Verteporfin photodynamic therapy for neovascular age-related ...

DOI: 10.3310/hta16060Health Technology Assessment 2012; Vol. 16: No. 645Chapter 6Results (2) – objectives A, B, C and DA: Is verteporfin photodynamic therapy in the NHS provided as inrandomised trials?The analysis for objective A focused on provision of VPDT in the year following the firsttreatment. Given that TAP trials required prospective participants to have CNV from nAMD, theanalysis was based on only the subgroup of patients with CNV from nAMD who were classifiedas having completed their treatment (n = 4043), with one eye per patient.Is treatment administered at the same frequency as in the randomised trials?The numbers of VPDT treatments administered in years 1 and 2 by TAP eligibility status (i.e.groups EFT, IFT and UNC) are shown in Tables 10 and 11. In year 1 of the VPDT cohort study(≤ 350 days after the first treatment), fewer treatments were administered (average 2.35) thanin year 1 in the TAP trials (average 3.4). We compared the numbers of patients having one,two, three and four treatments in year 1 in the VPDT cohort study and in the TAP trials, whichdiffered significantly (χ 2 = 615.2, degrees of freedom 4, p < 0.0001). 4,30 The average number oftreatments for each of the TAP eligibility groups in the VPDT cohort study was EFT 2.47, IFT2.31 and UNC, 2.29. The numbers of patients having one, two, three and four treatments in year 1also differed significantly between groups (χ 2 = 364.3, degrees of freedom 8, p < 0.0001).When considering treatment frequencies in year 2, we had data on 1611 patients who hadcompleted treatment for year 2 of study (see Chapter 4, Definition of year 1 and year 2). Theaverage number of treatments administered to these patients was 0.40, compared with 2.2 in theTAP trials. In year 2, the numbers of treatments administered cannot be compared because thedistribution of treatments in the TAP trials in year 2 was not reported. The average number oftreatments for each of the TAP eligibility groups was EFT 0.40, IFT 0.37 and UNC, 0.43. Unlikeyear 1, the numbers of patients having one, two, three and four treatments in year 2 did not differsignificantly between groups (χ 2 = 6.62, degrees of freedom 6, p = 0.36).Is treatment duration the same as in the randomised trials?As described in Chapter 3, Data collection and management, the VPDT manual of operationsset out a schedule for follow-up and retreatment. This schedule was intended to approximatethe follow-up and retreatment guidance provided in the TAP trials, that is patients should beexpected to be observed over a period of 2 years with retreatment every 3 months if required.The treatment frequencies described in Is treatment administered at the same frequency as in therandomised trials? show that much less treatment was administered in the study than would havebeen expected on the basis of the TAP trials.Based on our definition of a completed treatment episode (see Chapter 4, Classification oftreatment as active or completed), we constructed a Kaplan–Meier curve describing ‘survival’until completion of the treatment episode for the 4566 patients who had data for one eye startingtreatment > 350 days before the close of the study, shown in Figure 6. This figure shows thatjust over 50% of eyes completed the treatment episode in < 1 year. Thus, not only were fewertreatments administered in the study than in the TAP trials, but also the duration of review ofpatients’ CNV status was shorter than in the TAP trials for the majority of treatment episodes.© 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.