The Value of Evidence in the Decision-Making Process for Reimbursement of Pharmacogenetic Dosing of Warfarin

Background After early clinical trials that evaluated pharmacogenetic (PG) algorithms, many healthcare payers were reluctant to cover this technology and, consequently, PG dosing of warfarin could not be translated into clinical practice. Objective The aim of this study was to estimate the value of upgrading evidence relating to PG dosing of warfarin from the healthcare payer perspective. Methods Randomized controlled trials (RCTs) that evaluated PG dosing of warfarin were identified through a systematic literature search, and their findings were combined by a cumulative meta-analysis. A health economic model was used to estimate economic outcomes and to calculate the expected value of perfect information (EVPI) as a measure of the value of clinical trials for decision makers. Results Nine RCTs were identified and included in our analysis. The estimated difference in the percentage of time in the therapeutic range was 5.6 percentage points in 2007, decreasing to 4.3 percentage points when all studies were included. At a reimbursement price of €160 per PG testing, the EVPI for the clinical benefit was estimated at €80 and €90 per patient in 2007 and 2014, respectively. A reduction in the price of PG testing to €40, which was observed in this period, resulted in an EVPI of €3 per patient. Conclusions The estimated cumulative effect of PG dosing has remained similar since 2007, but additional evidence has contributed to a more precise estimation. While these variations should not affect the reimbursement decision, a large decline in the cost of PG testing in recent years calls for reconsideration.