Antiviral Drug Resistance Testing in Patients with Chronic Hepatitis B

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http://www.springerlink.com/content/w5k156l7723un544/

Digestive Diseases and Sciences

DOI: 10.1007/s10620-011-1816-6Online First™

Original Article

Antiviral Drug Resistance Testing in Patients with Chronic Hepatitis B

Wai-Sun Wong, Grace Lai-Hung Wong, Chi-Hang Tse, Lilly K. W. Yuen,

Hoi-Yun Chan, A. Locarnini and Henry Lik-Yuen Chan

Abstract

Background

Antiviral drugs against hepatitis B virus are limited by the emergence of drug

resistance.

Aims

We aimed to study the impact of drug resistance testing on treatment decisions.

Methods

In part 1 of this study, consecutive patients with chronic hepatitis B who had

antiviral drug resistance testing were studied. Part 2 was a two-step

questionnaire survey including ten characteristic case scenarios. Hepatologists

were asked about their treatment decisions before and after the knowledge of

drug resistance results.

Results

Fifty-one patients underwent drug resistance testing, most of whom were on

lamivudine, adefovir dipivoxil or entecavir monotherapy. Thirty-four (67%)

patients had drug-resistant mutants detected, 4 (8%) had low viral load, and 13

(25%) harboured wild-type virus. Twenty-nine of 34 (85%) patients harbouring

drug-resistant mutants and 9 of 17 (53%) patients with no mutants detected

changed their drug regimens (P = 0.038). In part 2, 18 hepatologists completed

all two questionnaires. Overall, treatment decision was modified in 52% of cases

upon receiving the drug resistance testing results. The detection of rtA181V/I

resulted in decision changes in most hepatologists, with the preferred treatment

switching from tenofovir to entecavir. When no mutants were detected in partial

responders to entecavir monotherapy, most hepatologists chose to increase the

dose of entecavir.

Conclusions

Drug-resistant mutations are detected in around two-thirds of chronic hepatitis

B patients undergoing drug resistance testing. Drug resistance testing alters

management in over half of the cases, and should be considered in all patients

with virological breakthrough and suboptimal virological suppression.