Role of lamivudine in the posttransplant prophylaxis of chronic hepatitis B virus and hepatitis delta virus coinfection

EASL Clinical Practice Guidelines on hepatitis delta virus

Hepatitis D virus (HDV) is a defective virus that requires the hepatitis B virus to complete its life cycle and cause liver damage in humans. HDV is responsible for rare acute and chronic liver diseases and is considered the most aggressive hepatitis virus. Acute infection can cause acute liver failure, while persistent infection typically causes a severe form of chronic hepatitis which is associated with rapid and frequent progression to cirrhosis and its end-stage complications, hepatic decompensation and hepatocellular carcinoma. Major diagnostic and therapeutic innovations prompted the EASL Governing Board to commission specific Clinical Practice Guidelines on the identification, virologic and clinical characterisation, prognostic assessment, and appropriate clinical and therapeutic management of HDV-infected individuals.

The Role of Antiviral Prophylaxis in Preventing HBV and HDV Recurrence in the Setting of Liver Transplantation

Hepatitis B virus (HBV) is a prevalent underlying disease, leading to liver transplantation (LT) for both decompensated cirrhosis and hepatocellular carcinoma (HCC). The hepatitis delta virus (HDV) affects approximately 5-10% of HBsAg carriers, accelerating the progression of liver injury and HCC. The initial introduction of HBV immunoglobulins (HBIG), and then of nucleos(t)ide analogues (NUCs), considerably improved the survival of HBV/HDV patients post-transplantation, as they helped prevent re-infection of the graft and recurrence of liver disease. Combination therapy with HBIG and NUCs is the primary post-transplant prophylaxis strategy in patients transplanted for HBV- and HDV-related liver disease. However, monotherapy with high-barrier NUCs, such as entecavir and tenofovir, is safe and also effective in some individuals who are at low risk of HBV reactivation. To address the problems of organ shortage, last-generation NUCs have facilitated the use of anti-HBc and HBsAg-positive grafts to meet the ever-increasing demand for grafts.

2020 position statement and recommendations of the European Liver and Intestine Transplantation Association (ELITA): management of hepatitis B virus-related infection before and after liver transplantation

BACKGROUND

Prophylaxis of HBV recurrence is critical after liver transplantation in HBV patients. Despite new prophylactic schemes, most European LT centres persist on a conservative approach combining hepatitis B immunoglobulin (HBIG) and nucleos(t)ides analogues (NA).

AIM

This setting prompted the European Liver Intestine Transplantation Association (ELITA) to look for a consensus on the prevention of HBV recurrence.

METHODS

Based on a 4-round Delphi process, ELITA investigated 16 research questions and established 50 recommendations.

RESULTS

Prophylaxis should be driven according to 3 simplified risk groups: Low and high virological risk patients, with undetectable and detectable HBV DNA pre-LT, respectively, and special populations (HDV, HCC, poorly adherent patients). In low-risk patients, short-term (4 weeks) combination of third-generation NA+ HBIG, or third generation NA monotherapy can be considered as prophylactic options. In high-risk patients, HBIG can be discontinued once HBV DNA undetectable. Combined therapy for 1 year is advised. HBV-HCC patients should be treated according to their virological risk. In HDV/HBV patients, indefinite dual prophylaxis remains the gold standard. Full withdrawal of HBV prophylaxis following or not HBV vaccination should only be attempted in the setting of clinical trials. Organs from HBsAg+ve donors may be considered after assessment of risks, benefits, and patient consent. They should not be used if HDV is present. In poorly adherent patients, dual long-term prophylaxis is recommended. Budget impact analysis should be taken into account to drive prophylactic regimen.

CONCLUSIONS

These ELITA recommendations should stimulate a more rational and homogeneous approach to HBV prophylaxis across LT programs.

Immunoglobulin, nucleos(t)ide analogues and hepatitis B virus recurrence after liver transplant: A meta-analysis

BACKGROUND

Prophylaxis with hepatitis B immunoglobulin (HBIG) represents an efficient strategy for reducing the risk of hepatitis B virus (HBV) recurrence after liver transplantation (LT). Unfortunately, the long-term use of HBIG presents high costs. Therefore, the use of prophylaxis based only on nucleos(t)ide analogues (NUC) has been recently postulated. The present meta-analysis aimed to evaluate the impact of HBIG ± NUC vs HBIG alone or NUC alone in post-LT HBV recurrence prophylaxis.

MATERIALS AND METHODS

A systematic literature search was performed using PubMed and Cochrane databases. The primary outcome investigated was the HBV recurrence after LT. Three analyses were done comparing the effect of (a) HBIG + NUC vs HBIG alone; (b) HBIG+NUC vs NUC alone; and (c) HBIG alone vs NUC alone. Sub-analyses were also performed investigating the effect of low and high genetic barrierto-recurrence NUC.

RESULTS

Fifty-one studies were included. The summary OR (95%CI) showed a decreased risk with the combination of HBIG + NUC vs HBIG alone for HBV recurrence, being 0.36 (95% CI = 0.22-0.61; P < .001). HBIG + NUC combined treatment reduced HBV reappearance respect to NUC alone (OR = 0.22; 95% CI = 0.16-0.30; P < .0001). Similarly, HBIG alone was significantly better than NUC alone in preventing HBV recurrence (OR = 0.20; 95% CI = 0.09-0.44; P < .0001).

CONCLUSIONS

Prophylaxis with HBIG is relevant in preventing post-LT HBV recurrence. Its combination with NUC gives the best results in terms of protection. The present results should be considered in light of the fact that also old studies based on lamivudine use were included. Studies exploring in detail high genetic barrier-to-recurrence NUC and protocols with definite use of HBIG are needed.

Antiviral prophylaxis against hepatitis B recurrence after liver transplantation: Current concepts

The advance in treatment against hepatitis B virus (HBV) infection with the development of nucleos(t)ide analogues (NAs) with high genetic barrier to resistance, including entecavir and tenofovir, has improved clinical outcomes of patients transplanted for HBV infection, by preventing HBV recurrence after liver transplantation (LT) effectively. Currently, after LT, the combination of hepatitis B immunoglobulin (HBIG) and a high-barrier NA is considered as the standard of care for prophylaxis against HBV recurrence. However, because of the high cost of intravenous high-dose HBIG, other routes of HBIG administration, such as intramuscular or subcutaneous, have come to the foreground. In addition, several transplant centres tend to use a NA as monoprophylaxis, following a short post-LT period of HBIG and NA combination. Lately, studies using HBIG-free prophylactic regimens with entecavir or tenofovir have shown promising outcomes in preventing HBV recurrence, mostly regarding patients with undetectable HBV DNA at the time of LT. Although vaccination against HBV has been an attractive prophylactic approach, its efficacy has been controversial. Moreover, further studies are needed regarding long-term outcomes of complete withdrawal anti-HBV prophylaxis. For patients transplanted for HBV/HDV co-infection, combined regimen should be administered for a longer period post-LT. Finally, the use of grafts from hepatitis B core antibody-positive donors is safe for HBV-negative recipients, with the administration of lifelong antiviral prophylaxis.

Nucleos(t)ide analog(s) prophylaxis after hepatitis B immunoglobulin withdrawal against hepatitis B and D recurrence after liver transplantation

BACKGROUND/AIMS

Nucleos(t)ide analogs (NAs) have made a hepatitis B immunoglobulin (HBIG)-sparing protocol an attractive approach against hepatitis B virus (HBV) recurrence after liver transplantation (LT). However, this approach is considered controversial in patients transplanted for HBV and hepatitis D (HDV) co-infection.

MATERIAL/METHODS

All patients transplanted for HBV/HDV cirrhosis were evaluated. After LT, each patient received HBIG + NAs and then continued with NAs prophylaxis. All patients were followed up with HBV serum markers and HBV DNA, while anti-HDV/HDV RNA was performed in those with HBV recurrence.

RESULTS

A total of 34 recipients were included (22 men, age: 46.7 ± 16 years). After HBIG discontinuation, NAs were received as monoprophylaxis (lamivudine [LAM]: 2, adefovir [AFV]: 1, entecavir: 9, tenofovir [TDF]: 12) or dual prophylaxis (LAM + AFV [or TDF]: 10 patients). Two (5.8%) of the 34 patients had HBV/HDV recurrence after HBIG withdrawal (median follow-up: 28 [range, 12-58] months). These 2 patients had undetectable HBV DNA at LT. Statistical analysis revealed that those with recurrence had received HBIG for shorter period, compared to those without recurrence (median: 9 vs. 28 months, P = 0.008).

CONCLUSIONS

We showed for the first time, to our knowledge, that maintenance therapy with NAs prophylaxis after HBIG discontinuation was effective against HBV/HDV recurrence, but it seems that a longer period of HBIG administration might be needed before it is withdrawn after LT.

The long-term efficacy of combining nucleos(t)ide analog and low-dose hepatitis B immunoglobulin on post-transplant hepatitis B virus recurrence

BACKGROUND

The aim of this study was to determine the long-term efficacy of nucleos(t)ide analog (NA) and low-dose hepatitis B immunoglobulin (HBIG) combination treatment for preventing post-transplant hepatitis B virus (HBV) recurrence.

METHODS

A total of 296 patients with HBV-associated liver disease who underwent liver transplantation (LT) were enrolled. A combination of a daily NA and low-dose HBIG was used after LT.

RESULTS

The median follow-up period was 46 months. HBV recurrence occurred in eight patients. The cumulative probability of HBV recurrence at 1, 3, 5, and 7 years was 1%, 3%, 3%, and 4%, respectively. Seven were on lamivudine (LMV) or adefovir dipivoxil (ADV), or LMV and ADV and HBIG combination treatment and one entecavir (ETV) and HBIG. With Cox regression analysis, HBV recurrence was determined to be associated with the presence of hepatocellular cancer (HCC) prior to LT (HR: 12.3, P=.02). Overall, 44 patients died. Survival was significantly better in the ETV or tenofovir disoproxil fumarate (TDF) and HBIG group than the other group (P<.001).

CONCLUSION

The combination of ETV or TDF and low-dose HBIG achieved a more favorable prophylaxis against HBV recurrence after LT. The presence of HCC prior to LT was associated with post-transplant HBV recurrence.

Liver transplantation for hepatitis B virus: Decreasing indication and changing trends

AIM: To evaluate the indication and outcome of hepatitis B virus (HBV)-related liver transplantation (LT) in the era of newer antiviral agents.

METHODS: We collected data on all patients who underwent transplantation at King Faisal Specialist Hospital and Research Center. These data included demographic, perioperative and long-term postoperative follow-up data including viral serological markers, HBV DNA, and repeated liver imaging. Between January 1990 and January 2012, 133 patients (106 males and 27 females) underwent LT for HBV-related cirrhosis at our center. All patients were followed up frequently during the first year following transplantation, according to our standard protocol; follow-up visits occurred every 3-6 mo thereafter. Breakthrough infection was defined as re-emergence of HBV-DNA or hepatitis B surface antigen (HBsAg) while on treatment. Five patients transplanted prior to 1992 did not receive immediate posttransplant anti-HBV prophylaxis; all other patients were treated with HBIG and at least one nucleos(t)ide analog.

RESULTS: One hundred and thirty-three patients underwent LT for HBV and were followed for a median of 82 mo (range: 1-274). The rates of post-LT survival and HBV recurrence during the follow-up period were 89% and 11%, respectively. The following factors were associated with disease recurrence: younger age (44.3 ± 16.2 years vs 51.4 ± 9.9 years, P = 0.02), positive pretransplant hepatitis B e antigen (HBeAg) (60% vs 14%, P < 0.0001), detectable pretransplant HBV DNA (60% vs 27%, P = 0.03), positive posttransplant HBsAg (80% vs 4%, P < 0.0001) and positive posttransplant HBeAg (27% vs 1%, P < 0.0001). Forty-four (33%) patients had hepatocellular carcinoma (HCC). In the first (pre-2007) group, HBV was the second leading indication for LT after hepatitis C virus infection. A total of 64 transplants were performed, including 46 (72%) for decompensated HBV cirrhosis, 12 (19%) for decompensated cirrhosis complicated by HCC and 6 (10%) for compensated cirrhosis complicated by HCC. In the second group, nonalcoholic steatohepatitis surpassed HBV as the second leading indication for LT. A total of 69 HBV related transplants were performed, including 43 (62%) for decompensated HBV cirrhosis, 7 (10%) for decompensated cirrhosis complicated by HCC and 19 (27.5%) for compensated cirrhosis complicated by HCC. There was a significant (P = 0.007) increase in the number of transplants for compensated cirrhosis complicated by HCC.

CONCLUSION: The use of potent anti-HBV agents has led to a changing trend in the indications for LT. HBV is currently the third leading indication for LT in this hyperendemic area.

Treatment of delta hepatitis

Hepatitis delta virus (HDV) is a defective RNA virus that depends on hepatitis B virus (HBV) for its lifecycle. Treatment of chronic HDV infection is difficult as it does not have an enzymatic function as a target, such as polymerases and proteases of HBV and hepatitis C virus. Recently, it has been suggested that farnesyl transferase could be an enzymatic target. Currently, interferon is the only agent against HDV infection. Virological response has risen to 20-47% with pegylated interferon. Monotherapy of nucleos(t)ide analogs are ineffective against the HDV infection, but adefovir and pegylated interferon combination therapy have had some advantages for reduction of HBV surface antigen (HBsAg) levels. Recent studies suggest that measuring HBsAg levels during treatment could be more meaningful than HDV RNA negativity to predict virological response. Prenylation inhibitors that can affect the interactions between the large HDV antigen and HBsAg in the HDV virion are expected treatments for HDV infection. More studies are needed to understand the molecular mechanisms of HDV to manage the disease.

Efficacy, safety, and pharmacokinetics of intramuscular hepatitis B immune globulin, Igantibe, for the prophylaxis of viral B hepatitis after liver transplantation

BACKGROUND

Long-term prophylaxis of hepatitis B virus (HBV) positive liver transplanted subjects with intravenous hepatitis B immunoglobulin (HBIG) is effective, however use of intramuscular HBIG could be as effective with fewer adverse events and lower cost.

AIM

We conducted a prospective, non-randomized, clinical study to assess the efficacy and safety of HBIG from Grifols, Igantibe, for the prophylaxis of HBV reactivation.

METHODS

Eighteen adult patients submitted to liver transplantation for HBV-related disease more than 18 months earlier were treated with doses of 2000 I.U. intramuscular Igantibe every 14 days for 6 months.

RESULTS

Mean trough serum HBsAb IgG titers from months 4 to 6 (primary efficacy variable) were protective (>or=150 I.U./L) at each time point. Individual measurements were also protective throughout the study. HBV replication remained negative for all available subjects until study completion. Pharmacokinetic analysis showed a half-life of 27 days and extensive exposure to the study drug. Safety and tolerability of intramuscular Igantibe were good, with only one adverse event.

CONCLUSION

Standard-dose intramuscular Igantibe administration proved efficacious in post-liver transplantation prophylaxis by attaining protective levels for up to 6 months, was safe and well tolerated. Pharmacokinetic analysis revealed a long half-life and extensive exposure.

Prevention of recurrent hepatitis B virus infection after liver transplantation: hepatitis B immunoglobulin, antiviral drugs, or both? Systematic review and meta-analysis

OBJECTIVES

To evaluate antiviral prophylaxis against hepatitis B virus (HBV) following liver transplantation.

METHODS

Systematic review and meta-analysis. Clinical trials and comparative cohort studies comparing the use of hepatitis B immunoglobulin (HBIg), antivirals, or both following liver transplantation for HBV infection were included. The primary outcome was reappearance of hepatitis B surface antigen (HBsAg). Other outcomes included all-cause and HBV-related mortality, HB-related active liver disease, and reappearance of HBV DNA after transplantation. Relative risks (RR) with 95% confidence intervals (CIs) are reported.

RESULTS

Twenty studies (22 comparisons) were included. Ten studies compared HBIg to combination treatment, 9 compared antivirals to combination treatment, and 3 compared lamivudine (LAM) to HBIg. Combination treatment reduced HBsAg reappearance (RR 0.28; 95% CI 0.12-0.66), and was superior to HBIg alone in all other outcome measures. Combination treatment was significantly better than antivirals in preventing reappearance of HBsAg (RR 0.31; 95% CI 0.22-0.44), even when low-dose HBIg was given. No significant difference was found between HBIg and LAM monotherapy for all measured outcomes. Major limitations with regard to comparability of the study groups in non-randomized trials were revealed.

CONCLUSIONS

Combination treatment with HBIg and LAM reduced HBV recurrence following liver transplantation, compared with HBIg or LAM alone, and reduced mortality compared with HBIg alone.

Effect of β-L-D4A on human DNA polymerases β and δ and its mechanism

AIM: To purify and characterize the DNA polymerase δ and investigate the side effects of β-L-D4A (a novel nucleoside analog) on human DNA polymerases β and δ.

METHODS: Human DNA polymerase δ was separated from crude extract of human Hela cells by ion exchange chromatography. Detailed kinetic parameters were determined for β-L-D4A against DNA polymerases β and δ.

RESULTS: Human DNA polymerase δ was purified and characterized with a yield of 15% and a specific activity of 1911 Ukat/mg. When β-L-D4A was used as an inhibitor, the kinetic parameters of human DNA polymerases β and δ were Km = 1.86 μmol/L and 2.45 μmol/L, IC₅₀ = 25.21 μmol/L and 150.1 μmol/L, Ki = 24.03 μmol/L and 132.7 μmol/L, respectively, suggesting that the inhibitory effect of β-L-D4A on human DNA polymerases β and δ was less than that of lamivudine.

CONCLUSION: β-L-D4A is a competitive inhibitor of DNA polymerases β and δ. Its toxic side effects on DNA polymerases β and δ are less than lamivudine. It can be expected to become a high efficient and low toxic anti-HBV agent.

Effect and mechanism of β-L-D4A on DNA polymerase α

AIM: To investigate the safety of β-L-D4A on DNA polymerase α.

METHODS: Ion exchange chromatography was used to separate DNA polymerase α from crude extract of human Hela cells. Detailed kinetic parameters were determined for β-L-D4A against DNA polymerase α.

RESULTS: DNA polymerase α was purified with 4% yield and 31 000 units/mg specific activity. The Michaelis constant (Km = 3.22 μmol/L), 50% inhibition concentration (IC50 = 178.49 μmol/L) and inhibition constant (Ki = 126 μmol/L) of β-L-D4A were determined by kinetic analysis.

CONCLUSION: β-L-D4A is a more safe nucleoside for hepatitis B virus (HBV) infection with a lower host toxicity.