Verteporfin photodynamic therapy for neovascular age-related ...

DOI: 10.3310/hta16060Health Technology Assessment 2012; Vol. 16: No. 665Chapter 8Discussion of resultsThe VPDT cohort study broke new ground in that it was a publicly funded postlicensing studyof an expensive new technology that was beneficial in the management of subfoveal nAMD.Previously, this condition had been largely untreatable. The technology involved the use of thedrug verteporfin (a photosensitiser) and its activation within the eye with an infrared nonthermallaser (thus avoiding direct physical injury to the neural retina). Its application to routinepractice necessitated significant investment in expensive equipment and dissemination of newknowledge to ophthalmologists in the interpretation of retinal imaging outputs for diagnosis,case selection, treatment initiation and retreatment decision-making.Although the appraisal by NICE found the treatment to be clinically effective, there was arecognition that evidence about its cost-effectiveness was based on multiple assumptions whichwere not robust. Hence, the Department of Health recommended a limited and managedintroduction of this technology with collection of robust visual function and resource utilisationdata to assess whether or not its clinical effectiveness and cost-effectiveness matched thoseobserved in the licensing trials; it was also recommended that a measure of its impact on HRQoLshould be obtained.Thus, the size and the scope of the VPDT study was far more extensive than any previous studyof nAMD and acted as a treatment registry containing data acquired on patients receiving VPDTin the clinical sites that were selected to provide VPDT. Protocol-based BCVA and CS weremeasured at multiple time points and HRQoL instruments were administered to patients at abouthalf of the clinical sites. Collection of these data made it possible to investigate relationshipsbetween clinical measures of vision and HRQoL as continuous scales (in contrast to manyprevious studies).Key findingsThe key findings from the VPDT cohort study are outlined below:■■■■■■■■■■The change in BCVA was similar to that observed in the treatment groups in the pivotallicensing trials, although the deterioration in BCVA over time may have been underestimated(see Strengths and weaknesses of the verteporfin photodynamic therapy cohort study).The BCVA benefit was achieved with fewer treatments.In addition, non-treatment-related baseline covariates influenced change in BCVA over thestudy period.In the better-seeing eye, BCVA and CS were highly significant predictors of SF-6D utility,SF-36 component scores and NEIVFQ scores. The change in utility for a unit change inBCVA was less than several previous estimates.Realistic estimates of the cost-effectiveness of VPDT were obtained and were consistent withhigher previous estimates, although these high estimates are almost certainly too low becauseof the assumption (common to all CEAs) that the better-seeing eye is being treated.© Queen’s Printer and Controller of HMSO 2012. This work was produced by Reeves et al. under the terms of a commissioning contract issued by theSecretary of State for Health.