HBV Rebound Common in Patients Taking Oral Meds

[Guest guest]

http://www.hivandhepatitis.com/hep_b/news/2011/0503_2011_a.html

HBV Rebound Common in Patients Taking Oral Meds

SUMMARY

Nearly half of patients taking nucleoside/nucleotide analogs to treat hepatitis

B experienced viral breakthrough over 5 years, and about 40% of these were not

attributable to drug resistance mutations.

Hepatitis B Virus

Nucleoside/nucleotide analogs including lamivudine (Epivir-HBV), adefovir

(Hepsera), entecavir (Baraclude), telbivudine (Tyzeka), and tenofovir (Viread)

are highly active against hepatitis B virus (HBV), but drug resistance can

emerge over time, compromising the effectiveness of long-term therapy. This is

especially likely if agents are used one at a time and when adherence is poor.

As described in the May 2011 issue of Hepatology, Chanunta Hongthanakorn,

Lok, and colleagues from the University of Michigan conducted a study to

determine the likelihood of virological breakthrough and genotypic resistance

among chronic hepatitis B patients receiving nucleoside/nucleotide analogs in

routine clinical practice.

Below is an edited excerpt from a recent press release issued by Hepatology

publisher Wiley-Blackwell describing the study and its findings.

Hepatitis B Virus Reemerges with Long-Term

Nucleoside Analog Treatment

Virological breakthrough not linked to antiviral drug resistance; non-adherence

to medication likely.

April 27, 2011 -- A recently published study revealed that virological

breakthrough (VBT) is common in patients receiving nucleoside analogs (NUCs) for

chronic hepatitis B. Nearly 40% of the VBTs found were not related to antiviral

drug resistance. Details of this retrospective study are published in the May

issue of Hepatology, a journal published by Wiley-Blackwell on behalf of the

American Association for the Study of Liver Diseases.

VBT is the first manifestation of antiviral drug resistance during NUC therapy

of chronic hepatitis B. NUC drugs approved for treatment of chronic hepatitis B

include lamivudine (LAM), adefovir (ADV), entecavir (ETV), telbivudine (TBV),

and tenofovir (TDF). While the medications suppress the virus with few side

effects, they do not eradicate HBV and require long-term treatment to provide

clinical benefit. With long-term NUC therapy, studies have shown an increasing

risk of drug resistance particularly with monotherapy regimens.

In the current study, Lok, MD, and colleagues from the University of

Michigan Health System examined the incidence of VBT and genotypic resistance

(GR) in 148 patients with chronic hepatitis B who were treated with NUCs between

January 2000 and July 2010. The mean age of study participants was 45 years and

73% were male. Researchers reviewed medical records and recorded patient

demographics, hepatitis B virus (HBV) markers, liver panel, blood counts and

liver histology.

Results showed that during a mean follow-up of 38 months, 39 (26%) patients had

at least 1 VBT, and upon retesting, 15 (38%) of these patients did not have a

VBT and 10 had no evidence of GR. Researchers reported the probability of VBT,

confirmed VBT [on 2 consecutive tests], and GR at five years was 46%, 30%, and

34%, respectively. " Our analysis showed an alarmingly high rate of VBT in

clinical practice and the only factor significantly linked to VBT was failure to

achieve undectectable HBV DNA, " said Dr. Lok.

HBV DNA decreased in the 10 patients who initially experienced a VBT, but who

did not have confirmed VBT or GR, when the same drug regimen was maintained.

Nine of these patients had undetectable HBV DNA at the most recent follow-up, a

mean of 7 months after the initial VBT. These data suggest that non-adherence to

medication may be a common cause of VBT. " Counseling patients with chronic

hepatitis B on the importance of medication adherence, and confirming

reemergence of the virus and genetic mutations that cause resistance, can help

to avoid unnecessary changes to antiviral treatments, " advised Dr. Lok.

Investigator affiliations: Division of Gastroenterology, Department of Internal

Medicine, University of Michigan Health System, Ann Arbor, MI.

5/3/11

Reference

C Hongthanakorn, W Chotiyaputta, K Oberhelman, and others. Virological

breakthrough and resistance in patients with chronic hepatitis B receiving

nucleos(t)ide analogs in clinical practice. Hepatology 53(5) (abstract). May

2011.

Other Source

Wiley-Blackwell. Hepatitis B Virus Reemerges with Long-Term Nucleoside Analog

Treatment. Media advisory. April 27, 2011.