Methylnaltrexone in the Treatment of Opioid-Induced Constipation in Cancer Patients Receiving Palliative Care: Willingness-to-Pay and Cost-Benefit Analysis

CONTEXT:When laxative regimens have failed, methylnaltrexone may be indicated for the relief of opioid-induced constipation (OIC) in patients with advanced illness receiving palliative care. OBJECTIVES:A cost-benefit analysis (CBA), based on a willingness-to-pay (WTP) approach, was performed to determine if methylnaltrexone should be added to the formulary list of drugs being reimbursed by third-party payers in Canada for the treatment of cancer patients in palliative care suffering from OIC. METHODS:The WTP study had two components: a decision board explaining treatment options (Component A) and a questionnaire to measure individual WTP using a bidding game approach (Component B). Component A had two options: Option 1 (laxatives only) and Option 2 (laxatives+methylnaltrexone injection). Only participants choosing Option 2 were invited to complete Component B. The results of the WTP survey were then incorporated into a CBA. Within a hypothetical cohort, additional monthly premiums that individuals were willing to pay for methylnaltrexone were compared with the monthly costs to the insurer for providing methylnaltrexone to all patients who would potentially be using it. RESULTS:Four hundred one Canadians, of age 18 years and older, were surveyed and yielded a WTP in additional monthly insurance premiums of Canadian dollar (CAD) $8.65 (95% confidence interval: CAD$6.17-CAD$11.13). The CBA resulted in additional CAD$89,307 with a cost of CAD$139,840 and benefits of CAD$229,147. A set of 10,000 Monte Carlo simulations resulted in average CBA savings of CAD$145,011 with a 99.86% probability of dominance. CONCLUSION:The present CBA provides pharmacoeconomic evidence for the adoption of methylnaltrexone for treating OIC in terminally ill cancer patients.