Treatment of HBeAg negative chronic hepatitis B with new drugs (adefovir and others)

Analysis of Clinical Trials of New Drugs for Liver Diseases in China

Background

Liver diseases are a major public health concern worldwide, and the development of novel therapeutic drugs is an important research focus. But no overview has been conducted so far on the current research and development for liver-specific drugs in China, and the actual situation regarding the development and evaluation of new drugs in clinical trials.

Methods

The information of all clinical trials on liver diseases were obtained through the "Pharmaceutical Clinical Trial Registration and Information Disclosure Platform" before December 31, 2020.

Results

A total of 751 clinical trials on liver disease-related drugs were published on the above platform, including 574 chemical drugs, 128 biological products, and 49 traditional Chinese medicine (TCM)/natural drugs. The number of annual registrations has increased on an annual basis. The main indications for these clinical trials are viral hepatitis, liver malignancies, liver abscess, liver transplantation, congenital liver metabolic disease, and other hepatitis-related diseases. Hepatitis B, hepatitis C and liver cancer accounted for 72.4% of the total clinical trials, and the majority are related to generic drug research. There are 103 innovative drugs currently in clinical testing, mainly for hepatitis B, hepatitis C and hepatocellular carcinoma.

Conclusion

The stronger macro-control is required for the clinical trials conducted in China, and it is necessary to identify new therapeutic targets and develop novel drugs for the key liver diseases, as well as preventive hepatitis C vaccines, and targeted therapy, TCM/natural drugs and immunotherapy for liver cancer.

Peginterferon–α2a (40 kDa) (Pegasys®) for hepatitis B

Chronic hepatitis B virus is a serious and life threatening disease afflicting 350 million people worldwide, despite the availability of effective vaccines. Thus far, current monotherapy with conventional interferon-alpha, lamivudine and adefovir dipivoxil remains unsatisfactory. In addition, the use of conventional interferon-alpha needs to be administered subcutaneously three-times weekly and is associated with frequent adverse events. Although nucleoside/nucleotide analogs such as lamivudine and adefovir dipivoxil are well tolerated and can normalize serum alanine aminotransaminase rapidly, 1-year therapy with either lamivudine or adefovir dipivoxil results in low hepatitis B e antigen seroconversion rates. In hepatitis B e antigen-negative patients, most would relapse after lamivudine has been discontinued. Peginterferon-alpha2a, an immunomodulatory agent, is a new drug that has just completed Phase III clinical trials for the treatment of both hepatitis B e antigen-positive and -negative chronic hepatitis B virus infection. The advantage of peginterferon-alpha2a in achieving sustained virologic response over nucleoside/nucleotide analogs is particularly obvious in the hepatitis B e antigen-negative group. In both studies, sustained off-treatment response is superior to the use of monotherapy with lamivudine, and concomitant use of lamivudine and pegnterferon-alpha2a does not have advantages over the use of peginterferon-alpha2a alone. These recent data put peginterferon-alpha2a as the antihepatitis B virus therapy of choice, especially in young and motivated patients with chronic hepatitis B virus infection. However, despite the superiority of peginterferon-alpha2a over currently licensed nucleoside/nucleotide analogs, more research needs to be conducted in order to find the most optimal treatment regimen in our fight against chronic hepatitis B virus infection.

Meta-analyses on viral hepatitis

This article summarizes the meta-analyses of interventions for viral hepatitis A, B, and C. Some of the interventions assessed are described in small trials with unclear bias control. Other interventions are supported by large, high-quality trials. Although attempts have been made to adjust for unclear bias control, analysis of publication bias and other biases is difficult when only few trials are available. It is possible that some of the meta-analyses presented in this article are biased. Furthermore, performing updated cumulative meta-analyses also may introduce random error.3,4 The extent and direction of bias may vary. On average, however, bias leads to overestimated intervention benefits.1 Accordingly, the benefit of some of the interventions suggested in this article may be exaggerated by systematic and random errors. Additional research including large, randomized trials is necessary to clarify the true intervention effects.

Clinical trial: a phase II, randomized study evaluating the safety, pharmacokinetics and anti-viral activity of clevudine for 12 weeks in patients with chronic hepatitis B

BACKGROUND

Clevudine is a polymerase inhibitor that has the unusual feature of delayed viral rebound after therapy in some patients which may be related to its pharmacokinetics.

AIM

To characterize pharmacokinetic and pharmacodynamic profile of clevudine, a potent hepatitis B polymerase inhibitor.

METHODS

A multicenter, randomized study comparing 10, 30 and 50 mg clevudine once daily for 12 weeks with 24 weeks off-treatment follow-up. Patients had chronic HBV infection, were nucleoside-naïve without co-infection. HBV viral load (VL) was assayed using Digene Hybrid Capture II with a lower limit of detection of 4700 copies/mL (940 IU/mL). Clevudine levels were measured using a liquid chromatography/mass spectrometery method.

RESULTS

A total of 31 patients were enrolled into the 10 mg (n = 10), 30 mg (n = 11) and 50 mg (n = 10) groups, respectively. At week 12, the median VL change was -3.2, -3.7 and -4.2 log(10) copies/mL (-0.64, -0.74 and -0.84 log(10) IU/mL) in the 10, 30 and 50 mg groups, respectively (P = 0.012). At week 12, one of 10, five of 11 and two of 10 patients had VL below the assay lower limit of detection. Clevudine was well tolerated with no severe/serious adverse events. The mean plasma half-life of clevudine was 70 h and consequently is not the cause of the delayed viral rebound seen in some patients. Through modelling, 97% of the maximal treatment effect was reached with a 30 mg daily dose. Six patients had genomic changes without viral rebound.

CONCLUSION

Clevudine appears to be a potent and tolerable (over 12 weeks) anti-viral and the optimal dosage appears to be 30 mg once daily.

Indications of liver transplantation in patients with complications of cirrhosis

Transplantation is the only option for reversing liver insufficiency and its complications in patients with end-stage cirrhosis. Transplantation is generally considered after the first episode of decompensation of cirrhosis, provided no specific intervention can result in a longstanding return to the compensated state. Alcohol abuse and hepatitis C virus infection are the predominant causes leading to transplantation in Western countries. In cases of alcoholic cirrhosis, a 6-month period of abstinence is needed before transplantation. Patients with hepatitis C virus infection are considered independent of viral replication, even if post-transplantation recurrence is almost constant. Conversely, in cases of hepatitis B infection, only patients without viral replication (or with extremely low viral load) are suitable candidates. Hepatocellular carcinoma represents an increasing proportion of the indications and offers excellent long-term survival. However, transplantation should be limited to patients with small tumours. HIV infection no longer represents a definitive contraindication.

Interferon-α plus lamivudine vs lamivudine reduces breakthroughs, but does not affect sustained response in HBeAg negative chronic hepatitis B

AIM: To investigate the efficacy of combination treatment of IFN-α and lamivudine compared to lamivudine monotherapy, after 24 mo of administration in HBeAg-negative hepatitis B patients.

METHODS: Fifty consecutive patients were randomly assigned to receive IFN-α-2b (5 MU thrice per week, n = 24) plus lamivudine (100 mg daily) or lamivudine only (n = 26) for 24 mo. Patients were followed up for further 6 mo. The primary outcome was the proportion with sustained virological response (undetectable serum HBV DNA concentrations) and or sustained biochemical response (transaminase levels within normal range) at 30 mo (6 mo after the end of therapy). Secondary end-points were timed from initial virological (biochemical) response to VBR (BBR, respectively) and the emergence of YMDD mutants across the two arms.

RESULTS: Five of twenty-four (21%) patients in the combination arm vs 3/26 (12%) in the lamivudine arm had sustained response (i.e., normal serum transaminase levels and undetectable HBV DNA by PCR assay) 6 mo after treatment discontinuation. A reduction in the emergence of YMDD mutants and in the development of virological breakthroughs was observed in patients receiving combination treatment (10% vs 46%, P = 0.01 and 14% vs 46%, P = 0.03, respectively). Time from initial virologic response to virologic breakthrough (VBR) was greater among initial responders receiving combination treatment compared to those receiving lamivudine (22.9 mo vs 15.9 mo, respectively; P = 0.005).

CONCLUSION: Our results demonstrate that IFN-α plus lamivudine combination therapy does not increase the sustained response, compared to lamivudine. However, combination therapy reduces the likelihood of VBR due to YMDD mutants and prolongs the time period until the breakthrough development.

Review article: current management of chronic hepatitis B

Chronic hepatitis B can be diagnosed in patients with increased aminotransferases, hepatitis B virus viraemia and necroinflammation with fibrosis on liver biopsy. Although, ideally, all patients with chronic hepatitis B should be treated, therapeutic intervention is currently recommended for cases with a relatively satisfactory likelihood of response and/or advanced disease. A realistic therapeutic approach aims to sustain hepatitis B e antigen (HBeAg) loss and hepatitis B e antibody (anti-HBe) seroconversion in HBeAg-positive chronic hepatitis B and to sustain biochemical and virological remission in HBeAg-negative chronic hepatitis B. Currently, three drugs are licensed for chronic hepatitis B: interferon-alpha, lamivudine and adefovir dipivoxil. In patients with HBeAg-positive chronic hepatitis B, all of these drugs achieve HBeAg loss (24-33%) and anti-HBe seroconversion (12-30%) rates significantly superior to those observed in untreated placebo controls. In patients with HBeAg-negative chronic hepatitis B, the sustained off-therapy response rate is 20-25% after a > or =12-month course of interferon-alpha and minimal (<10%), if any, after a 12-month course of lamivudine or adefovir. Long-term lamivudine induces an initial response in 70-90% of patients, but only 30-40% of patients remain in remission after the third year due to progressively increasing viral resistance. Long-term adefovir achieves a response in approximately 70% of patients at 12 months, which is maintained at 24 months with rare (<2%) drug resistance. Adefovir is also effective against lamivudine-resistant strains. Many other anti-viral agents, immunomodulatory approaches and combination therapies are currently being evaluated in chronic hepatitis B.