Lamivudine and high-dose interferon alpha 2a combination treatment in naïve HBeAg-positive immunoactive chronic hepatitis B in children: an East Mediterranean center's experience

Lamivudine resistance in children with chronic hepatitis B

Currently, although lamivudine (LAM) has a low genetic barrier, only interferon-alpha and LAM are available as a first-line treatment in children with chronic hepatitis B (CHB). LAM is a potent inhibitor of hepatitis B virus-deoxyribonucleic acid (HBV-DNA) polymerase replication by termination of the proviral HBV-DNA chain. LAM has a good safety and tolerability profile in CHB patients with hepatic decompensation. However, the main disadvantages of this HBV reverse transcriptase inhibitor are: (1) pre-existing covalently closed circular DNA cannot be eradicated by LAM, thus relapse after therapy withdrawal is frequent; and (2) although the longer LAM treatment induced the higher seroconversion rate, the risk of viral resistance increased through the selection of YMDD (tyrosine, methionine, aspartate, aspartate) motif. Insufficient suppression of viral replication leads to the emergence of resistant strains that could result in virological breakthrough which is usually followed by biochemical breakthrough. Mutant strains affects additional resistance and cross resistance, leading to drug resistance in a significant number of CHB patients. In this case, efficacy of more powerful anti-viral agents with higher genetic barrier against development of resistance is diminished. Furthermore, strains that are resistant to LAM could bring about vaccine escape mutants, decreasing the efficacy of HBV vaccine. A more potent drug with a high genetic barrier to resistance needs to be approved as the first-line treatment option for CHB in children.

Treatment of children with HBeAg-positive chronic hepatitis B: a systematic review and meta-analysis

BACKGROUND

Effective management of children with chronic hepatitis B is still an unresolved issue.

AIM

To assess the outcome of different therapeutic regimens among children with HBeAg-positive chronic hepatitis B.

METHODS

Electronic database searches identified clinical trials that completed specific periods of treatment and follow-up. Sustained response rates were defined by the loss of HBV DNA and HBeAg, and by the normalization of liver enzymes. The loss of HBsAg and seroconversion to anti-HBs were also listed.

RESULTS

Our searches found 20 eligible articles (1112 enrolled patients, 2-18 years old). Interferon-alpha therapy showed significantly higher sustained response rate and loss of HBsAg than no therapy (Odd's ratio 3.0, 95% confidence interval 1.6-5.4; and 2.3, 1.1-11.3, respectively). The sustained response rate was not significantly different between interferon and interferon plus lamivudine, or plus prednisone, or plus hepatitis B vaccine; this rate was significantly higher for interferon compared with combined interferon plus levamisole or vitamin E.

CONCLUSION

Interferon-alpha is still the most effective treatment option for children with HBeAg-positive chronic hepatitis B. Randomized trials are warranted for further comparing interferon to newer antiviral agents in terms of efficacy, safety, emergence of mutant variants, and cost/benefit ratio.

Treatment of chronic hepatitis B and C in children

HBV and HCV are the predominant causes of chronic viral hepatitis in children and adults. The main purposes of the present review are to provide the reader with a comprehensive overview of the currently available therapies for chronic hepatitis B and C in children and to critically review the current guidelines and indications for treatment provided by the major international societies and by the consensus of expert panels. Overall, a conservative approach is generally warranted in children with chronic hepatitis B. For HCV, the high effectiveness of pegylated interferon and ribavirin in children with genotype 2 or 3 chronic infection supports the decision to treat. For genotype 1 infection the encouraging results of the use of direct antiviral agents in adults suggest a more conservative approach.

Combination therapy of lamivudine and interferon-alpha in pediatric patients with chronic hepatitis B in Bangladesh: a safe and effective therapeutic approach for pediatric CHB patients in developing countries

Hepatitis B virus (HBV) is mainly transmitted during birth or perinatal period, however, treatment is not usually recommended for pediatric patients with chronic hepatitis B (CHB). Twelve pediatric patients with CHB in Bangladesh were treated with both lamivudine and interferon. Lamivudine was given at a dose of 3 mg/kg, daily for 12 months. Two months after commencement of lamivudine therapy, all patents were given interferon-alpha (3 million IU/square meter of body surface area) three times weekly, subcutaneously for 10 months. Combination therapy was safe for all pediatric CHB patients. The levels of serum HBV DNA became undetectable (less than 500 copies/ml) in 8 patients and reduced in 4 patients after the end of therapy. Anti-HBe was detected in 10 of 12 patients at this time point. The levels of serum alanine aminotransferase (ALT) were significantly reduced in these patients (p less than 0.05) due to therapy. Neither flare of HBV DNA nor elevation of serum ALT were detected during follow-up. In conclusion, combination therapy with lamivudine and interferon-alpha represents a new and novel therapeutic option for treatment of pediatric CHB patients.

Recent data on treatment of chronic hepatitis B with nucleos(t)ide analogues

Forty years ago in 1967, Professor Blumberg discovered the Australian Antigen, later known as the hepatitis B surface antigen, and was awarded the Nobel Prize. This discovery enables the diagnosis of hepatitis B virus (HBV) infection and defines its epidemiology. Viral hepatitis B infection affects global health situation, and chronic hepatitis B (CHB) is particularly serious in the Asia-Pacific region. HBV vaccines created the first breakthrough in HBV prevention. Through universal HBV vaccination program for the newborns, promoted since the mid-1980s, the main route that perpetuates chronic infection from mother to child is curbed. Most children and young adults now have immunity against HBV infection. The next breakthrough comes with therapy for CHB. This prevents progression to cirrhosis and hepatocellular carcinoma. Standard interferon therapy with modest efficacy has been largely replaced by therapy with nuclos(t)ide analogues or pegylated interferons alfa-2a and -2b. Lamivudine was approved by the FDA USA in 1998, followed by adefovir dipivoxil in 2002, entecavir in 2005, and telbivudine in 2006. Clevudine, tenofovir, and many promising candidates are in different stages of development and clinical trial. This paper critically reviews recent data published or presented since the APASL Consensus and Guideline Update of 2005. Clinical efficacy mostly in patients with raised serum alanine aminotransferase will be analyzed.

Systematic review: combination therapies for treatment-naïve chronic hepatitis B

BACKGROUND

There is a renewed interest in use of combination therapies in treatment-naïve chronic hepatitis B (CHB) because of limitations of monotherapies.

AIM

To discuss the current status of combination therapies in treatment-naïve CHB.

METHODS

PubMed search was done using 'combination', 'sequential' and 'chronic hepatitis B' as the search terms.

RESULTS

The two most popular combination therapies include 'combination of nucleos(t)ide analogues' and 'combination of interferons and nucleos(t)ide analogues'. Combination therapies using two nucleos(t)ide analogues do not lead to higher long-term efficacy. However, addition of a nucleos(t)ide analogue with a good resistance profile to a nucleos(t)ide analogue with a lower genetic barrier to resistance decreases the risk of emergent resistance to the latter. Greater sustained virological, biochemical and seroconversion rates are observed with addition of lamivudine to conventional interferon, but pegylated-interferon monotherapy is equally effective as combination with lamivudine. Again, resistance to lamivudine is lower with its combination with interferons.

CONCLUSIONS

The answer to the question whether hepatitis B can be treated better with combination or monotherapy remains largely unknown. Additional trials are warranted of combination therapies of peginterferon and potent nucleos(t)ide analogues or therapies with the combined use of nucleos(t)ide analogues or immunomodulators.

Natural history and clinical management of chronic hepatitis B virus infection in children

Hepatitis B virus (HBV) infection may cause acute, fulminant, or chronic hepatitis, leading to liver cirrhosis or hepatocellular carcinoma. Despite the availability of effective vaccine, HBV infection during infancy or early childhood is common in areas of high endemicity. In these regions, mother-to-infant transmission accounts for approximately 50% of chronic infections. Although the natural history of HBV infection in adults is well characterized, little information is available in the literature regarding the natural history of HBV infection in children. Similar to infection in adults, chronic HBV infection in children can be divided into distinct phases: immune tolerant, immune clearance, and inactive carrier state. However, acute exacerbation, with reactivation of HBV replication and re-elevation of alanine aminotransferase levels after hepatitis B e antigen seroconversion, is relatively rare in children, in comparison to adults. Although several potent antiviral agents are now available for the treatment of chronic hepatitis B, experience with these agents in the pediatric setting is limited. To date, conventional interferon alpha and lamivudine are the only two antiviral agents approved to treat chronic hepatitis B in children. The rapid emergence of resistant HBV associated with long-term lamivudine therapy, as well as poor tolerability associated with conventional interferon alpha, are factors that should be considered before initiating antiviral therapy. This article reviews current knowledge regarding the natural history and treatment of chronic hepatitis B in children. Factors that affect the natural history of HBV infection in children are also reviewed.