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Verteporfin photodynamic therapy for neovascular age-related ...

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DOI: 10.3310/hta16060Health Technology Assessment 2012; Vol. 16: No. 6952. Introduction2.1 <strong>Verteporfin</strong> <strong>photodynamic</strong> <strong>therapy</strong> (PDT) <strong>for</strong> the treatment of choroidal<strong>neovascular</strong>isation (CNV) of the eyeChoroidal <strong>neovascular</strong>isation (CNV) is the hallmark of the condition known asexudative <strong>age</strong>-<strong>related</strong> macular degeneration (AMD) of the eye. The untreated naturalhistory of CNV is one of relentless vision loss culminating in central visual impairmentof varying severity. This loss interferes with daily tasks such as reading, driving,watching television and recognising peoples’ faces and frequently results in loss ofindependent living.When CNV is subfoveal (that is, when CNV is under the centre of the fovea, the partof the retina that allows people to see fine detail), it is not amenable to thermal laserphotocoagulation, a <strong>for</strong>m of <strong>therapy</strong> that has been the mainstay of man<strong>age</strong>ment <strong>for</strong>many years. None of the treatments tested in recent years have been shown toimprove vision once it is lost, nor have there been treatments that consistentlyprevent additional decline in vision from the time of their application.Because the visual impairment caused by vision loss from exudative AMD is sosevere, it is now accepted that treatments which are only partly effective maynevertheless yield important visual, quality of life and economic benefits. Recently atreatment called verteporfin <strong>photodynamic</strong> <strong>therapy</strong> (PDT) has been shown toresult in a better outcome when compared with the natural history of CNV patientswho did not receive PDT. In the randomised controlled clinical trial the "Treatment ofAge-<strong>related</strong> macular degeneration by Photodynamic <strong>therapy</strong> (TAP) study", eyes withCNV exposed to laser irradiation following systemic infusion of the drug verteporfinwere more likely to have maintained visual function when compared with patients withsimilar CNV who received placebo followed by similar irradiation [1]. The treatmentworks because the drug verteporfin is internalised by the vascular endothelium. Lightactivation of the drug results in the release of free radicals that dam<strong>age</strong> endotheliumand adjacent tissues and cells. By targeting a low energy laser into the region of theCNV, the endothelium of the aberrant blood vessels may be selectively irradiated,causing focal dam<strong>age</strong> to the vessel wall and closure of the vessels comprising theCNV.2.2 NICE Guidance on <strong>Verteporfin</strong> PDT<strong>Verteporfin</strong> PDT was referred in 2000 <strong>for</strong> appraisal by the National Institute of ClinicalExcellence (NICE) [2], which reviewed available evidence. In the TAP trial, 15%© 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 <strong>for</strong> Health.

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