Therapeutic vaccination in chronic hepatitis B: preclinical studies in the woodchuck model

Summary.  Interferon-α and nucleoside analogues are available for the treatment of chronic hepatitis B virus (HBV) infection but do not lead to a satisfactory result. New findings about the immunological control of HBV during acute infection suggest the pivotal role of T-cell mediated immune responses. Several preclinical and clinical trials were undertaken to explore the possibility of stimulating specific immune responses in chronically infected animals and patients by vaccination. However, vaccination with commercially available HBV vaccines in patients and immunization in woodchucks with core or surface proteins of woodchuck hepatitis virus (WHV) did not result in effective control of HBV and WHV infection, suggesting that new formulations of therapeutic vaccines are needed. Some new approaches combining antiviral treatments with nucleoside analogues, DNA vaccines and protein vaccines were tested in the woodchuck model. It could be shown that therapeutic vaccinations are able to stimulate specific B- and T-cell responses and to achieve transient suppression of viral replication. These results suggest the great potential of therapeutic vaccination in combination with antivirals to reach an effective and sustained control of HBV infection.     

关于慢性乙型肝炎抗病毒治疗的几点思考

抗病毒治疗是根治乙型肝炎的关键。以前由于没有有效的抗病毒药物,所以乙型肝炎的治疗一直围绕着“保肝、降酶”进行。直到近年有了干扰素和抗病毒核苷类似物,抗病毒治疗才正式拉开了序幕。几年来抗病毒治疗的临床实践,确实让一些病人获得了长期或短期的缓解。但随着抗病毒药物的推广应用,临床上也逐渐出现了一些问题,使得我们有必要对抗病毒药物的临床价值、使用方法等进行更深入的思考。     

Evolution of hepatitis B virus during long-term therapy in patients with chronic hepatitis B

Background. Long-term lamivudine (LAM), adefovir (ADV) and entecavir (ETV) treatment induce the emergence of drug-resistant hepatitis B virus (HBV) in patients with chronic hepatitis B infection.Aim. To evaluate the LAM, ADV and ETV resistance mutations detected in our patient group.Materials and methods. Twenty patients who had received at least two years of treatment with nucleoside/tide analogues were enrolled in this study. Patients with detectable HBV DNA were analyzed in order to detect resistance mu-tations and in this group of patients treatment was change.Results. Three patients developed LAM resistance mutations (2 presented rtM204I and one rtL180M+rtM204V/I) and one patient showed rtN236T ADV resistance mutation. During ADV and LAM treatment, one patient developed ADV plus LAM resistance mutations (rtI163V+rtL180M+rtA181V+rtN236T), in this case, HBV strains harbouring polymerase mutations did not develop LAM associated rtM204V/I primary mutation. In addition, ETV resistance mutations (rtL180M+rtT184A+rtS202G+rtM204V) were detected in one patient.Conclusions. These findings suggest that monotherapy resulted in a limited virological response and combination strategies including potent antiviral agents should be recommended for patients with resistant mutations.     

Interferon/long-term lamivudine combination therapy in anti-HBe positive chronic hepatitis B patients

BACKGROUND: Monotherapy with a single antiviral agent is insufficient in controlling hepatitis B virus infection in the majority of patients with anti-HBe positive chronic hepatitis B. Interferon/long-term lamivudine combination therapy was evaluated to determine if this strategy would improve treatment efficacy and reduce the emergence of lamivudine resistance. METHODS: In total, 36 consecutive anti-HBe positive patients were treated with interferon (3 MU subcutaneously three times weekly) and lamivudine (100 mg orally once a day) for 12 months. After completion of the combined treatment, all patients continued to receive lamivudine monotherapy indefinitely. RESULTS: Overall, 35 patients (97%) showed virological response at 12 months. Four patients (11%) cleared HBsAg and developed anti-HBs. During the follow-up time, after the discontinuation of interferon, of 30 +/- 12 months (range: 7-57 months), 13 patients (36%) exhibited breakthrough infection. The cumulative rates of breakthrough infection at the end of 1, 2, 3 and 4 years of treatment were 0%, 14%, 32%, and 59%, respectively. CONCLUSIONS: Combination therapy appears to be effective and may also delay the selection of lamivudine-resistant variants. However, controlled trials are definitely warranted to clarify the potential benefits of combination antiviral treatment over monotherapy.     

Therapeutic vaccination in chronic hepatitis B

AIMS: The aim was to test the efficacy of a pre-S2-containing vaccine (Genhevac-B) in chronic hepatitis B (CHB). Twenty-five naive patients (22 male, three female; median age 35; range: 6-69 years) with CHB were recruited. The inclusion criteria were: hepatitis B e antigen (HBeAg) positive or HBV-DNA detectable with liquid hybridization; alanine aminotransferase (ALT) is at least 1.5-fold the upper normal limit and histological evidence of chronic hepatitis. METHODS: In the first period, all patients received monthly injections of 20, 40 and 60 microg of the vaccine. One month after the last injection, patients who still had HBV-DNA were divided into two randomly assigned groups. While the patients in the first group and the patients who lost HBV-DNA in the first period continued to receive monthly injections of 20 microg vaccine for a further 6 months, the patients in the second group received 9 MU interferon alpha-2b (Roferon-A), three times per week using the same method as for the first group. Patients were followed up after 12 months without treatment. Response was defined as the loss of HBV-DNA and normalization of ALT. RESULTS: Six of the 25 patients lost HBV-DNA after 3 months. Nine of the remainder were randomly placed in the first group (vaccine-only) and 10 were placed in the second group (vaccine + interferon). End-of-treatment response was achieved, overall, 8/15 from the vaccine group and 6/10 from the combination. One patient from each group relapsed during the follow up. Overall, the sustained response (SR) rate was 46% (7/15) in the vaccine group, and 50% (5/10) in the combination group. Histological improvement was achieved in 6/7 SR with vaccine-only and all five with combination treatment, while 1/8 of failures of vaccine and 2/5 of failures of combination improved. CONCLUSIONS: It was concluded that Genhevac-B decreases serum HBV-DNA levels in the majority of patients with CHB and sustained clearance was achieved in some patients. Combination of interferon-alpha with Genhevac-B is effective for the vaccine failures and may increase sustained response compared to interferon-alpha alone. However, the mechanism of action is yet to be explained.     

Roadmap to functional cure of chronic hepatitis B: An expert consensus

Hepatitis B virus (HBV) infection continues to be a major public health issue worldwide. HBsAg loss is associated with functional remission and improved long‐term outcome, and is considered to be a ‘functional cure’ (also referred to as clinical or immunologic cure) for chronic hepatitis B. This ideal goal of therapy can be achieved using optimized combination regimens with direct‐acting antivirals [eg nucleos(t)ide analogues (NAs)] and immunomodulators [eg pegylated interferon alpha2a (Peg‐IFN)] in selected patients with chronic hepatitis B. Among different combination therapies currently available, those with NA lead‐in followed by Peg‐IFN in virally suppressed patients has been demonstrated to be effective. This review provides an updated overview of the evidence supporting the use of combination therapies and summarizes expert consensus on the roadmap to attain functional cure for chronic hepatitis B patients.     

Early kidney injury during long-term adefovir dipivoxil therapy for chronic hepatitis B

AIM: To evaluate urine β2-microglobulin(β2-M), retinol-binding protein(RBP) excretion, and renal impairment with adefovir dipivoxil(ADV) for chronic hepatitis B. METHODS: We enrolled 165 patients with chronic hepatitis B infection who were treated with ADV monotherapy(n = 90) or ADV plus lamivudine combination therapy(n = 75). An additional 165 chronic hepatitis B patients treated with entecavir were recruited as controls. We detected serum creatinine, urine β2-M, and RBP levels, and estimated the glomerular filtration rate(e GFR) at the initiation of antiviral therapy and every 6 mo for a period of five years. RESULTS: Urine β2-M abnormalities were observed in patients during the first(n = 3), second(n = 7), third(n = 11), fourth(n = 16), and fifth(n = 21) year of ADV treatment. Urinary RBP abnormalities were observed in patients during the first(n = 2), second(n = 8), third(n = 12), fourth(n = 15), and fifth(n = 22) year of ADV treatment. e GFR decreased 20%-30% from baseline in 20 patients, 30%-50% in 12 patients, and > 50% in 3 patients during the five years of treatment. Further analysis indicated that decreases in e GFR of ≥ 30% relative to the baseline level correlated significantly with urine RBP and β2-M abnormalities. In contrast, both serum creatinine and e GFR remained stable in patients treated with entecavir, and only one of these patients developed a urine β2-M abnormality, and two developed urine RBP abnormalities during the five years of treatment. CONCLUSION: Urine RBP and β2-M are biomarkers of renal injury during long-term ADV treatment for chronic hepatitis B, and indicate when treatment should be switched to entecavir.     

Randomised controlled trial: effect of metformin add-on therapy on functional cure in entecavir-treated patients with chronic hepatitis B

Introduction and ObjectivesHepatitis B surface antigen (HBsAg) clearance, indicating functional cure or resolved chronic hepatitis B (CHB), remains difficult to achieve via nucleos(t)ide analogue monotherapy. We investigated whether metformin add-on therapy could help achieve this goal in entecavir-treated patients with hepatitis B e antigen (HBeAg)-negative CHB.Patients and MethodsPatients with HBeAg-negative CHB who met eligibility criteria (entecavir treatment for > 12 months, HBsAg < 1000 IU/mL) were randomly assigned (1:1) to receive 24 weeks of either metformin (1000 mg, oral, once a day) or placebo (oral, once a day) add-on therapy. The group allocation was blinded for both patients and investigators. Efficacy and safety analyses were based on the intention-to-treat set. The primary outcome, serum HBsAg level (IU/mL) at weeks 24 and 36, was analysed using mixed models.ResultsSixty eligible patients were randomly assigned to the metformin (n = 29) and placebo (n = 31) groups. There was no substantial between-group difference in the HBsAg level at week 24 (adjusted mean difference 0.05, 95% confidence interval -0.04 to 0.13, p = 0.278) or week 36 (0.06, -0.03 to 0.15, p = 0.187), and no significant effect of group-by-time interaction on the HBsAg level throughout the trial (p = 0.814). The occurrence of total adverse events between the two groups was comparable (9 [31.0%] of 29 vs. 5 [16.1%] of 31, p = 0.227) and no patient experienced serious adverse events during the study.ConclusionAlthough it was safe, metformin add-on therapy did not accelerate HBsAg clearance in entecavir-treated patients with HBeAg-negative CHB.     

Short- and long-term outcome of interferon therapy for chronic hepatitis B infection

Hepatitis B virus (HBV) infection is a serious clinical problem worldwide. Conventional interferon (IFN)-α has been approved for the treatment of chronic hepatitis B (CHB). Short-term studies have demonstrated that IFN-based therapy is moderately effective in inducing the loss of hepatitis e antigen (HBeAg) or seroconversion (30%-40%) in HBeAg-positive patients and also produces sustained HBV DNA suppression (20%-30%) in HBeAg-negative patients. Many studies have reported a correlation between the HBV genotype and response to IFN treatment. The highest response rate to IFN treatment was found in patients infected with HBV genotype A, followed by HBV genotypes B, C, and D. The long-term effect of IFN-α on CHB has not yet been elucidated. The ability of IFN-α treatment to prevent new cirrhosis, complications associated with cirrhosis, and development of hepatocellular carcinoma (HCC) is controversial. The beneficial effect of IFN-α treatment in reducing the development of HCC has mainly been observed in treatment responders who already have cirrhosis. These inconsistent findings may be attributed to the inevitable limitations of comparisons across studies, including differences in the baseline characteristics of the study and the moderate suppression of HBV replication by IFN-α relative to nucleoside/nucleos(t)ide analogs.     

Interferon therapy for chronic hepatitis B

This article summarizes the results obtained with interferon alfa and pegylated interferon alfa, as monotherapy and in combination with lamivudine, in the treatment of chronic hepatitis B.     

慢性乙型肝炎联合抗病毒治疗研究进展

抗病毒治疗是慢性乙型肝炎治疗的重要手段。目前单一药物的疗效不令人满意,越来越多的研究数据表明药物联合抗病毒治疗,包括干扰素α和核苷（酸）类似物联合治疗以及两种核苷（酸）类似物联合治疗可以减少耐药发生、提高抗病毒疗效,因而联合抗病毒治疗可能是控制乙肝的有效策略。     

慢性乙型肝炎抗病毒治疗新进展

慢性乙型肝炎是由乙型肝炎病毒感染引起的、以肝脏炎症和坏死病变为主的一种全身性感染病。目前,治疗乙型肝炎的抗病毒药物主要包括干扰素和核苷酸类似物两类。现在正在探索开发新药及优化联合、免疫疗法或凋亡疗法（促进感染细胞凋亡）来彻底根除慢性HBV 感染。     

Advances in therapy for chronic hepatitis B

Two agents are currently approved for the treatment of chronic hepatitis B: interferon alfa and lamivudine. Each agent has inherent limitations for use in the treatment of chronic hepatitis B. Interferon alfa is effective in a small number of patients and has serious side effects that limit its tolerability. The efficacy of lamivudine is limited by the emergence of drug-resistant hepatitis B virus (HBV) mutants, restricting its utility as a long-term therapy for chronic hepatitis B. As a result, a large proportion of chronic hepatitis B patients continue to be in need of a safe and efficacious therapy. This article provides an integrated analysis of the safety and efficacy of a new nucleotide analogue, adefovir dipivoxil, based on emerging data from recent studies. The study groups include patients with hepatitis B e antigen (HBeAg)-positive and HBeAg-negative chronic hepatitis B; lamivudine-resistant patients with compensated liver disease; lamivudine-resistant patients coinfected with the human immunodeficiency virus (HIV); and lamivudine-resistant pretransplant and posttransplant patients with decompensated liver disease. Adefovir dipivoxil 10 mg/d demonstrated potent anti-HBV activity consistently across this broad range of patient populations and was well-tolerated. Adefovir dipivoxil's effects include rapid and sustained virological, serological, histological, and biochemical responses, with minimal adverse effects. Significant histological improvement was seen in all patient subgroups at 48 weeks.     

慢性乙型肝炎的干扰素治疗

慢性乙型肝炎已成为全球一个严重的健康问题.HBV慢性感染者可发展为肝硬化、失代偿肝病以及肝细胞肝癌.抗病毒治疗是慢性乙型肝炎最关键的治疗方法,持续抑制或清除HBV可改善肝脏炎症及纤维化,降低HBV相关并发症.目前公认有效的抗HBV药物主要包括干扰素和核苷酸类似物.     

Antiplatelet therapy prevents hepatocellular carcinoma and improves survival in a mouse model of chronic hepatitis B

Chronic infection with hepatitis B virus (HBV) is a major risk factor for the development of hepatocellular carcinoma (HCC). The pathogenesis of HBV-associated HCC involves both viral and host factors. The latter include a functionally inefficient CD8(+) T-cell response that fails to clear the infection from the liver but sustains a chronic necroinflammatory process that contributes to the development of HCC. According to this scenario, amelioration of immune-mediated chronic liver injury may prevent HCC. Because platelets facilitate immune-mediated liver injury by promoting the hepatic accumulation of virus-specific CD8(+) T cells, we evaluated the long-term consequences of antiplatelet therapy in an HBV transgenic mouse model of chronic immune-mediated necroinflammatory liver disease that progresses to HCC. Treatment with aspirin and clopidogrel during the chronic phase of the disease diminished the number of intrahepatic HBV-specific CD8(+) T cells and HBV-nonspecific inflammatory cells, the severity of liver fibrosis, and the development of HCC. Antiplatelet therapy improved overall survival without causing significant side effects. In contrast, the same antiplatelet regimen had no antitumor effect when HCC was induced nonimmunologically by chronic exposure to a hepatotoxic chemical. The unprecedented observation that antiplatelet therapy inhibits or delays immune-mediated hepatocarcinogenesis suggests that platelets may be key players in the pathogenesis of HBV-associated liver cancer and supports the notion that immune-mediated necroinflammatory reactions are an important cause of hepatocellular transformation during chronic hepatitis.     

慢性乙型肝炎初治患者的抗病毒优化治疗

近十几年来,慢性乙型肝炎的抗病毒治疗研究取得了令人瞩目的进展,随着核苷(酸)类似物等药物的逐个研发和争相面市,临床获益甚多.这些药物能有效抑制病毒复制,从而控制疾病进展,显著改善预后,大大降低了与HBV感染相关的肝硬化和肝癌的发生率.但在经历了这段快速发展之后,相关研究的步伐明显减缓,很久没有听见能让人振奋的喜讯,当前正面临着抗病毒治疗发展的"瓶颈",期待有新的突破.以往的新药临床研究基本上按单药、方案不变的原则设计,临床治疗方案也按这种研究结果推荐,尽管大多数患者能受益,但也有少数应答不佳的患者因没有可供及时和有效调整的方案导致治疗失败或中断治疗.而且,以往大多数研究注重治疗过程中是否应答,继续治疗是否维持应答,并不注重停药后是否持续应答,于是强调长期治疗.因此,目前抗病毒治疗的现状可被简单概括为"三易三难",即"用药容易停药难,病毒控制容易免疫控制难,标准治疗容易个体化治疗难",克服"三难"、突破"瓶颈"是当前面临的主要任务,是研究的热点,可能的解决途径之一是深入进行"优化治疗"的研究.     

双环醇在慢性乙型肝炎联合治疗中的应用

目前普遍认为,HBV病毒水平是慢性乙型肝炎病程转归的决定因素,因此抗病毒治疗正成为慢性乙型肝炎治疗的主流趋势;同时,病理生理机制研究目前还不能完全清楚地揭示肝脏炎症触发后的确切变化过程,传统的非特异性抗炎治疗逐渐被边缘化。干扰素和核苷（酸）类似物的应用使得血清病毒标志物和HBVDNA水平有了改善,但在慢性乙型肝炎的治疗方面,仍然存在缺憾：现有抗病毒药物,无论干扰素类或核苷（酸）类似物类,对HBV的控制均不能达到令人满意的效果;