Abstract
BACKGROUND: Economic evaluation helps policy makers and healthcare payers make decisions on drug listing, coverage, and reimbursement. When economic evaluations are conducted before a product launch, the prices of the pharmaceuticals have to be forecast. OBJECTIVE: The aim of this study was to examine the methods of establishing proxy prices and their accuracies compared with actual market prices after the product launch. METHODS: We searched the literature for evaluations for drugs that were licensed in the US between 2010 and 2015. We reviewed the studies for the forecasting strategies used, and then estimated the difference between actual 2016 post-launch prices and what the proxy prices would be if the forecast was carried out in the US in 2016. RESULTS: We identified six such studies, with seven drugs. Four studies used substitute drugs as proxies for the study drug, and three used other methods. The range of the values of actual minus proxy price varied considerably, and no trend was observed. CONCLUSION: Forecasting drug prices is as precarious as forecasting in other areas of the economy. We urge caution in reviewing and accepting a cost-effectiveness ratio that is based on forecast prices.