Entecavir: a potent antiviral with minimal long-term resistance in nucleoside-naive chronic hepatitis B patients

Entecavir Monotherapy Prevents Hepatitis B Virus Recurrence After Liver Transplant for Chronic Hepatitis B Patients: A Long-Term Retrospective Study

BACKGROUND

Limited data are available on the use of oral antiviral therapy, particularly the long-term use of entecavir monotherapy in patients with hepatitis B virus (HBV)-related diseases after liver transplant (LT).

METHODS

The clinical data on consecutive patients who underwent LT for HBV-related diseases from 2011 to 2019 were prospectively collected and retrospectively analyzed. All patients received entecavir monotherapy alone during the follow-up period; viral serology/load and liver biochemical tests were performed regularly.

RESULTS

Among the total of 89 patients were patients with decompensated cirrhosis (n = 27 [30%]), acute-on-chronic HBV (n = 21 [24%]), and hepatocellular carcinoma (HCC) (n = 41 [46%]). The median age of the patients was 50 years (range, 42-58 years), and the median follow-up was 37 months (range, 1-96 months). Before LT, 45 (51%) patients did not receive, whereas 44 (49%) were currently receiving, oral antiviral therapy. At the time of LT, serum level of HBV DNA of 34 (38%) patients was >20 IU/mL, with the median level being 270,000 IU/mL (range, 4270-2,020,000), and 53 patients (59%) had undetectable levels of HBV DNA (≤20 IU/mL). The cumulative rate of hepatitis B surface antigen loss was 79.8%, 100%, and 100% after 1 month, 1 year, and 5 years, respectively. Hepatitis B surface antigen positivity returned after seroclearance in 1 patient, who died of HCC recurrence with an undetectable level of HBV DNA. The overall survival rates at 1, 3, and 5 years after LT were 94.51%, 86.84%, and 85.27%, respectively. During the follow-up period, no entecavir adverse reactions or dose reductions were observed.

CONCLUSIONS

Long-term entecavir monotherapy was highly effective in preventing HBV reactivation and HBV-related diseases.

Efficacy and Safety of Entecavir 0. 5 mg in Treating Naive Chronic Hepatitis B Virus Patients in Egypt: Five Years of Real Life Experience

Background

The aim of the study was to evaluate the efficacy and safety of entecavir (ETV) among chronic hepatitis B (CHB) nucleos(t)ide-naive Egyptian patients.

Methods

Forty-eight CHB patients on ETV were included. Males comprised 83.3% (40 cases), while females comprised 16.7% (eight cases). Minimum age was 19 years, while maximum age was 64 years. Hepatitis B envelope antigen (HBeAg)-negative cases were 60.4%. HBeAg-positive cases were 39.6%. Factors including sex, positive HBeAg, baseline hepatitis B virus (HBV) DNA level, baseline alanine aminotransferase (ALT) and aspartate aminotransferase (AST), were evaluated in terms of their predictive role in treatment response, which was defined as a serum HBV DNA decrease of < 10 IU/mL.

Results

Mean age of patients was 38.2 years; males were 83.3% and females were 16.7%. HBeAg-negative cases were 60.4%, while HBeAg-positive cases were 39.6%. Mean baseline DNA level was 44 × 10⁶ IU/mL. Ultrasound results showed 14 cases had hepatomegaly, 10 cases had bright liver, seven cases had coarse liver, and eight cases had cirrhosis. Of the cases, 45.8% showed a negative PCR after the first 6 months of therapy to reach 64.6% by the end of the first year. HBV DNA undetectability reached 91.3% and 100% after 4 and 5 years, respectively for those who completed the study period. ALT reduction started after 6 months of treatment and reached 53.37% after 5 years. Similarly AST showed the same pattern of decline and reached 54.37% after 5 years. Only two cases achieved HBeAg seroconversion. Three patients experienced virological breakthrough and the three cases shared similar characteristics of being less than 40 years, with baseline HBV DNA of ≥ 10⁵ IU/mL and positive HBeAg. None of the cases showed hepatitis B surface antigen (HBsAg) seroconversion.

Conclusion

ETV proved to have a potent antiviral efficacy and safety in nucleoside/tide-naive Egyptian patients. Rate of HBV DNA undetectability was higher in patients above 40 years of age and in patients who initially had a low viral load. ETV was well tolerated during the treatment period with a good overall safety profile.

Comparison of the Efficacy of Tenofovir Versus Tenofovir plus Entecavir in the Treatment of Chronic Hepatitis B in Patients With Poor Efficacy of Entecavir: A Systematic Review and Meta-analysis

PURPOSE

This study aimed to compare the efficacy between tenofovir disoproxil fumarate (TDF) and TDF plus entecavir (ETV) combination therapy in patients with chronic hepatitis B (CHB) with a poor response to ETV.

METHODS

We searched the China National Knowledge Infrastructure (CNKI), PubMed, EMBASE, and SCOPE libraries for articles using the keywords chronic hepatitis B virus or CHB or HBV, entecavir or ETV, and tenofovir or TDF.

FINDINGS

Five studies (from CNKI and PubMed) with a total of 408 patients met the inclusion criteria: 212 patients in the TDF group and 196 patients in the TDF plus ETV group. The rates of viral suppression between the 2 groups were comparable at weeks 24 and 48 of treatment (P = 0.546 vs P = 0.818). In addition, the subanalysis revealed that no significant differences were observed in the rates of viral suppression between the 2 groups at week 24 (subgroup 1 [partial response to ETV]: P = 0.822; subgroup 2 [resistance to ETV]: P = 0.294) and week 48 (subgroup 1: P = 0.797; subgroup 2: P = 0.545). No significant differences were found in alanine aminotransferase normalization, hepatitis B e antigen loss, hepatitis B e antigen seroconversion, virologic breakthrough, and tolerability between the 2 groups at weeks 24 and 48. Therefore, the results suggest that TDF monotherapy should be chosen for patients with CHB with a poor response to ETV for reasons of economy and convenience.

IMPLICATIONS

We conclude that TDF monotherapy is comparable to TDF-ETV combination therapy for patients with a poor response to ETV; thus, TDF monotherapy may be a better choice for these patients. However, because of the limited citations in this meta-analysis, complete and systematic evidence is needed to evaluate the differences in efficacy and tolerability between TDF and TDF-ETV. Larger and longer randomized clinical trials and further studies should be conducted to verify the results.

Multiple Drug Transporters Are Involved in Renal Secretion of Entecavir

Entecavir (ETV) is a first-line antiviral agent for the treatment of chronic hepatitis B virus infection. Renal excretion is the major elimination path of ETV, in which tubular secretion plays the key role. However, the secretion mechanism has not been clarified. We speculated that renal transporters mediated the secretion of ETV. Therefore, the aim of our study was to elucidate which transporters contribute to the renal disposition of ETV. Our results revealed that ETV (50 μM) remarkably reduced the accumulation of probe substrates in MDCK cells stably expressing human multidrug and toxin efflux extrusion proteins (hMATE1/2-K), organic cation transporter 2 (hOCT2), and carnitine/organic cation transporters (hOCTNs) and increased the substrate accumulation in cells transfected with multidrug resistance-associated protein 2 (hMRP2) or multidrug resistance protein 1 (hMDR1). Moreover, ETV was proved to be a substrate of the above-described transporters. In transwell studies, the transport of ETV in MDCK-hOCT2-hMATE1 showed a distinct directionality from BL (hOCT2) to AP (hMATE1), and the cellular accumulation of ETV in cells expressing hMATE1 was dramatically lower than that of the mock-treated cells. The accumulation of ETV in mouse primary renal tubular cells was obviously affected by inhibitors of organic anion transporter 1/3 (Oat1/3), Oct2, Octn1/2, and Mrp2. Therefore, the renal uptake of ETV is likely mediated by OAT1/3 and OCT2 while the efflux is mediated by MATEs, MDR1, and MRP2, and OCTN1/2 may participate in both renal secretion and reabsorption.

Synthesis and quantitative structure-activity relationships study for phenylpropenamide derivatives as inhibitors of hepatitis B virus replication

A series of new phenylpropenamide derivatives containing different substituents was synthesized, characterized and evaluated for their anti-hepatitis B virus (HBV) activities. The quantitative structure-activity relationships (QSAR) of phenylpropenamide compound have been studied. The 2D-QSAR models, based on DFT and multiple linear regression analysis methods, revealed that higher values of total energy (TE) and lower entropy (S(ө)) enhanced the anti-HBV activities of the phenylpropenamide molecules. Predictive 3D-QSAR models were established using SYBYL multifit molecular alignment rule. The optimum models were all statistically significant with cross-validated and conventional coefficients, indicating that they were reliable enough for activity prediction.

Recent advances in prevention of hepatitis B recurrence after liver transplantation

Liver transplantation is the only effective treatment for hepatitis B virus (HBV)-related end-stage liver disease. However, without antiviral prophylaxis, the recurrence rate of hepatitis B is as high as 80%-100%, which leads to a 50% mortality rate in the first 2 years after liver transplantation. Combination therapy of hepatitis B immunoglobulin (HBIG) and lamivudine demonstrated a higher efficacy of prophylaxis and further reduced the rate of recurrence to < 10%. The strategy of HBIG combined with lamivudine has been the standard treatment in many centers. However, the high rate of lamivudine resistance and the many disadvantages of HBIG have compelled surgeons to reconsider the long-term efficacy of this strategy for the prevention of HBV reinfection. Recently, new nucleos(t)ide analogues, such as entecavir and tenofovir, have been approved as first-line monotherapies for the treatment of chronic hepatitis B infection. These antiviral medicines have replaced lamivudine as the first choice in the prevention of HBV recurrence after liver transplantation. Various therapies that are composed of entecavir, tenofovir, and lamivudine plus adefovir, with or without HBIG have been adopted in several liver transplant centers. This article reviews the recent advances in prophylaxis for the recurrence of hepatitis B after liver transplantation.

Entecavir has high efficacy and safety in white patients with chronic hepatitis B and comorbidities

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of entecavir monotherapy in nucleos(t)ide-naive chronic hepatitis B patients and to analyse the influence of the comorbidity burden on therapy outcome.

METHODS

We retrospectively analysed data from 237 nucleos(t)ide-naive chronic hepatitis B white patients treated with entecavir (0.5 mg/day) at 23 Spanish centres. For the efficacy and safety analyses, patients were grouped according to their baseline comorbidities.

RESULTS

The mean age of the cohort was 43 years (range: 19-82 years); 73% were male, 83% were white, and 33% were hepatitis B e antigen (HBeAg) positive. At baseline, the median hepatitis B virus DNA level was 6.20 log10 IU/ml. Of the patients, 18% had cirrhosis, 9.7% had diabetes, 16.3% had hypertension, and 15.7% had obesity; 13.4% of patients had more than one comorbid condition. Virological and biochemical responses at month 36 were obtained independently of the patients' baseline comorbid condition. Of 10 HBeAg-positive patients who discontinued treatment after HBeAg seroconversion, those who had not also cleared HBsAg (six) experienced virological recurrence in a median 5.6 months. There were no treatment discontinuations due to adverse events. Three patients were diagnosed with hepatocellular carcinoma at months 12, 30 and 54, and six experienced hepatic decompensation during follow-up. The median serum creatinine levels did not increase after 36 months of treatment, even in patients with comorbidities.

CONCLUSION

Entecavir is safe, well tolerated, and highly effective, even in patients with comorbid condition(s). Discontinuation of treatment in patients who have not been cleared of HBsAg may lead to virological recurrence.

The risk of hepatitis B virus reactivation and the role of antiviral prophylaxis in hepatitis B surface antigen negative/hepatitis B core antibody positive patients with diffuse large B-cell lymphoma receiving rituximab-based chemotherapy

The risk factors and the role of prophylactic antiviral therapy of hepatitis B virus (HBV) reactivation in patients with hepatitis B surface antigen (HBsAg) negative/hepatitis B core antibody (HBcAb) positive disease remain controversial. We reviewed 629 patients with diffuse large B-cell lymphoma (DLBCL). Among 629 patients, 150 of 246 patients with resolved HBV (HBsAg negative and HBcAb positive) were treated with rituximab-combined therapy. Among these 150 patients, none of 104 patients (0.0%) who were hepatitis B surface antibody (HBsAb) positive experienced HBV reactivation versus four of 46 patients (8.7%) who were HBsAb negative (p = 0.008). One of 113 patients (0.9%) with International Prognostic Index (IPI) 0-2 suffered HBV reactivation versus three of the remaining 37 patients (8.1%) with IPI 3-5 (p = 0.047). HBsAb and IPI are potential risk factors for HBV reactivation. The use of prophylactic agents may not be recommended for these patients until the occurrence of HBV reactivation.

Comparison of the efficacy of Lamivudine plus adefovir versus entecavir in the treatment of Lamivudine-resistant chronic hepatitis B: a systematic review and meta-analysis

BACKGROUND

Hepatitis B virus infection remains 1 of the major health threats worldwide. Currently, lamivudine plus adefovir combination therapy or entecavir monotherapy is usually used for the treatment of patients with lamivudine-resistant chronic hepatitis B (CHB). However, there are few systematic comparisons between the efficacy of lamivudine plus adefovir and the efficacy of entecavir in the treatment of these patients.

OBJECTIVE

The goal of this systematic study and meta-analysis was to assess the efficacy of lamivudine plus adefovir compared with entecavir for the treatment of patients with lamivudine-resistant CHB.

METHODS

A comprehensive literature search of PUBMED, Web of Science, WANFANG database, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Review, were screened to obtain citations from January 1990 to January 2012 in this study. Data analysis was done by using the Review Manager Software 5.1.

RESULTS

Eight studies were suitable for analysis. A total of 696 patients with lamivudine-resistant CHB were studied and grouped according to treatment: 341 patients in the entecavir group and 355 patients in the lamivudine plus adefovir group. The results found that the rates of undetectable hepatitis B virus DNA levels, alanine aminotransferase normalization, hepatitis B e antigen loss, and hepatitis B e antigen seroconversion were not significantly different between the lamivudine plus adefovir group and the entecavir group. Moreover, the rate of adverse reactions was also not significantly different between the 2 groups. However, virologic breakthrough for the patients with lamivudine resistance was higher in the entecavir group than in the lamivudine plus adefovir group.

CONCLUSIONS

For these CHB patients with lamivudine resistance, lamivudine plus adefovir was a better treatment option than entecavir alone.

Laboratory evaluation of three regimens of treatment of chronic hepatitis B: tenofovir, entecavir and combination of lamivudine and adefovir

BACKGROUND

Chronic hepatitis B is a disease of concern due to its life-threatening complications like cirrhosis, and hepatocellular carcinoma (HCC) in 20-40% of patients. There are about 400 million people affected worldwide with HBV, and over 300,000 die every year from HBV-related diseases. Oral antivirals like lamivudine, adefovir, entecavir, and tenofovir are commonly used to treat chronic hepatitis B. In this study, we tried to evaluate the comparative efficacy of these drugs alone and in combination.

MATERIALS AND METHODS

Chronic hepatitis B patients with HBV-DNA more than 10⁴Copies/mL irrespective of their HBeAg status (n=60) were enrolled in a prospective study. 21, 20, and 19 patients were treated with lamivudine (100 mg/day) plus adefovir (10 mg/day) combination entecavir monotherapy (0.5 mg/day) and tenofovir monotherapy (300 mg/day), respectively and were followed up for 24 weeks with their virological, serological, and biochemical markers measured at 12 and 24 weeks.

RESULTS

After 24 weeks of treatment, there was no significant difference between the 3 groups in suppressing HBV-DNA to undetectable levels. The median decrease in HBV-DNA levels from baseline was better with tenofovir and entecavir monotherapies than lamivudine and adefovir combination, which was statistically significant. There was no significant difference between the 3 groups in HBsAg and HBeAg seroconversion and normalization of biochemical parameters.

CONCLUSION

Entecavir and tenofovir monotherapy were found to be more effective than lamivudine plus adefovir combination in reducing the HBV-DNA levels. However, lamivudine plus adefovir combination was not too inferior, especially when cost of treatment was taken into consideration.

Impact of hepatitis B e antigen-suppressing mutations on the replication efficiency of entecavir-resistant hepatitis B virus strains

Hepatitis B e antigen (HBeAg)-negative hepatitis B commonly requires long-term treatment with nucleos(t)ide analogues aiming at persistently suppressing hepatitis B virus (HBV) replication to halt progression of liver disease and prevent complications. Entecavir (ETV) is widely used in HBeAg-negative hepatitis B, but distinct HBV polymerase mutations can confer resistance against ETV, in conjunction with lamivudine resistance. Precore (PC) and basal core promoter (BCP) mutations that underlie HBeAg-negativity enhance replication of lamivudine-resistant mutants. To comprehensively analyse the impact of PC or BCP mutations on viral replication of ETV-resistant HBV mutants, replication-competent HBV constructs were generated harbouring lamivudine resistance (rtM204V/rtL180M, rtM204I) plus ETV resistance (rtS202G, rtS202I or rtT184G) on wild-type (WT)-, PC- and BCP-backgrounds. Functional consequences on viral fitness and susceptibility to antivirals were assessed in vitro. The presence of any ETV resistance drastically reduced viral replication when compared to WT HBV. In rtS202G mutants (plus lamivudine resistance), addition of either PC or BCP mutations moderately enhanced the reduced replication, without reaching WT HBV levels. In rtS202I or rtT184G mutants, PC and BCP mutations did not significantly improve viral fitness. All ETV-resistant constructs, independently of PC or BCP mutations, showed resistance towards ETV and lamivudine, but remained susceptible to tenofovir. Our data demonstrate that HBeAg-suppressing PC or BCP mutations cannot restore the strongly reduced replicative capacity of ETV-resistant HBV mutants to WT level, although they moderately increase replication of rtS202G combination mutants. ETV resistance thereby differs from lamivudine resistance alone, corroborating that ETV is in short term a safe option for HBeAg-negative patients.

Risk of hepatitis B virus (HBV) reactivation in hepatitis B surface antigen negative/hepatitis B core antibody positive patients receiving rituximab-containing combination chemotherapy without routine antiviral prophylaxis

The use of rituximab has been associated with increased risk of hepatitis B virus (HBV) reactivation in patients who are hepatitis B surface antigen (HBsAg) negative and antihepatitis B core antibody (anti-HBc) positive. We aim to determine the rate of HBV reactivation in this group of patients who received rituximab-containing combination chemotherapy without concomitant antiviral prophylaxis and to identify potential risk factors for reactivation. Sixty-two HBsAg negative/anti-HBc positive patients with B-cell lymphoma treated with rituximab-based immunochemotherapy from 2006 to 2009 were included. None of the patients received concomitant antiviral prophylaxis. In this cohort, 48 (77%) patients received rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), eight (13%) received rituximab with cyclophosphamide, vincristine and prednisolone, and six (10%) received other chemotherapy regimens. Two patients suffered HBV reactivation; both were above 70 years of age, received R-CHOP chemotherapy and were negative for antihepatitis B surface antibody (anti-HBs) at baseline. One of the two patients reactivated shortly after completion of R-CHOP chemotherapy while the other reactivated during rituximab maintenance treatment. Thus, the overall reactivation rate in this cohort of patients is 3% (2/62), 4% (2/48), and 25% (1/4) in patients who received R-CHOP chemotherapy and who received rituximab maintenance, respectively. The rate of HBV reactivation is low in patients who are HBsAg negative/anti-HBc positive receiving rituximab-based combination chemotherapy without concomitant antiviral prophylaxis. However, elderly patients, particularly those without anti-HBs, seemed particularly at risk.

De novo combination of lamivudine and adefovir versus entecavir monotherapy for the treatment of naïve HBeAg-negative chronic hepatitis B patients

PURPOSE

Either combination treatment or monotherapy using agents with a high genetic barrier are recommended for hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). The aim of this study was to compare effect of naïve HBeAg-negative CHB patients with either de novo combination of lamivudine (LAM) and adefovir dipivoxil (ADV) or entecavir (ETV) monotherapy.

METHODS

HBeAg-negative CHB patients (n = 71) with ALT levels between 2 and 10 times the upper normal limit and HBV DNA levels >10(4) copies/mL were enrolled. Patients were treated with either LAM 100 mg plus ADV 10 mg per day (n = 31) or ETV 0.5 mg per day (n = 40) for 48 weeks.

RESULTS

The average reduction in HBV DNA level compared with baseline were 5.16 ± 1.69 log in the LAM + ADV group and 5.36 ± 1.70 log in the ETV group by week 48 (P = 0.624). The virological response (VR) rates were 80.65 and 77.5%, the biochemical response (BR) rates were 93.55 and 90.00% at week 48 in the LAM + ADV and ETV groups, respectively. There was no significant difference in the VR and BR between the two groups. During the 48-week treatment period, virological breakthrough and serious side effects were not noted in any patient.

CONCLUSIONS

Both LAM + ADV combination therapy and ETV monotherapy are effective in naïve HBeAg-negative CHB patients, but further studies are needed to obtain long-term results.

How I treat and monitor viral hepatitis B infection in patients receiving intensive immunosuppressive therapies or undergoing hematopoietic stem cell transplantation

Hepatitis B virus (HBV) reactivation is a serious but preventable complication of immunosuppression. Full HBV serologic profile must be obtained from all patients receiving intensive immunosuppressive therapy. In general, preemptive anti-HBV therapy is more effective than giving treatment after development of reactivation. Prompt lamivudine therapy should be given to at-risk patients who are hepatitis B surface antigen (HBsAg)-positive. It is recommended that lamivudine be continued until at least 6 months after the cessation of immunosuppression. Some patients requiring a longer duration of lamivudine therapy are at risk of developing drug resistance. The newer anti-HBV agents are effective in overcoming lamivudine resistance. Early use of these agents may be considered. HBV reactivation was observed in HBsAg-negative patients with occult HBV infection (HBV DNA-positive) who are on heavy immunosuppression. The optimal management of this group of patients is unclear. For patients receiving allogeneic HSC transplants, the HBV status of the donors requires special attention. To minimize the risk of transmission of infection to recipients, HBsAg-positive donors should receive adequate anti-HBV therapy before HSC donation. As the result of adoptive immune transfer, clearance of HBsAg is observed in HBsAg-positive patients receiving HSC transplants from donors who are positive for hepatitis B surface and core antibodies.