow) between the healthy and affected retina.

Figure 7

Referral pathway for patients with RP.  Data from Lightning Health. European ophthalmologist research; 2021.

Figure 8

Employment rates across groups with different levels of visual impairment France. Data from Chaumet-Riffaud et al.