VIENNA – Treatment of individuals chronically infected with hepatitis B virus (HBV) with the nucleotide analog tenofovir disoproxil fumarate significantly linked with a substantial cut in the incidence of hepatocellular carcinoma (HCC) compared with those who received the nucleoside analog entecavir, according to a review of more than 29,000 Hong Kong patients.
This is the second reported study to find that association. In January 2019, a study of more than 24,000 Korean residents chronically infected with HBV showed a similar, statistically significant link between treatment with tenofovir disoproxil fumarate (Viread) and a lower incidence of HCC compared with patients treated with entecavir (Baraclude) (), , said at the meeting, sponsored by the European Association for the Study of the Liver (EASL).
However, another report published just a few days before Dr. Wong spoke failed to find an association between tenofovir disoproxil treatment of HBV and the subsequent rate of HCC compared with patients treated with entecavir. That study comprised nearly 2,900 HBV patients treated at any of four Korean medical centers (J Hepatol. 2019 Apr.).
Dr. Wong noted that although current guidelines from EASL cite both tenofovir disoproxil and entecavir (as well as tenofovir alafenamide [Vemlidy]) as first-line treatments for chronic HBV infection (), some evidence suggests that tenofovir disoproxil might produce effects subtly different from those of entecavir.
At the meeting in Vienna, for example, a report on 176 Japanese patients with chronic HBV showed that those who were treated with a nucleotide analog such as tenofovir disoproxil produced higher serum levels of interferon-lamda3 compared with patients treated with entecavir, and increased levels of this interferon could improve clearance of HBV surface antigen (). The most recent EASL guidelines for treatment of chronic hepatitis B infection also list tenofovir disoproxil, entecavir, and tenofovir alafenamide as preferred agents ( ).
The data Dr. Wong and her associates analyzed came from health records kept for about 80% of Hong Kong’s population in the Clinical Data Analysis and Recordingof the Hospital Authority of Hong Kong. From January 2010 to June 2018, this database included 28,041 consecutive patients chronically infected with HBV and treated with entecavir, and 1,309 consecutive patients treated with tenofovir disoproxil. These numbers excluded patients treated for less than 6 months, patients coinfected with hepatitis C or D virus, patients with cancer diagnosed or a liver transplanted before or during their first 6 months on treatment, and patients previously treated with an interferon or nucleos(t)ide.
During an average follow-up of 2.8 years of tenofovir disoproxil treatment, 8 patients developed HCC, and during an average follow-up of 3.7 years of entecavir treatment, 1,386 patients developed HCC, reported Dr. Wong, a hepatologist and professor of medicine at the Chinese University of Hong Kong.
In a multivariate analysis that adjusted for demographic and clinical differences, treatment with tenofovir disoproxil linked with a statistically significant 68% reduced rate of HCC development compared with the entecavir-treated patients, she said. In a propensity score–weighted analysis, tenofovir disoproxil linked with a statistically significant 64% reduced rate of incident HCC, and in a propensity score–matched analysis tenofovir disoproxil linked with a 58% reduced rate of HCC, although in this analysis, which excluded many of the entecavir-treated patients and hence had less statistical power, the difference just missed statistical significance.
As an additional step to try to rule out the possible effect of unadjusted confounders, Dr. Wong and associates analyzed the links between tenofovir disoproxil and entecavir treatment and two negative-control outcomes, the incidence of lung cancer and the incidence of acute myocardial infarction. Neither of these outcomes showed a statistically significant link with one of the HBV treatments, suggesting that the link between treatment and HCC incidence did not appear because of an unadjusted confounding bias, Dr. Wong said. The Hong Kong database did not include enough patients treated with tenofovir alafenamide to allow assessment of this drug, she added.
Dr. Wong has been an adviser to Gilead and a speaker for Abbott, AbbVie, Bristol-Myers Squibb, Gilead, Janssen, and Roche. Tenofovir disoproxil fumarate is marketed by Gilead, and entecavir is marketed by Bristol-Myers Squibb.
SOURCE: Wong GL et al. .