Cost-Effectiveness of Tenofovir Alafenamide for Treatment of Chronic Hepatitis B in Canada.

Abstract

Tenofovir alafenamide (TAF) has been approved for treating chronic hepatitis B (CHB) due to a proposed better safety profile in comparison with current therapies. We evaluated the cost effectiveness of TAF and other available treatment options for hepatitis B envelope antigen (HBeAg)-positive and HBeAg-negative CHB patients from a Canadian provincial Ministry of Health perspective. A state-transition model based on the published literature was developed to compare treatment strategies involving entecavir (ETV), tenofovir disoproxil fumarate (TDF), and TAF. It adopted a lifetime time horizon. Outcomes measured were predicted number of liver-related deaths, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs). For HBeAg-positive patients, TAF followed by ETV generated an additional 0.16 QALYs/person at an additional cost of Can$14,836.18 with an ICER of Can$94,142.71/QALY compared with TDF followed by ETV. Of the iterations, 28.7% showed that it is the optimal strategy with a Can$50,000 willingness-to-pay threshold. For HBeAg-negative patients, ETV followed by TAF would prevent an additional 13 liver-related deaths per 1000 CHB patients compared with TDF, followed by ETV. It generated an additional 0.13 QALYs/person at an additional cost of Can$59,776.53 with an ICER of Can$461,162.21/QALY compared with TDF, followed by ETV. TAF-containing strategies are unlikely to be a rational choice in either case. The results were sensitive to the HBeAg seroconversion rates and viral suppression rates of the treatments. Our analysis suggests that TAF is not cost effective at its current cost. A 33.4% reduction in price would be required to make it cost effective for HBeAg-positive patients with a Can$50,000 willingness-to-pay threshold.