Tenofovir disoproxil fumarate for the treatment of chronic hepatitis B

Abstract

This paper presents a summary of the evidence review group (ERG) report into the clinical effectiveness and cost-effectiveness of tenofovir disoproxil fumarate for the treatment of chronic hepatitis B, in accordance with the licensed indication, based upon the evidence submission from Gilead to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal process. The submitted clinical evidence included two international randomised controlled trials (RCTs) comparing tenofovir with adefovir, and a mixed treatment comparison (MTC) using Bayesian methodology to compare tenofovir with other nucleos(t)ide analogues using direct and indirect RCT evidence. There were no statistically significant differences between tenofovir and adefovir in overall adverse events although, in hepatitis B 'e' antigen (HBeAg)-positive patients, there was a higher incidence of mild nausea in the tenofovir treatment group. The primary outcome, 'complete response', was a composite end point defined as histology response and hepatitis B virus DNA below 400 copies/ml. For both HBeAg-positive and HBeAg-negative patients, a significantly greater proportion had a complete response after 48 weeks with tenofovir than with adefovir. There was no statistically significant difference in histological response in either group of patients compared with adefovir. The MTC could only generate results for HBeAg positive nucleos(t)ide naive patients as there was insufficient evidence for other subgroups. The probability of achieving undetectable HBV DNA with tenofovir was found to be significantly higher than that for all other treatments considered in the analysis at the 0.05 level. The analysis demonstrated that there is a 98% probability that tenofovir is the most potent nucleos(t)ide in terms of this outcome. The manufacturer's submission concluded that tenofovir is a cost-effective option as first-line treatment. For HBeAg-positive patients, tenofovir followed by lamivudine has an incremental cost-effective ratio (ICER) of 9940 pounds per quality-adjusted life-year (QALY) gained, compared with lamivudine followed by tenofovir. A more appropriate treatment strategy of tenofovir followed by tenofovir plus lamivudine has an ICER of 13,619 pounds per QALY gained, compared with lamivudine followed by tenofovir. For HBeAg-negative patients, tenofovir followed by lamivudine has an ICER of 9811 pounds per QALY gained, compared with best supportive care. A more clinically appropriate treatment strategy of tenofovir followed by tenofovir plus lamivudine has an ICER of 13,854 pounds per QALY gained, compared with tenofovir followed by lamivudine. The ERG uncovered a number of errors in the submission and these ICERs approximately doubled when the analysis was corrected and reran. The guidance issued by NICE on 22 July 2009 states that tenofovir disoproxil, within its marketing authorization is recommended as an option for the treatment of people with chronic HBe-Ag-positive or HBe-Ag-negative hepatitis B in whom antiviral treatment is indicated.<br/