Lamivudine and IFN-beta sequential therapy in HBe antigen-positive patients with chronic hepatitis B virus genotype C infection

Combination of Entecavir or Tenofovir with Pegylated Interferon-α for Long-Term Reduction in Hepatitis B Surface Antigen Levels: Simultaneous, Sequential, or Add-on Combination Therapy

Seroclearance of hepatitis B surface antigen (HBsAg) (“functional cure”) is the optimal endpoint of antiviral therapy for chronic hepatitis B virus (HBV) infection. Currently available anti-HBV therapy includes nucleoside/nucleotide analogs (NAs) and peginterferon-α (Peg-IFNα). Combination of NAs and Peg-IFNα, each with different mechanisms of action, is an attractive approach for treating chronic HBV infection. In earlier studies, compared with monotherapy using IFNα, combination therapy showed greater on-treatment HBV DNA suppression but no difference in the sustained response. However, responses to the combination of non-pegylated IFNα with lamivudine or adefovir were not assessed based on HBsAg quantification but were defined by normal alanine aminotransferase levels, testing negative for hepatitis B e-antigen, and low HBV DNA load over a short term. Here, we reviewed previous reports regarding the effects of combination therapy of entecavir or tenofovir with Peg-IFNα, focusing on long-term reduction in HBsAg levels. Regimens of combination therapy were classified into “simultaneous” combination (“de novo” strategy); “sequential” combination, which involved starting with one therapy followed by the other (“switch-to” strategy); “add-on” combination, which involved adding Peg-IFNα to an ongoing NAs. Some studies have shown promising results, but there is no robust evidence that combination therapy is superior to monotherapy. Large studies are needed to assess the safety and efficacy of combination therapies to increase the rates of HBsAg seroclearance over the long term.

Sequential therapy involving an early switch from entecavir to pegylated interferon-α in Japanese patients with chronic hepatitis B

AIM

The optimal combination of two currently available agents with different mechanisms of action, a nucleos(t)ide analog and pegylated interferon-α (PegIFNα), must be determined to improve treatment of chronic hepatitis B (CHB).

METHODS

In this study, 24 patients with CHB (14 hepatitis B envelope antigen [HBeAg]-positive patients and 10 HBeAg-negative patients) received entecavir for 36-52 weeks, followed by entecavir plus Peg-IFNα2a for 4 weeks, and finally by PegIFNα-2a alone for 44 weeks.

RESULTS

A sustained biochemical, virologic, and serologic response was obtained in 7/24 (29%) patients at 48 weeks post-treatment (2/14 [14%] in HBeAg-positive vs 5/10 [50%] in HBeAg-negative patients, P = 0.085). At baseline, patients with a sustained response had a significantly lower γ-glutamyl transferase level (P = 0.0023), a lower aspartate aminotransferase-to-platelet ratio index (P = 0.049), and a lower α-fetoprotein level (P = 0.042) than those without a sustained response. The decline in hepatitis B surface antigen (HBsAg) levels during the first 24 weeks of PegIFNα-2a treatment in patients with a sustained response was greater than that in patients without (P = 0.017). Additionally, HBsAg seroclearance was achieved in two patients (8.3%): one HBeAg-positive and one HBeAg-negative patient.

CONCLUSION

The outcomes of sequential therapy involving an early switch from entecavir to PegIFNα-2a were unsatisfactory in Japanese patients with CHB. In addition to viral factors, host metabolic characteristics and liver fibrosis/tumor markers can be used for prediction of a sustained response to therapy, but accurate prediction of the therapeutic response is difficult.

Antiviral therapy for chronic hepatitis B: Combination of nucleoside analogs and interferon

The ideal goal of chronic hepatitis B (CHB) treatment should be suppression of emergence of hepatocellular carcinoma through the disappearance of hepatitis B s antigen (HBsAg) rather than the control of serum hepatitis B virus-DNA level. For this purpose, various types of combination therapies using nucleoside analogs (NAs) and interferon (IFN) have been conducted. The therapeutic effects of combination of two different kinds of agents are better than those of the monotherapy using NAs or IFN alone, probably because different pharmaceutical properties might act in a coordinated manner. Recently, combination therapies with NAs and IFN and sequential therapies with NAs administration followed by IFN therapy have been routinely employed. We previously reported that combination therapy using entecavir (ETV) and pegylated (PEG)-IFN showed antiviral effects in 71% of CHB patients; the effect of this combination was better than that using lamivudine (LAM) and PEG-IFN. This is partially explained by the better antiviral effects of ETV than those of LAM. In our analysis, the cohort of CHB consisted of the patients who showed a flare-up of hepatitis before antiviral therapy, and their baseline HBsAg levels were relatively low. Therefore, in addition to the combination of the agents, the appropriate selection of patients is critical to achieve a good viral response.

Long-Term Outcome of Sequential Therapy with Lamivudine Followed by Interferon-β in Nucleoside-Naive, Hepatitis B e-Antigen-Positive Patients with Chronic Hepatitis B Virus Genotype C Infection

It is unclear whether the combination of a nucleos(t)ide analog and interferon (IFN) is superior to monotherapy for treating chronic hepatitis B. In this study, we report the long-term outcomes of sequential therapy using lamivudine followed by IFN-β. This study included 24 hepatitis B e-antigen (HBeAg)-positive patients with chronic hepatitis B virus (HBV) genotype C infection who were treated with lamivudine alone for 16-32 weeks, then with both IFN-β and lamivudine for 4 weeks, and finally with IFN-β alone for 20 weeks. All patients were followed up for 7.1±2.8 years post-treatment. The rate of response, defined as transaminase normalization, HBeAg loss, and HBV DNA <10(4) copies/mL, was 5/24 (21%) at 24 weeks post-treatment. The patients with short-term responses were younger than those with no response (P=0.039). More short-term responders had undetectable HBV DNA at the start of IFN-β compared with the nonresponders (P=0.0059). Subsequently, 4 of the 5 short-term responders remained free of the need for further drug treatment for 4.2±3.5 years post-treatment; more short-term responders remained drug free than did nonresponders (P=0.035). In conclusion, the rate of response to sequential therapy was limited in HBeAg-positive patients with chronic HBV genotype C infection at 24 weeks post-treatment. In the majority of the short-term responders, however, the response was sustainable in the long term.

Combination therapy with a nucleos(t)ide analogue and interferon for chronic hepatitis B: simultaneous or sequential

Currently available antiviral treatment for chronic hepatitis B virus infection can be divided into two classes of therapeutic agents: nucleos(t)ide analogues (NAs) and interferon (IFN). The major advantages of NAs are good tolerance and potent antiviral activity associated with high rates of on-treatment response to therapy; the advantages of IFN include a finite course of treatment, absence of drug resistance, and an opportunity to obtain a post-treatment durable response to therapy. The use of these two antiviral agents with different mechanisms of action in combination is theoretically an attractive approach for treatment. Here, we have reviewed previous reports of either simultaneous or sequential combination therapy with NA and IFN for chronic hepatitis B patients. In previous studies comparing the lamivudine/IFN combination and lamivudine monotherapy in a finite course, combination therapy was associated with higher rates of sustained post-treatment response and lower rates of drug resistance than lamivudine monotherapy. However, NAs such as lamivudine are generally administered indefinitely because of high rates of post-treatment relapse. In addition, concern for drug resistance has decreased significantly with newer, high-potency NAs even when administered alone. In previous studies comparing the lamivudine/IFN combination and IFN monotherapy, the combination therapy showed greater on-treatment viral suppression, but no difference was observed in the post-treatment sustained response. Thus, whether combination therapy confers an additional benefit compared to monotherapy for treating chronic hepatitis B remains unclear. The efficacy of IFN in combination with a more potent NA, such as entecavir or tenofovir, remains to be comprehensively evaluated.

Entecavir and interferon-α sequential therapy in Japanese patients with hepatitis B e antigen-positive chronic hepatitis B

BACKGROUND

The outcomes of sequential therapy with lamivudine followed by interferon have been unsatisfactory in Japanese patients with hepatitis B envelope antigen (HBeAg)-positive chronic hepatitis B. However, the efficacy of sequential therapy with entecavir and interferon remains unclear.

METHODS

Twenty-four HBeAg-positive patients (23 men and 1 woman; mean age 39 ± 7 years) received entecavir 0.5 mg alone for 36-52 weeks, followed by entecavir plus interferon-α for 4 weeks, and lastly by interferon-α alone for 20 weeks. Twenty-three patients had genotype C infection, and one had genotype A infection.

RESULTS

No entecavir-resistant mutant variants emerged in any patient. Hepatitis flare occurred in three patients during interferon-α treatment after the withdrawal of entecavir, but none had hepatic decompensation. Serum hepatitis B surface antigen levels did not change during or after therapy. Serum hepatitis B core-related antigen levels were significantly decreased at the start (P < 0.0001) and at the end of interferon-α treatment (P < 0.0001), but returned to baseline levels after treatment. Twenty-four weeks after the completion of the sequential therapy, a sustained biochemical, virological, and serological response was achieved in 5 (21 %) patients. The proportion of patients in whom HBeAg was lost during entecavir treatment was significantly higher among those with a sustained response than among those with no response (P = 0.015).

CONCLUSIONS

The rate of response to sequential therapy with entecavir and interferon-α in Japanese patients with HBeAg-positive chronic hepatitis B was not higher than the rate in previous studies of lamivudine followed by interferon.

Interferons and their use in persistent viral infections

In 2007, the world celebrated the 50th anniversary of the discovery of interferon (IFN) by Isaacs and Lindenmann. Subsequently, the IFN-alpha gene was cloned, fully sequenced and IFN-alpha was produced in recombinant form. Recombinant IFN-alpha is now used as the basis for treatment of chronic hepatitis C virus infection and can also be used to treat certain forms of chronic hepatitis B virus infections. IFNs have also been used in other viral infections, although with less success. The antiviral mechanisms of IFNs are reviewed in this chapter as well as the utility of IFNs in the treatment of persistent viral infections.