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Hepatitis B treatment: Current best practices, avoiding resistance

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ABSTRACT

All patients who are positive for hepatitis B virus (HBV) DNA should be considered for antiviral treatment. Potency in suppressing HBV DNA is the main factor in the choice of first-line therapy; entecavir and tenofovir constitute the most potent nucleoside and nucleotide analogues to date with the lowest rates of resistance. Viral negativity may reduce the development of liver failure and the need for transplant, although these benefits need to be demonstrated prospectively. Loss of hepatitis B surface antigen, or seroconversion, may represent a new treatment paradigm. The development of resistance to therapy can result in virologic breakthrough and serious clinical consequences. Use of the most potent agents as first-line therapy lowers the risk of resistance; but if resistance develops, adding an additional agent, rather than switching to another therapy, is advised.

KEY POINTS

  • Consider treatment for chronic HBV infection for all patients who are positive for HBV DNA, as viral load levels as low as 300 copies/mL confer a risk for hepatocellular carcinoma.
  • The goal of therapy is an undetectable level of HBV DNA; initiate therapy with the most potent agent to limit the possibility of resistance.
  • Preventing resistance to therapy is crucial for successful treatment of chronic HBV infection.


 

References

Guidelines for the management of hepatitis B virus (HBV) infection can be daunting to clinicians. Further, although established practice guidelines can provide direction, treatment of chronic HBV infection is characterized by uncertainties that can hinder optimal patient care. Reservations about when to initiate and terminate therapy, cost issues, and the development of resistance to therapy are among the factors that impede adequate treatment. This article offers a straightforward roadmap for the management of chronic HBV infection, based on interpretation of recently released guidelines,1–3 and strategies for preventing and managing resistance to antiviral therapy.

DECIDING TO TREAT

Key factors: Viral load and ALT

Two important factors influencing the decision to treat are viral load (HBV DNA) and alanine aminotransferase (ALT) level; although these are relatively straightforward measures, other factors can cause clinicians to avoid or delay treatment.

A simple guideline is to discuss treatment with any patient who is positive for HBV DNA. The most recent guidelines for the treatment of HBV infection, published by the European Association for the Study of the Liver (EASL), recommend an HBV DNA level of 2,000 copies/mL as a threshold for initiating therapy; this recommendation applies to patients who are either positive or negative for hepatitis B e antigen (HBeAg).3

The Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer-Hepatitis B Virus (REVEAL-HBV) study investigators used ultrasensitive polymerase chain reaction (PCR) to quantify HBV DNA levels and conducted a time-dependent multiple Cox regression analysis of HBV DNA level and the risk of hepatocellular carcinoma (HCC).4,5 The length of time at a given DNA level was weighted in determining the adjusted hazard ratio. With an HBV DNA level less than 300 copies/mL defined as the reference group, risk of HCC increased commensurate with increasing HBV DNA level; even at levels ranging from 300 to 10,000 copies/mL, longer duration of HBV DNA positivity increased risk. This group also found HBV DNA level to be an independent risk factor for cirrhosis.

Patients who are HBV DNA negative are at much lower risk of cirrhosis and HCC than HBV DNA–positive patients; HBV DNA–negative patients being treated with antiviral drugs are much less likely to develop resistance to treatment, provided that first-line medications such as tenofovir or entecavir are used.

The definition of a “healthy” ALT level is controversial. In my opinion, an abnormal ALT is greater than 19 IU/mL for women and greater than 25 IU/mL for men; in either setting, treatment should be instituted if the patient is HBV DNA positive. This position is supported by a recently published algorithm,6 a recent National Institutes of Health conference on management of HBV,7 and other sources.8–12

Barriers to optimal treatment

Patient reluctance to undergo invasive tests, concerns about resistance, confusion about when to initiate therapy, cost, and other issues can impede timely and effective treatment of HBV infection.

Invasive studies. Liver histology is a key driver for initiating treatment, but many patients resist undergoing a liver biopsy. Ultrasonography has enabled noninvasive determination of spleen size, portal vein size, and liver tissue and surface heterogeneity; noninvasive assessments such as measurement of aspartate aminotransferase, varices, serum markers of fibrosis, and platelet count may provide clues to advanced liver fibrosis. Eventually, ultrasonographic elastography to measure liver stiffness and magnetic resonance scans may be common in clinical practice for noninvasive evaluation of liver damage. Ultimately, however, liver biopsy remains a valuable tool to motivate patients with chronic HBV infection to initiate and continue antiviral therapy.

Rationales for avoiding or delaying treatment. Concern about the development of resistance to treatment, as with antiviral therapy directed against human immunodeficiency virus (HIV), is one reason not to treat. The absence of clear guidelines regarding the appropriate time to terminate therapy has also led to avoidance or delay of treatment. The lack of risk calculators similar to the Framingham risk score, which estimates the risk of coronary heart disease, has limited the treatment of chronic HBV infection.

Cost. Cost must be examined in relation to the cost of resistance developing and the cost of treating complications. Lamivudine, considered a third-line treatment for chronic HBV infection, is an inexpensive drug. However, up to 70% of patients will develop resistance to lamivudine over 5 years3,6; most will require combination therapy, with its attendant costs, and may eventually require transplants or experience poor clinical outcomes. Although the initial costs of potent first-line therapies (tenofovir, entecavir, and pegylated interferon) are high, cost modeling shows that they are less expensive over the long term when the overall cost of care is considered.13,14

GOALS OF THERAPY: VIRAL LOAD SUPPRESSION, SEROCONVERSION

Profound suppression of viral load reduces the risk of resistance and is the ultimate goal of therapy for HBV infection. We can infer from recent data15 that achieving HBV DNA negativity has led to improved outcomes in patients with chronic HBV infection; ie, with the increased use of antiviral drugs in the United States over the past 2 decades, the number of liver transplants for end-stage liver disease has fallen dramatically,15 suggesting that profound suppression of viral loads has translated into fewer cases of liver failure and less need for transplants.

Over the same period, the number of patients diagnosed annually with HCC has increased by 146%.15 One interpretation of these data is that patients with chronic HBV infection are living longer, allowing time for HCC to develop. In addition, aggressive surveillance guidelines may account for the increased number of HCC cases since 1990. If detected early, HCC is curable by liver transplant at a rate exceeding 80%.16–18

In discussing treatment duration with patients, I present the ultimate goal of therapy as loss of HB surface antigen (HBsAg), or seroconversion to anti-HBs. At our clinic, we monitor HBsAg at least annually when patients are on long-term therapy.

The cost-effectiveness of treating all patients until they are HBsAg negative needs to be assessed. Incremental cost-effectiveness ratios per quality-adjusted life-year are key to identifying the best course of action.

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