A pilot study to evaluate the feasibility of using willingness to pay as a measure of value in cancer supportive care: an assessment of amifostine cytoprotection

Abstract

 The most commonly used method for pharmacoeconomic studies has been the cost-effectiveness analysis (CEA), where the outcome is expressed as an incremental cost per unit of effectiveness (e.g. quality-adjusted life years). Although CEA is a valuable tool for identifying therapies that are more effective and less expensive, deficiencies develop when a given treatment is both more expensive and more effective. An alternative that has not been investigated in the oncology setting is the willingness-to-pay (WTP) method. In this pilot study, a WTP strategy was utilized to estimate the value that the Canadian tax-paying public puts on amifostine, a new cytoprotective agent that reduces the risk of chemotherapy-induced toxicity. The method of WTP was used within the framework of a classical cost–benefit analysis to estimate the net cost or benefit of prophylactic amifostine in patients with ovarian cancer who were receiving chemotherapy. This included direct costs for amifostine administration and hospital savings secondary to the reduced incidence of antineoplastic toxicity. A random sample of 50 Canadian taxpayers were interviewed to ascertain their maximum WTP for the new drug. The WTP survey instrument was simple to administer and easily understood by participants. Respondents stated that they would be willing to pay an average of $Can3,476 (95% confidence interval=$Can2,275 to $Can4,676) as an income tax increase to be paid over their lifetime for the value offered by the product. The benefit was then subtracted from the overall cost of amifostine ($Can3,826). This produced a net cost of $Can350 per patient (95% confidence interval=–$Can850 to $Can1,551), suggesting a situation of cost neutrality. WTP as a measure of value for oncology products is feasible and should be considered for future economic evaluations. The strategy is currently being used at this institution to determine the net societal cost or benefit of other cancer supportive care therapies, such as epoetin-alfa.