Verteporfin photodynamic therapy for neovascular age-related ...

74 Discussion of resultsVPDT. It is important for future CEAs to assess the proportion of worse-seeing eyes that presentfor treatment in routine practice. We did not incorporate the proportion from the cohort studybecause it will almost certainly have changed over time as treatments and referral pathways fornAMD became more established.Implications for practiceThe main implications do not relate to the use of VPDT to treat nAMD because VPDT hasnow been superseded by the introduction of new treatments (see Current status of verteporfinphotodynamic therapy and future research).■■■■■■■■■■The fact that a much smaller number of treatments was administered than in the TAP trialssuggests that treatment regimens receiving marketing authorisation may overestimate theintensity of treatment required. This observation may apply to other new health technologies.Our ability to estimate effectiveness was limited by substantial loss to follow-up, whichprevented comparisons with outcomes in RCTs and a systematic review of RCTs. Thislimitation should be carefully considered in the design of similar future studies if theeffectiveness of an intervention is not dramatic and treatment or follow-up is scheduled overmany months (conditions which we suspect may cause clinicians or patients not to adhere tothe treatment regimen).Verteporfin photodynamic therapy is less effective than newer technologies in treatingnAMD. Its use should be limited to circumstances in which these newer technologiesare contraindicated or refused by patients, and to categories of AMD such as polypoidalchoroidopathy or other diseases with neovascularisation arising from the choroid, forexample high myopia.Licensing trials generally involve only one eye, and the benefit to a person from effectivetreatment for an eye will depend on whether or not the person’s visual function is limited bythe vision in the treated eye. In terms of cost-effectiveness, an appraisal of a technology thatbenefits one eye should evaluate the benefit at the level of a person, not an eye.The gradients of the relationships (a) between BCVA and EQ-5D utility and (b) betweenBCVA and HSS resource use/cost were shallower than most previous estimates. Theconsequences of these relationships for the appraisal of other technologies to treat eyediseases that impair vision need to be considered carefully.Current status of verteporfin photodynamic therapy and future researchVerteporfin photodynamic therapy as a monotherapy for nAMD has been superseded bythe introduction of molecular biologicals that target VEGF, a key molecule that promotesneovascularisation in AMD. The latter technology was introduced in 2006 followingdemonstration that monthly intravitreal injections of ranibizumab, a monoclonal antibody thatinhibits VEGF, is vastly superior to both BSC and PDT. 72,73 Anti-VEGF therapies have also beenshown to result in discernible improvements in HRQoL, outcomes which were not demonstrablewith VPDT. VPDT combined with anti-VEGF therapy has been investigated, but the resultssuggest only a marginally improved benefit in terms of fewer treatments and no benefit in termsof visual acuity for nAMD. 84Research recommendations outside the context of nAMD are:■■Benefit from VPDT has been shown for visual acuity outcomes in specific nAMD variantssuch as polypoidal choroidopathy. VPDT continues to be used as first-line treatment in the