By Michael Smith, North American Correspondent, MedPage Today
Published: April 27, 2013
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco
AMSTERDAM -- A drug combination widely used in HIV treatment can suppress hepatitis B (HBV) in patients whose immune systems tolerate the virus, a researcher said here.
After 4 years, 76% of patients taking tenofovir and emtricitabine had suppressed the virus, with no resistance and a good safety profile, according to Edward Gane, MD, of Auckland City Hospital in Auckland, New Zealand.
That was significantly more (P=0.016) than the 55% who suppressed the virus while taking tenofovir alone, Gane reported at the meeting of the European Association for the Study of the Liver (EASL).
But "disappointingly" few patients managed to restore their immune response to the virus and those who stopped the therapy after the trial saw their viral loads rebound to earlier levels, Gane said.
Patients in the so-called "immune-tolerant" stage of HBV have high viral loads and no significant immune response; current guidelines do not recommend treatment, although previous studies have shown that tenofovir can suppress the virus.
Gane said it's still not clear whether those guidelines should be altered despite his findings, and urged that long-term prospective studies be conducted to see if the suppression of viral load reduces complications such as cirrhosis and liver cancer.
The researchers enrolled 126 HBV patients with HBV viral loads of at least 1.7 x 107 IU per mL of blood and normal levels of alanine aminotransferase.
They were randomly assigned to daily tenofovir and a placebo or tenofovir and emtricitabine.
The primary endpoint was the proportion of patients who reached a viral load of less than 69 IU per mL, and secondary endpoints included loss of the HBV e antigen (HBeAg) and the development of antibodies to the antigen (HBeAg seroconversion).
A substantial number of people reached the primary endpoint -- 35 of 64 in the tenofovir arm and 47 of 62 in the combination arm -- and even among those with continuing viremia, there were no resistance mutations, Gane reported.
But only five participants had HBeAg loss and only three seroconverted. Also, no patients had a loss of the viral surface antigen (HBsAg) -- a sign of infection -- and none developed antibodies to the antigen.
About half of the patients stopped therapy after the study and all saw their viral loads rebound to pre-study levels within 24 weeks, Gane said.
The study is "very important," commented Fabien Zoulim, MD, PhD, of Hôtel Dieu Hospital in Lyons, France, who was not involved in the research. Zoulim moderated an EASL press conference.
"But it's a first step," he told MedPage Today. "We have shown we can suppress the virus. Next step: Can we prevent some disease outcomes?"
He noted that guidelines leave open the option of treating selected immune-tolerated patients such as those with a family history of cirrhosis or liver cancer. "Now we have more data, so we'll be more confident when we have this type of patients," he said.
The study was supported by Gilead. Gane reported financial links with Gilead, Janssen-Zilag, Novartis, AbbVie, Roche, and Vertex.
Zoulim reported financial links with BMS, Gilead, and Roche.
Primary source: European Association for the Study of the Liver
Source reference:
Chan HL, et al. "Tenofovir DF (TDF) compared to emtricitabine (FTC)/TDF in HBEAG-positive, chronic hepatitis B (CHB) virus-infected patients in the immune tolerant (IT) phase" EASL 2013; Abstract 101.
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