Accounting for Cured Patients in Cost-Effectiveness Analysis.

Publication Type:

Journal Article

Source:

Value in health : the journal of the International Society for Pharmacoeconomics and Outcomes Research, Volume 20, Issue 4, p.705-709 (2017)

Keywords:

Adult, Aged, Aged, 80 and over, Antibodies, Monoclonal, Antineoplastic Agents, Bias (Epidemiology), Cost-Benefit Analysis, Drug Costs, Female, GLYCOPROTEINS, Humans, Kaplan-Meier Estimate, Male, MELANOMA, Middle Aged, Models, Economic, Quality-Adjusted Life Years, Randomized Controlled Trials as Topic, Remission Induction, Skin Neoplasms, Survivors, Time Factors, Treatment Outcome, Young Adult

Abstract:

BACKGROUND: Economic evaluations often measure an intervention effect with mean overall survival (OS). Emerging types of cancer treatments offer the possibility of being "cured" in that patients can become long-term survivors whose risk of death is the same as that of a disease-free person. Describing cured and noncured patients with one shared mean value may provide a biased assessment of a therapy with a cured proportion.

OBJECTIVE: The purpose of this article is to explain how to incorporate the heterogeneity from cured patients into health economic evaluation.

METHODS: We analyzed clinical trial data from patients with advanced melanoma treated with ipilimumab (Ipi; n = 137) versus glycoprotein 100 (gp100; n = 136) with statistical methodology for mixture cure models. Both cured and noncured patients were subject to background mortality not related to cancer.

RESULTS: When ignoring cured proportions, we found that patients treated with Ipi had an estimated mean OS that was 8 months longer than that of patients treated with gp100. Cure model analysis showed that the cured proportion drove this difference, with 21% cured on Ipi versus 6% cured on gp100. The mean OS among the noncured cohort patients was 10 and 9 months with Ipi and gp100, respectively. The mean OS among cured patients was 26 years on both arms. When ignoring cured proportions, we found that the incremental cost-effectiveness ratio (ICER) when comparing Ipi with gp100 was $324,000/quality-adjusted life-year (QALY) (95% confidence interval $254,000-$600,000). With a mixture cure model, the ICER when comparing Ipi with gp100 was $113,000/QALY (95% confidence interval $101,000-$154,000).

CONCLUSIONS: This analysis supports using cure modeling in health economic evaluation in advanced melanoma. When a proportion of patients may be long-term survivors, using cure models may reduce bias in OS estimates and provide more accurate estimates of health economic measures, including QALYs and ICERs.