Gene therapy and the adeno associated virus in the treatment of genetic and acquired ophthalmic diseases in humans: trials, future directions and safety considerations

Voretigene neparvovec-rzyl was recently approved for the treatment of Leber Congenital Amaurosis, and the use of gene therapy for eye disease is attracting even greater interest. The eye has immune privileged status, is easily accessible, requires a reduced dosage of therapy due to its size, and is highly compartmentalized, significantly reducing systemic spread. Adeno-associated virus (AAV), with its low pathogenicity, prolonged expression profile and ability to transduce multiple cell types, has become the leading gene therapy vector. Target diseases have moved beyond currently untreatable inherited dystrophies to common, partially treatable acquired conditions such as exudative AMD and glaucoma, but use of the technology in these conditions imposes added obligations for caution in vector design. This review discusses the current status of AAV gene therapy trials in genetic and acquired ocular diseases, and explores new scientific developments which could help ensure effective and safe use of the therapy in the future

Willingness to pay for genetic testing for inherited retinal disease

This paper investigates the willingness of adults with inherited retinal disease to undergo and pay for diagnostic genetic testing in three hypothetical scenarios and to explore the factors that influence decision making. Fifty patients were presented with three scenarios whereby genetic testing provided increasing information: confirming the diagnosis and inheritance pattern alone, providing additional information on future visual function, and identifying in addition a new treatment which could stabilise their condition. Willingness to pay (WTP) was elicited using an iterative bidding game. Regression analysis was used to investigate the probability of agreeing to and paying for testing. Qualitative data were also reviewed to provide a comprehensive understanding of WTP and decision making. The majority of participants agreed to undergo genetic testing in each of the three scenarios. Scenario 2 was the least acceptable with 78% of participants agreeing to genetic testing. The probability of agreeing to genetic testing decreased with age. Between 72 and 96% of participants reported a WTP for genetic testing. Average WTP was £539, £1516, and £6895 for scenarios 1, 2, and 3 respectively. Older participants and participants with higher incomes were willing to pay more for testing. Qualitative data provided additional detail about the rationale behind participants’ decisions. The study suggests that patients with inherited retinal disease were willing to undergo and to pay for diagnostic genetic testing, suggesting that they valued the information it may provide. However, several patients preferred not to receive prognostic information and were less willing to pay for genetic testing that yielded such detail