Current pharmacotherapy for hepatitis B infection

Multicenter evaluation of the VERSANT hepatitis B virus DNA 3.0 assay

The VERSANT hepatitis B virus (HBV) 3.0 Assay (branched DNA [bDNA]) (referred to herein as VERSANT 3.0) was evaluated at four external sites for analytical sensitivity, specificity, reproducibility, linearity of quantification, and limits of detection. In addition, each of the test evaluation sites provided HBV DNA-positive clinical samples that were previously analyzed by one of three commercially available HBV DNA quantitative tests: Digene Hybrid Capture II HBV DNA Test (Digene); VERSANT HBV DNA 1.0 Assay (bDNA) (VERSANT 1.0); and COBAS AMPLICOR HBV Monitor Test (COBAS AMPLICOR). These samples were reexamined using VERSANT 3.0. The results from these studies showed that VERSANT 3.0 has high specificity (99.3%), excellent reproducibility (between-run coefficient of variation [CV] = 1.6 to 9.4%; within-run CV = 6.5 to 20.7%), and a broad linear range of quantification (2.0 x 10(3) to 1.0 x 10(8) HBV DNA copies/ml) that facilitate the monitoring of HBV DNA levels at diagnosis and throughout the course of treatment. In general, correlation was very good between results obtained from clinical samples analyzed by VERSANT 3.0 and the comparative HBV DNA quantitative assays (VERSANT 1.0, R(2) = 0.900; Digene, R(2) = 0.985; COBAS AMPLICOR, R(2) = 0.771). The greatest differences in comparative quantitation occurred at HBV DNA levels approaching the limits of the dynamic ranges for the comparative assays. The performance characteristics of the new VERSANT 3.0 assay demonstrated that it provides a reliable and robust method for routinely monitoring serum HBV DNA levels in assessing disease activity and determining response to antiviral treatment.

Oxymatrine therapy for chronic hepatitis B: A randomized double-blind and placebo-controlled multi-center trial

AIM: To evaluate the efficacy and safety of capsule oxymatrine in the treatment of chronic hepatitis B.

METHODS: A randomised double-blind and placebo-controlled multicenter trial was conducted. Injection of oxymatrine was used as positive-control drug. A total of 216 patients with chronic hepatitis B entered the study for 24 wk, of them 108 received capsule oxymatrine, 36 received injection of oxymatrine, and 72 received placebo. After and before the treatment, clinical symptoms, liver function, serum hepatitis B virus markers, and adverse drug reaction were observed.

RESULTS: Among the 216 patients, six were dropped off, and 11 inconsistent with the standard were excluded. Therefore, the efficacy and safety of oxymatrine in patients were analysed. In the capsule treated patients, 76.47% became normal in ALT level, 38.61% and 31.91% became negative both in HBV DNA and in HBeAg. In the injection treated patients, 83.33% became normal in ALT level, 43.33% and 39.29% became negative both in HBV DNA and in HBeAg. In the placebo treated patients, 40.00% became normal in ALT level, 7.46% and 6.45% became negative both in HBV DNA and in HBeAg. The rates of complete response and partial response were 24.51% and 57.84% in the capsule treated patients, and 33.33% and 50.00% in the injection treated patients, and 2.99% and 41.79% in the placebo treated patients, respectively. There was no significance between the two groups of patients, but both were significantly higher than the placebo. The adverse drug reaction rates of the capsule, injection and placebo were 7.77%, 6.67% and 8.82%, respectively. There was no statistically significant difference among them.

CONCLUSION: Oxymatrine is an effective and safe agent for the treatment of chronic hepatitis B.

Agents in clinical development for the treatment of chronic hepatitis B

Chronic hepatitis B remains a public health problem of global importance despite the availability of an effective vaccine. Between 350 and 400 million people, approximately 6% of the world's population, suffer from chronic hepatitis B and face a 30% likelihood of developing cirrhotic liver disease or hepatocellular carcinoma. Current treatment options include three monotherapies of subcutaneous interferon, oral nucleoside lamivudine and oral nucleotide adefovir dipivoxil. Unfortunately, these agents have not effectively and frequently been able to attain a 'cure' or complete eradication of the virus. Consequently, the expectation of current therapies is confined to the achievement of clinically beneficial and durable responses defined by lasting suppression of virus replication, histological improvement and increased survival for patients with decompensated liver diseases. Other disadvantages include the undesirable tolerability of interferon, the rapid resistance to lamivudine and the compromise between efficacy and toxicity that led to the development of the 10 mg dose of adefovir dipivoxil. Clearly, better therapeutics and treatment strategies are needed. Increased potency, activity against current treatment-refractory viruses, as well as efficacy in difficult-to-treat populations will be critical to meeting the therapeutic challenge of chronic hepatitis B.

Drug treatment of pediatric chronic hepatitis B

Children with chronic hepatitis B are at risk of developing long-term complications such as cirrhosis and hepatocarcinoma. It is estimated that half to two-thirds of affected children will clear the hepatitis B e antigen (HBeAg) naturally before reaching adulthood. As in adults, treatments in children accelerate the virological response (DNA negativity and HBeAg loss, with anti-HBe seroconversion), which is associated with normalization of transaminase levels. Treatments also favor subsequent loss of hepatitis B surface antigen (HbsAg), the ultimate goal for minimizing long-term consequences. Interferon-alpha was the first approved treatment for pediatric chronic hepatitis B, and was shown to promote DNA negativity and HBeAg loss in 26% of treated patients (6 MU/m(2) body surface area for 6 months) at 1 year and 33% at 18 months (versus 11% in controls). 10% of treated patients also lost HBsAg. Adverse effects mainly included fever, flu-like symptoms and growth impairment during the treatment phase. Nucleotide analogs have now emerged as promising alternatives for the treatment of chronic hepatitis B. Lamivudine dose-ranging studies showed a higher clearance in children, and the optimal dosage was established to be 3 mg/kg once daily in children up to 12 years of age. Efficacy trials showed complete virological response (HBeAg loss and DNA negativity) in 23% of all treated patients after 1 year, and in 34% of patients with initial transaminase levels >2 x the upper limit of normal. Lamivudine resistance due to mutant/variant viruses is observed in 19% of children after 1 year, a figure that may increase by an average of 20% per year. Other nucleotide analogs, such as adefovir, will soon be tested in children, and have shown promising results in adults without so far demonstrating viral resistance. Finally, therapeutic vaccines aiming to induce a cellular immune response towards hepatitis B antigens are being tested in adults, but no clinical benefit has so far been established.

Combination therapy for children with chronic hepatitis B virus infection

BACKGROUND AND AIM

To compare the therapeutic efficacy of two different interferon (INF)-alpha and lamivudine (LAM) combination therapy regimens in childhood chronic hepatitis B (CHB) infections.

METHODS

Thirty-two children with CHB infection were prospectively evaluated in two random groups. In the first group, patients received INF-alpha 10 MU/m2 and LAM 4 mg/kg (max 100 mg) simultaneously for 6 months, and then LAM alone was continued for 6 months. In the second group, LAM was started alone for the first 2 months, then INF-alpha added to LAM for 6 months, after which INF-alpha was stopped, and LAM alone was continued for 4 months. The same doses of LAM and INF-alpha were used in both groups.

RESULTS

In the first group, the mean values of alanine aminotransferase (ALT) were 125 +/- 100 IU/L and 28 +/- 8 IU/L at the beginning of the treatment and at the end of the 12 months, respectively (P < 0.05). At the end of 6 months of the follow-up period, the mean ALT value was 36 +/- 37 IU/L. In group 2, mean ALT values were 111 +/- 63 IU/L, 35 +/- 2 IU/L and 34 +/- 2 IU/L initially, at the end of 12 months and at the end of 6 months of follow up, respectively (P < 0.05). At the end of therapy, the ratios of hepatitis B early antigen (HBeAg) clearance and antibody to HBeAg (anti-HBe) seroconversion were 65% and 47% in group 1 and 60% and 40% in group 2, respectively (P > 0.05). After 6 months from completion of therapy, rates of seroconversion to anti-HBe were found to be 64% and 47% in group 1, and 53% and 46% in group 2, respectively (P > 0.05). Hepatitis B virus (HBV) DNA was detectable by polymerase chain reaction in only one patient in group 1 at the end of therapy and 6 months after termination of therapy. Clearance of HBV DNA in group 2 was observed in all but one patient at the end of the therapy. However, two patients relapsed within 6 months of cessation of therapy. Complete response occurred in 47% and 40% of patients at the end of the therapy in group 1 and 2, respectively (P > 0.05). These ratios were changed to 47% and 46%, respectively, 6 months after discontinuation of drugs (P > 0.05).

CONCLUSIONS

Comparison of our two different combination regimens disclosed similar results in the normalization of ALT, clearance of HBeAg and HBV DNA and seroconversion to anti-HBe. However, the most beneficial combination of LAM and INF-alpha treatment modalities needs to be further investigated.

Chronic hepatitis B: current and future treatment options

Hepatitis B, a major viral infection that can lead to cirrhosis and hepatocellular carcinoma, is the ninth most common cause of death worldwide. Prevention of hepatitis B virus transmission is key to reducing the spread of this serious condition. Management of chronic hepatitis B requires significant knowledge of approved pharmacotherapeutic agents and their limitations. Today, agents approved by the Food and Drug Administration for this infection are interferon-alpha-2b and lamivudine. Newer agents are being developed and hold promise: adefovir, famciclovir, ganciclovir, lobucavir, entecavir, emtricitabine, L-deoxythymidine, clevudine, a therapeutic vaccine, and thymosin alpha-1. Therapeutic options for managing hepatitis infection after liver transplantation are also evolving. These include hepatitis B immunoglobulin and nucleoside analogues.

Lamivudine for the treatment of chronic hepatitis B

Lamivudine (Zeffix, Epivir, GlaxoSmithKline) is the most important recent advance in the treatment of chronic hepatitis B in both adults and children. It is the only available oral treatment and has an excellent safety profile, which makes it even more attractive. It increases the rate of hepatitis B e antigen (HBeAg) loss and seroconversion in compensated chronic HBeAg-positive carriers, with subsequent improvement of histology at a similar rate as IFN-alpha. Lamivudine is mostly active in patients with elevated transaminases and is not effective in compensated patients with quiescent disease. Long-term follow-up studies are still required to evaluate long-term benefits, including those on hepatitis B surface antigen (HBsAg) seroconversion rate and disease evolution control. In decompensated patients, the drug can stabilise and improve liver function, allowing the patient to wait safely for transplantation. Patients may improve to such an extent that transplantation can be postponed. Combined with hepatitis B immunoglobulin (HBIG), lamivudine considerably decreases the risk of graft re-infection after transplantation. It is also active in chronic HBeAg-negative hepatitis patients, for whom IFN is less efficient. The major drawback is the emergence of the tyrosine-methionine-aspartate-aspartate (YMDD) mutation, which prevents further efficacy of the drug and may lead to flares of hepatitis. Due to the questions the YMDD mutation raises and because hepatitis B is a complex disease, indications for treatment must be established with care and only by physicians with expert knowledge of the disease, the drug and YMDD mutation-related issues.