Preferences for Adjuvant Immunotherapy in Adults with Resected Stage III Melanoma—A Discrete Choice Experiment

Objectives: This study aimed to quantify adult preferences for adjuvant immunotherapy for resected melanoma and the influence of varying levels of key attributes and baseline characteristics. Methods: A D-efficient design generated 12 choice tasks for two alternative treatments, adjuvant immunotherapy or no adjuvant immunotherapy. Recruitment to the online discrete choice experiment (DCE) occurred via survey dissemination by eight Australian melanoma consumer and professional groups, targeting adults with resected stage III melanoma, considering or having received adjuvant immunotherapy. The DCE included six attributes with two to three levels each, including 3-year risk of recurrence, mild, permanent and fatal adverse events (AEs), drug regimen and annual out-of-pocket costs. A mixed multinomial logit model was used to estimate preferences and calculate marginal rates of substitution and marginal willingness to pay (mWTP). Results: The DCE was completed by 116 respondents, who chose adjuvant immunotherapy over no adjuvant immunotherapy in 70% of choice tasks. Respondents preferred adjuvant immunotherapy when associated with reduced: probabilities of recurrence, permanent and fatal AEs, and out-of-pocket costs. mWTP for an absolute reduction of 1% in 3-year risk of recurrence was less for respondents with lower rather than higher incomes, AU$794 (US$527) and AU$2190 (US$1454) per year. Respondents accepted an additional 4% chance of a permanent AE to reduce their absolute risk of 3-year recurrence by 1%. Respondents were willing to accept an extra 2% chance of 3-year recurrence to lower their chance of a fatal AE by 1%. Conclusions: Almost three-quarters of respondents chose adjuvant immunotherapy over no adjuvant immunotherapy, preferring treatment that improved efficacy and safety. Findings may inform decisions about access to adjuvant immunotherapy following surgery for melanoma.