Cost-effectiveness of pegaptanib compared to photodynamic therapy with verteporfin and to standard care in the treatment of subfoveal wet age-related macular degeneration in Canada

Abstract

Background: Age-related macular degeneration (AMD) is characterized by loss of central vision and is the leading cause of blindness among persons over the age of 50 years in Canada. The wet form of AMD has 3 subtypes-occult, minimally classic, and predominantly classic. Photodynamic therapy (PDT) with verteporfin is indicated only for the category of predominantly classic wet AMD. Currently, there are no treatments available for the other AMD subtypes. Pegaptanib sodium was the first pharmacologic therapy approved in Canada for the treatment of subfoveal wet AMD regardless of subtype.

Objective: The aim of this study was to examine the cost-effectiveness of pegaptanib versus PDT with verteporfin and versus standard care for the treatment of subfoveal wet AMD in patients aged 65 years in Canada.

Methods: A Markov model based on visual acuity in the better-seeing eye was developed. Clinical efficacy was taken from the clinical trials. Costs of treatment, comorbidities (eg, depression, fractures, need for assisted living), vision rehabilitation, visual aids, and adverse events were considered. Costs, utilities, and mortality were estimated from data from the available published literature. Costs were reported in 2004 Canadian dollars, and costs and outcomes were discounted at 3% per annum. Lifetime costs, quality-adjusted life-years (QALYs), and vision years gained (VYGs) were estimated. Sensitivity analyses were performed to determine model robustness.

Results: Patients who received pegaptanib experienced more QALYs gained (4.17) and VYGs (3.83) compared with patients who received PDT (3.87 and 3.01, respectively) or standard care (3.96 and 3.26). Mean total costs per patient were greater in patients who received pegaptanib compared to those who received PDT or standard care ($20,016 vs $15,345 or $7669, respectively). The incremental cost per QALY in patients receiving pegaptanib compared to those receiving PDT was $49,052 and $59,039 for patients receiving pegaptanib versus standard care. The incremental cost per VYG was $20,401 and $21,559 with pegaptanib versus PDT and standard care, respectively. Sensitivity analyses found that the model was relatively robust to changes in various model parameters.

Conclusion: The results of this analysis suggest that in Canada, pegaptanib is a cost-effective treatment for subfoveal wet AMD in elderly patients, regardless of lesion subtype, compared to PDT with verteporfin and to standard care.