The impact of cancer drug wastage on economic evaluations

Abstract

BACKGROUND: The objective of this study was to determine the impact of modeling cancer drug wastage in economic evaluations because wastage can result from single-dose vials on account of body surface area- or weight-based dosing. METHODS: Intravenous chemotherapy drugs were identified from the pan-Canadian Oncology Drug Review (pCODR) program as of January 2015. Economic evaluations performed by drug manufacturers and pCODR were reviewed. Cost-effectiveness analyses and budget impact analyses were conducted for no-wastage and maximum-wastage scenarios (ie, the entire unused portion of the vial was discarded at each infusion). Sensitivity analyses were performed for a range of body surface areas and weights. RESULTS: Twelve drugs used for 17 indications were analyzed. Wastage was reported (ie, assumptions were explicit) in 71% of the models and was incorporated into 53% by manufacturers; this resulted in a mean incremental cost-effectiveness ratio increase of 6.1% (range, 1.3%-14.6%). pCODR reported and incorporated wastage for 59% of the models, and this resulted in a mean incremental cost-effectiveness ratio increase of 15.0% (range, 2.6%-48.2%). In the maximum-wastage scenario, there was a mean increase in the incremental cost-effectiveness ratio of 24.0% (range, 0.0%-97.2%), a mean increase in the 3-year total incremental budget costs of 26.0% (range, 0.0%-83.1%), and an increase in the 3-year total incremental drug budget cost of approximately CaD $102 million nationally. Changing the mean body surface area or body weight caused 45% of the drugs to have a change in the vial size and/or quantity, and this resulted in increased drug costs. CONCLUSIONS: Cancer drug wastage can increase drug costs but is not uniformly modeled in economic evaluations. Cancer 2017;123:3583-90. © 2017 American Cancer Society.