Differences in nephrotoxicity risk and renal effects among anti-viral therapies against hepatitis B

Renal dysfunction during treatment of chronic hepatitis B with tenofovir disoproxyl fumarate and associated risk factors

OBJECTIVES

To analyze the evolution of glomerular filtration rate (GFR) and the presence of renal tubular dysfunction during the treatment of chronic hepatitis B virus (HBV) infection with tenofovir disoproxil fumarate (TDF) and to determine the risk factors involved.

METHODS

Retrospective cohort observational study of adults with chronic hepatitis B. Exclusion: hepatitis C virus-HBV coinfection, diabetes, baseline GFR less than 60 ml/min. Measurements of serum and urinary creatinine and phosphate; urinary albumin, retinol-binding protein (RBP) and neutrophil gelatinase-associated lipocalin (NGAL) were performed. Univariate and multivariate analyses tracked factors associated with worsening GFR.

RESULTS

A total of 120 individuals were included: 35% NAÏVE (G1); 49.2% HBV using TDF (G2); 15.8% HBV-HIV using TDF (G3); 63.3% men; 60.8% white; 30% hypertensive. Average age was 50.5 years (SD ± 12.9 years). Reactive HBeAg predominated in G3 ( P  < 0.001) and cirrhosis in G2 ( P  < 0.036). NGAL was elevated in 5.3% of cases (G1 = 3.2%; G2 = 8.7%; G3 = 0%; P  = 0.582), RBP in 6.7% (G1, G3 = 0%; G2 = 13.6%; P  = 0.012), urinary phosphate/creatinine ratio in 16.2% (G1 = 15.2%; G2 = 14.5%; G3 = 23.5%; P  = 0.842) and urinary albumin/creatinine ratio in 12.9% (G1 = 12.2%; G2 = 10.7%; G3 = 21.1%; P  = 0.494). Worsening of renal function occurred in 22.5% of the population (G1 = 11.9%; G2 = 28.8%; G3 = 26.3%; P  = 0.122), independently associated only with systemic arterial hypertension [adjusted odds ratio (AOR) = 4.14; P  = 0.008], but not to TDF (AOR = 2.66; P  = 0.110) or male sex (AOR = 2.39; P  = 0.135). However, the concomitance of these variables generated a high estimated risk for this outcome (51%).

CONCLUSIONS

Renal tubular dysfunction was uncommon according to NGAL, RBP or urinary phosphate/creatinine ratio. TDF was not an independent factor for worsening renal function, significantly associated only with systemic arterial hypertension. However, in hypertensive men, the use of TDF should be monitored.

The Effects of the COVID-19 Pandemic on Clinical and Laboratory Follow-up of Patients Diagnosed With Chronic Hepatitis B: A Multicenter, Prospective, Observational Study

Background: Chronic hepatitis B (CHB) patients who are under the treatment of antiviral agents should be monitored in routine control visits. However, during the COVID-19 pandemic, the visits were interrupted. Objectives: This study aimed to investigate whether these patients were affected regarding clinical, laboratory, and treatment outcomes. Methods: This prospective study consisted of CHB patients aged > 18 who were applied to 3 tertiary centers between 14 February and 30 March 2022. The patients were selected from the ones who regularly applied to outpatient clinics and under the treatment of antiviral agents before the pandemic. The demographic and laboratory values, including serologic, biochemistry, and molecular results, were compared between the 2 groups who came and did not come to control visits. Results: A total number of 220 patients were included. More than half (n = 142, 64.5%) were female. The median age was 44 years (19 - 73). A hundred and forty-two (64.5%) patients did not come to control visits during the pandemic. The most common reason was anxiety about COVID-19. The tenofovir treatment was replaced with entecavir (ETV) due to osteopenia and with alafenamide due to osteopenia and/or renal failure. The previous agents were re-started in 27 (79.5%) patients who discontinued the treatment. Conclusions: The COVID-19 pandemic negatively impacted the follow-up of CHB patients. In this regard, 15.5% of patients stopped their treatments. The patients who stopped their follow-ups and continued tenofovir disoproxil fumarate (TDF) had proteinuria and decreases in bone mineral density (BMD) and estimated glomerular filtration rate (eGFR) levels.

Efficacy and Renal Safety of Prophylactic Tenofovir Alafenamide for HBV-Infected Cancer Patients Undergoing Chemotherapy

There are no data comparing the efficacy and safety of prophylactic entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) for HBV-infected cancer patients undergoing chemotherapy. This study aimed to compare the efficacy and renal safety of ETV, TDF and TAF in this setting. HBsAg-positive cancer patients treated with ETV (n = 582), TDF (n = 200) and TAF (n = 188) during chemotherapy were retrospectively enrolled. Antiviral efficacy and risk of renal events were evaluated. The rate of complete viral suppression at 1 year was 94.7%, 94.7% and 96.1% in ETV, TDF and TAF groups, respectively (p = 0.877). A significant proportion of patients developed renal dysfunction during chemotherapy. The incidences of acute kidney injury (AKI) and chronic kidney disease stage migration were comparable among the ETV, TDF and TAF groups. TAF was relatively safe in patients with predisposing factors of AKI, including hypoalbuminemia and cisplatin use. In patients who were switched from TDF to TAF during chemotherapy, the renal function remained stable and viral suppression was well maintained after switching. In conclusion, TAF had good renal safety and comparable efficacy with ETV and TDF for HBV-infected cancer patients receiving chemotherapy. Switching from TDF to TAF during chemotherapy is safe, without a loss of efficacy.

Comparison of renal safety and bone mineral density of tenofovir and entecavir in patients with chronic hepatitis B: A Systematic Review and Meta-analysis

OBJECTIVE

Tenofovir disoproxil fumarate (TDF) and entecavir (ETV) are recommended as first-line treatments for chronic hepatitis B (CHB). However, the safety of these two drugs remains controversial. This study aims to evaluate and compare renal function and bone mineral density in CHB patients who took TDF or ETV.

METHODS

The electronic databases of the Cochrane Library, PubMed, and Embase were searched. The key words were: "CHB," "tenofovir," and "entecavir". Heterogeneity and subgroups were analyzed.

RESULTS

16 studies met the inclusion criteria. There was no significant difference in serum creatinine levels between the TDF and the ETV group. There was a significant standardized mean difference in serum estimated glomerular filtration rate (eGFR) between months (12 months: SMD [95%CI] = -0.07 [-0.12, -0.01]; 18-24 months: SMD [95%CI]=-0.11[-0.17],-0.05]), but no significant difference emerged in the long-term drug use for over 24 months. There was no significant difference in the incidence of osteopenia/osteoporosis (I²=41%, RR [95%CI]=1.29[0.93,1.77], p=0.13>0.05).

CONCLUSIONS

Compared with the ETV group, a greater reduction in eGFR and serum phosphorus levels was observed in the TDF group. There was no significant difference in the incidence of osteopenia/osteoporosis between the two groups.

Use of Hepatitis B Viremic donors in kidney transplant recipients: A single center experience

BACKGROUND

Utilization of Hepatitis B virus (HBV)-infected kidney allografts represents an opportunity to bridge the gap between organ supply and demand. Highly efficacious vaccines and anti-viral therapies allow these allografts to be transplanted with negligible risk to the recipient.

OBJECTIVE

The purpose of this study was to describe the prophylactic strategies and related clinical outcomes of kidney transplant recipients who received a kidney from an HBV viremic donor.

RESULTS

Eight patients received an allograft from an HBV viremic deceased kidney donor between January 1, 2017 and December 4, 2020. All recipients were immune to hepatitis B with a surface antibody titer greater than or equal to 10 mIU/mL (range: 12 - >1000 mIU/mL). After transplant, 62.5% demonstrated HBV core antibody seroconversion at an average of 47.4 ± 28.5 days post-transplant. Anti-viral prophylaxis was initiated in 87.5% of patients; 62.5% preemptively during the transplant admission (range 1-3 days post-transplant) and 25% following HBcAb seroconversion (range 45-304 days post-transplant). Of the four patients who were started on entecavir preemptively, two subsequently core converted. These two patients had an HBV surface antibody less than 100 mIU/mL at the time of transplant. None of the recipients converted to HBV surface antigen positivity. The average estimated glomerular filtration rate was 41 ± 19 mL/min/1.73m² , and there were no significant elevations in liver enzymes through one year post-transplant.

CONCLUSION

The use of HBV viremic kidney allografts may represent an additional source of transplant organs; however, more studies are needed to better elucidate the optimal protective strategies for these recipients. This article is protected by copyright. All rights reserved.

Long-term renal safety between patients with chronic hepatitis B receiving tenofovir vs. entecavir therapy: A multicenter study

Renal safety is a critical issue in chronic hepatitis B (CHB) patients receiving long-term entecavir (ETV) or tenofovir disofuroxil fumarate (TDF) therapy. We investigated their effects on estimated glomerular filtration rate (eGFR). Treatment-naive CHB patients receiving ETV or TDF for ≥1 year were recruited. The eGFR was assessed using the Chronic Kidney Disease Epidemiology Collaboration equation. We calculated average annual percent change (AAPC) in eGFR using Joinpoint regression. At the beginning of the observation, the ETV group had more unfavorable conditions than the TDF group: lower eGFR and higher FIB-4 and APRI than the TDF group (all p < .001). After 6 years of antiviral therapy, the mean eGFR in the ETV group (n = 1793) was maintained (96.0 at first year to 95.6 ml/min/1.73 m² at sixth year; AAPC -0.09%; p = .322), whereas that in the TDF group (n = 1240) significantly decreased annually (101.9 at first year to 96.9 ml/min/1.73 m² at sixth year; AAPC -0.88%; p < .001). Notably, in the TDF group, even patients without diabetes (AAPC -0.80%; p = 0.001) or hypertension (AAPC -0.87%; p = .001) experienced significant decrease in eGFR. Expectably, accompanying diabetes (AAPC -1.59%; p = .011) or hypertension (AAPC -1.00%; p = .002) tended to accelerate eGFR decrease. TDF treatment (odds ratio 1.66, p < .001), along with eGFR<60 ml/min/1.73 m² , serum albumin<3.5 mg/dl, and hypertension, were independently associated with ongoing renal dysfunction, defined as a negative slope of the mean eGFR change. In conclusion, compared with ETV, long-term TDF treatment induced slow, but progressive renal dysfunction. Although the annual eGFR change by TDF was small, careful monitoring is necessary, especially in patients requiring life-long therapy.

Is urinary β2-microglobulin a reliable marker for assessment of renal tubular dysfunction in chronic hepatitis B patients receiving tenofovir therapy?

BACKGROUND AND AIM

Urinary β2-microglobulin (β2-M) is a marker for renal tubular dysfunction. The current study aimed to assess urinary β2-M as a reliable marker for early prediction of tenofovir disoproxil fumarate (TDF)-related nephrotoxicity among hepatitis B virus (HBV) patients.

METHODS

Forty-two HBV patients who were a candidate for TDF therapy or have recently started it (for less than 6 months) were enrolled and subjected to demographic, clinical, laboratory assessment, abdominal ultrasound and transient elastography. The glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault equation. Also, urinary β2-M was measured by the ELISA method within 6 months after the introduction of TDF treatment and 6 months later.

RESULTS

Mean age was 41.8 (9.55) years, 27 were males and 59.5% of patients have elevated urinary β2-M after 6 months follow-up of TDF therapy. Urinary β2-M was 0.07 ± 0.07 μg/ml at baseline and insignificantly increased up to 0.09 ± 0.08 μg/ml after 6 months follow-up. Despite the insignificant increase in serum creatinine from 0.85 ± 0.23 mg/dl at baseline to 0.9 ± 0.21 mg/dl after 6 months and the insignificant decrease in eGFR from 126.2 ± 39.72 ml/min at baseline and 117.64 ± 42.23 ml/min at 6 months follow-up. No correlation was found between the changes in urinary β2-M and the changes in other renal function indices at baseline and 6 months follow-up.

CONCLUSIONS

Short-term TDF therapy is associated with nonsignificant changes either in eGFR or urinary β2-M; these changes are not clinically relevant that indicates disease progression. Therefore, the suitability of urinary β2-M as a screening tool for tenofovir induced tubular dysfunction should be further.

A novel evidence of serial changes of bone mineral density in chronic hepatitis B patients treated with entecavir

BACKGROUND AND AIMS

Tenofovir disoproxil fumarate (TDF) and Entecavir (ETV) are commonly used for patients with chronic hepatitis B (CHB), and renal or bone toxicity are possible concerns. This study is to evaluate the renal and bone effect of TDF compared with ETV in CHB patients.

METHODS

This is a retrospective study at Kaohsiung Chung-Gung memorial hospital, Taiwan, from June 2013 to December 2018. Patients with CHB were prescribed with TDF or ETV for 3 years or above. Renal function was assessed at 12-week intervals. Dual-energy X-ray absorptiometry scans of the spine and femurs were performed at 48-week intervals. The propensity score analysis was conducted to balance the baseline characteristics of patients in both treatment groups.

RESULTS

A total of 258 patients were included in this study: TDF (n = 135) and ETV (n = 123). The prevalence of osteopenia was much higher in the TDF group at week 48 and week 96. The TDF group showed significant mean percentage decrease from baseline in bone mineral density throughout the treatment course. Logistic regression analysis adjusted for the propensity score demonstrated that the use of TDF was the only predictive factor of significant bone density loss at week 144. The mean percentage decline of estimated glomerular filtration rate was significant in the TDF group at all time points. Renal threshold phosphate concentration was similar among both treatment groups.

CONCLUSIONS

This study suggested CHB patients treated with TDF may experience increased risks of bone loss and renal deficits compared to those treated with ETV.

Long-term Nucleotide Analogue Treatment Has Higher Levels of Renal Toxicities than Does Entecavir in Patients with Chronic Hepatitis B

Background/Aims

Renal toxicity is a concern in patients with chronic hepatitis B taking nucleotide analogues, such as adefovir (ADV) and tenofovir disoproxil fumarate (TDF). We sought to determine the long-term renal effects of nucleotide analogue treatment versus entecavir (ETV) treatment.

Methods

In this retrospective single-center study, we selected 87 patients who were treated with ADV and subsequently with TDF from June 2008 to December 2013. ETV-treated patients were matched by treatment duration. We analyzed the creatinine increase over 0.5 mg/dL, glomerular filtration rate (GFR) decrease over 25%, phosphorus decrease under 2.0 mg/dL, and dose reduction of antiviral agents.

Results

The median follow-up period was 60.0 months for both groups. The incidence of liver cirrhosis was higher in the ADV-TDF group than in the ETV group (32.2% vs 74.7%, p<0.01). Creatinine increased in both groups during follow-up, but the difference was not significant (5.7% and 2.3%, p=0.44). In addition, GFR decreased more often in the ADV-TDF group than in the ETV group (31.0% and 14.9%, p=0.01). After multivariate Cox regression analysis, ADV-TDF treatment was significantly associated with a GFR decrease over 25% (hazard ratio, 2.10; 95% confidence interval, 1.08 to 4.10; p=0.03) after adjusting for the baseline GFR decrease.

Conclusions

Patients taking nucleotide analogues had a significantly higher number of renal events than did those taking ETV. Clinicians should be aware of the development of renal toxicity in this patient population. Further long-term studies are warranted.

Telbivudine for renal transplant recipients with chronic hepatitis B infection: a randomized controlled trial with early termination

BACKGROUND

The aim of this study was to analyze changes in renal function in HBsAg-positive renal transplant recipients receiving lamivudine who did or did not switch to telbivudine.

METHODS

In this prospective randomized clinical trial (RCT), HBsAg-positive renal transplant recipients who had received lamivudine prophylaxis for at least 6 months were 1:2 randomized to receive either lamivudine or telbivudine for another 24 months. Renal function was evaluated by creatinine level and estimated glomerular filtration rate (eGFR) at the time of randomization (baseline), 6, 12, 18, and 24 months respectively.

RESULTS

This RCT was prematurely terminated after recruiting only 17 patients due to a high incidence (61.5%; 8/13) of clinical myalgia in the telbivudine group. Cox's proportional hazards model revealed that there was no independent predictor of myalgia. Based on intention-to-treat and per protocol analyses using generalized estimating equations, the patients in the randomized telbivudine group had a significantly increased eGFR and the patients in the lamivudine group had a significantly decreased eGFR at the end of follow-up compared to the values at study enrollment. However, there was no significant difference between the lamivudine and telbivudine groups.

CONCLUSIONS

The renal protective effect of telbivudine for HBsAg positive renal transplant recipients was uncertain for high incidence of myalgia and only patients who were on telbivudine for 24 months had renal function maintenance.

Comparison of renal safety of tenofovir and entecavir in patients with chronic hepatitis B: Systematic review with meta-analysis

BACKGROUND

Recently, the American Association for the Study of Liver Disease suggested no preference between tenofovir (TDF) and entecavir (ETV) regarding potential long-term risks of renal complications. Over the years, renal safety has become a critical concern in nucleos(t)ide analog-treated patients due to the long-term use of these drugs. However, existing studies do not show significant differences in renal dysfunction between these two drugs. Further, there is a paucity of studies comparing the long-term renal effects of TDF and ETV.

AIM

To investigate the effects of TDF and ETV on renal function, we performed systematic review and meta-analysis.

METHODS

Two investigators independently searched the Cochrane Library, MEDLINE, and Embase databases for randomized controlled trials and nonrandomized studies (NRSs) using the keywords “CHB”, “Tenofovir”, and “Entecavir”, and additional references were obtained from the bibliographies of relevant articles published through December 2017. The quality of each study was assessed using the Newcastle-Ottawa scale and the Grading of Recommendations Assessment, Development and Evaluation criteria. The primary outcome was the change in serum creatinine level in the TDF and ETV groups at baseline, 6 mo, 12 mo and 24 mo.

RESULTS

Nine NRSs comprising 2263 participants met the inclusion criteria. Changes in creatinine levels were higher in the TDF group than in the ETV group at 6 mo [mean difference (MD) = 0.03 mg/dL; 95%CI: 0.02-0.04; I² = 0%], 12 mo (MD = 0.05 mg/dL; 95%CI: 0.02-0.08; I² = 78%), and 24 mo (MD = 0.07 mg/dL; 95%CI: 0.01-0.13; I² = 93%). The change in estimated glomerular filtration rate (eGFR) was significantly higher in the TDF group than in the ETV group at 6 mo [standardized mean difference (SMD), -0.22; 95%Cl: -0.36--0.08; I² = 0%], 12 mo (SMD = -0.24; 95%Cl: -0.43--0.05; I² = 50%), and 24 mo (-0.35; 95%Cl: -0.61- -0.09; I² = 67%).

CONCLUSION

TDF statistically significantly increased serum creatinine levels and decreased the eGFR in 6-24 mo compared to ETV, with moderate to low quality of evidence. However, the differences are negligible.

Value of Cystatin C-Based e-GFR Measurements to Predict Long-Term Tenofovir Nephrotoxicity in Patients With Hepatitis B

BACKGROUND

Cystatin C is a genuine marker for detecting minor reductions in estimated glomerular filtration rate (e-GFR).

STUDY QUESTION

We aimed to investigate the efficiency of cystatin C levels in predicting nephrotoxicity due to antiviral therapy in patients with chronic hepatitis B virus infection.

STUDY DESIGN

Seventy-six naive hepatitis B virus patients and 44 controls were enrolled in this prospective cohort study.

MEASURES AND OUTCOMES

Serum cystatin C, phosphate and creatinine levels, and urinary albumin/creatinine ratios of all patients were measured at baseline, 3rd, 12th, and 24th months. Nephrotoxicity was determined according to the amount of change in creatinine level at the fourth year of treatment compared with baseline ([INCREMENT]Cr0-4).

RESULTS

Mean age was 36.1 ± 9.2 years and 40 (52.2%) of patients were women. There was no significant difference between baseline values of tenofovir disoproxil fumarate and entecavir groups. Although the creatinine level at the fourth year of treatment was statistically nonsignificant compared with baseline in the entecavir group, it was significantly higher in the fourth year of tenofovir treatment compared with baseline (0.95 ± 0.27 mg/dL vs. 0.76 ± 0.16 mg/dL, P = 0.002). While the increase in [INCREMENT]Cr0-4 was ≥0.2 mg/dL in 43.2% of patients in the tenofovir group, this rate was 18.8% in the entecavir group. Diagnostic accuracy in identifying decreased renal function as area under the curve (AUC) was high for baseline serum cystatin C level; furthermore, the highest AUC was calculated for cystatin C plus creatinine-based e-GFR equation (AUC: 0.81, P < 0.001).

CONCLUSIONS

Long-term tenofovir disoproxil fumarate nephrotoxicity can be predicted by serum cystatin C plus creatinine-based e-GFR measured before treatment.

Changes in Renal Function in Patients With Chronic HBV Infection Treated With Tenofovir Disoproxil Fumarate vs Entecavir

BACKGROUND & AIMS

It is unclear whether drugs used to treat chronic hepatitis B virus (HBV) infection cause significant renal impairment. We compare adjusted mean estimated glomerular filtration rates (eGFR; mL/min/1.73 m²) of patients with chronic HBV infection treated with tenofovir disoproxil fumarate (TDF) vs patients treated with entecavir.

METHODS

We performed a retrospective study of patients with chronic HBV infections treated with TDF (n = 239) or entecavir (n = 171), from 2000 through 2016, followed for a mean time of 43-46 months. Levels of serum creatinine were measured ≥12 months while patients received treatment. Patients did not have prior exposure to adefovir or HCV, HDV, or HIV co-infection. We performed propensity score matching (PSM) for age, sex, presence of hypertension, diabetes mellitus, baseline eGFR, cirrhosis, and follow-up duration. We performed multivariate generalized linear modeling, adjusting for cirrhosis, diabetes, and hypertension, to estimate adjusted mean eGFR for matched and unmatched cohorts. Cox regression was used to identify predictors of renal impairment.

RESULTS

eGFRs were ≥60, after PSM, in 116 patients given entecavir and in 116 patients given TDF; eGFRs were <60 in 32 patients given entecavir and 26 patients given TDF. Multivariate generalized linear modeling of the unmatched overall and <60 eGFR cohorts revealed significantly lower adjusted mean eGFRs in patients given TDF (all P < .001). However, in the eGFR ≥60 PSM cohort, the adjusted mean eGFR was similar between patients receiving either treatment. In Cox regression analysis, TDF was not associated with mild or moderate renal impairment compared with entecavir.

CONCLUSION

In a retrospective study of patients with chronic HBV infections treated with TDF vs entecavir, we found that TDF was not associated with higher risk of worsening renal function during short- or intermediate-term follow-up periods, among patients without significant renal impairment. Additional studies, with longer follow-up periods, are needed because treatment for chronic HBV infection is generally long term or life-long. For patients with baseline renal impairment, significant renal decline was among patients given TDF compared to patients given entecavir.

Hepatitis B and renal function: A matched study comparing non-hepatitis B, untreated, treated and cirrhotic hepatitis patients

BACKGROUND & AIM

Renal impairment is associated with chronic hepatitis B (CHB). To overcome prior study design differences, we used propensity score matching to balance the non-CHB and CHB cohorts and generalized linear modelling (GLM, models using probit and logit linking functions for complex models) to evaluate the effect of CHB, treatment and cirrhosis on renal function.

METHODS

A retrospective cohort (1996-2017) from one U.S. university medical centre. Included patients had ≥12 months of serial creatinine laboratories and a baseline estimated glomerular filtration rate (eGFR, by the Modification of Diet in Renal Disease Study equation) ≥60 mL/min/1.73 m² . Propensity score matching was performed using age, sex, ethnicity, diabetes, hypertension and baseline eGFR. GLM was performed to generate adjusted mean eGFR over time.

RESULTS

Adjusted mean eGFR was significantly higher for non-CHB vs. untreated CHB patients (eGFR 87.4 vs. 85.6, P= 0.004, n = 580, median follow-up = 82 months). A significant difference in adjusted mean eGFR between untreated vs. entecavir (ETV)-treated CHB patients (eGFR 85.1 vs. 83.5, P= 0.02, n = 340, median follow-up = 70 months) was found among non-cirrhotic CHB. Among treated CHB, there was no difference in adjusted mean eGFR between non-cirrhotic vs. cirrhotic patients (eGFR 77.0 vs. 76.5; P= 0.66, n = 112, median follow-up = 58 months).

CONCLUSION

After PSM and GLM, the significant predictors for worsening renal function were age, hypertension and diabetes mellitus but not CHB, ETV or cirrhosis. However, given small sample size, data regarding the use of ETV in patients with cirrhosis should be interpreted with caution and requires additional investigation.

Effectiveness and safety of switching to entecavir hepatitis B patients developing kidney dysfunction during tenofovir

BACKGROUND AND AIMS

Tenofovir disoproxil fumarate (TDF) is recommended for chronic hepatitis B (CHB) treatment, but it may induce kidney dysfunction whose management is not yet known. This Italian, multicentre, retrospective study aimed to assess the efficacy and safety of switching to entecavir (ETV) patients who developed TDF-associated glomerular and/or tubular dysfunction.

METHODS

A total of 103 TDF-treated patients were included as follows: age 64 years, 83% male, 49% cirrhotics, 98% with undetectable HBV DNA, 47% with previous lamivudine resistance (LMV-R) and 71% previously treated with adefovir. Twenty-nine (28%) were switched to ETV because estimated glomerular filtration rate (eGFR_MDRD ) was <60 mL/min, 37 (36%) because blood phosphate (P) levels were <2.5 mg/dL and 37 (36%) for both reasons. Kidney, liver and virological parameters were recorded every 4 months thereafter.

RESULTS

During 46 (4-115) months of ETV treatment, all patients' renal parameters significantly improved as follows: creatinine from 1.30 to 1.10 mg/dL (P < 0.0001), eGFR_MDRD from 54 to 65 mL/min (P = 0.002), P from 2.2 to 2.6 mg/dL (P < 0.0001) and maximal tubule phosphate reabsorption (TmPO4/eGFR) from 0.47 to 0.62 mmol/L (P < 0.0001). Thirteen patients (52%) improved their eGFR_MDRD class, P levels were normalised in 13 (35%), and eight (22%) showed improvements in both parameters. Viral suppression was maintained in all but five patients (5%), all of whom had been LMV-R. The 5-year cumulative probability of ETV-R was 0% in LMV-naïve patients, and 11% in LMV-R patients (P = 0.018).

CONCLUSIONS

Entecavir is an effective and safe rescue strategy for CHB patients who develop renal dysfunction during long-term TDF treatment.

Longitudinal trends in renal function in chronic hepatitis B patients receiving oral antiviral treatment

BACKGROUND

Long term renal safety of antiviral agents against hepatitis B virus (HBV) has been debated.

AIM

To compare longitudinal trends of renal function among HBV mono-infected patients receiving entecavir (ETV), tenofovir disoproxil fumarate (TDF), and adefovir (ADV) in comparison to untreated subjects.

METHODS

A retrospective cohort consisting of 815 patients with chronic HBV infection was constructed. Serial estimated glomerular filtration rate (eGFR) was compared to the expected rate of age-dependent decline in eGFR, derived from the National Health and Nutrition Examination Survey (NHANES) data. Generalised estimating equations and linear mixed-effects models were used to compare trends in eGFR (in mL/min/1.73m² as a "unit").

RESULTS

In NHANES data (n = 23 051), each year of age was associated with a 0.86 unit decrease in eGFR in subjects without hypertension and 0.96 units with hypertension. The Stanford cohort consisted of patients who received ETV (n = 207), TDF (n = 191), ADV (n = 46) or no therapy (n = 371). After a median follow-up 4.0 (interquartile range: 1.9-6.5) years, there was no significant difference in the expected and observed rates of eGFR decline in untreated HBV patients. Patients receiving antiviral treatment experienced steeper reduction in renal function than expected. In the multivariable model, ETV was associated with eGFR loss at 1.81 units per year (P = 0.06, compared to untreated patients). TDF- and ADV-treated patients experienced significantly higher rate of eGFR loss at 2.21 and 2.63 units per year, respectively (both P < 0.01).

CONCLUSION

In this longitudinal cohort study, HBV patients receiving antiviral therapy, particularly TDF and ADV, experienced more rapid loss in eGFR.

Risk of renal events during tenofovir disoproxil fumarate and entecavir antiviral prophylaxis in HBsAg-positive cancer patients undergoing chemotherapy

The risk of renal events in HBsAg-positive cancer patients receiving tenofovir disoproxil fumarate (TDF) or entecavir (ETV) antiviral prophylaxis during chemotherapy has not been evaluated. This study aimed to evaluate the renal safety of TDF and ETV during chemotherapy. Consecutive, 219 HBsAg-positive cancer patients treated with TDF (n = 106) or ETV (n = 113) for antiviral prophylaxis during chemotherapy with baseline serum creatinine (SCr) <1.2 mg/dL were retrospectively enrolled. Serial SCr levels and estimated glomerular filtration rate (eGFR) were monitored. The incidence of acute kidney injury (AKI) during antiviral prophylaxis was 33% and 38.9% in TDF and ETV groups, respectively (P = 0.441), while the incidence of sustained kidney injury was 11.3% and 11.5%, respectively (P = 1.000). By multivariate analysis, diuretics use (hazard ratio (HR) = 2.011, P = 0.042) and serum albumin levels (HR = 0.441, P = 0.001) were independent predictors of AKI; serum albumin levels (HR = 0.252, P = 0.002) was the only factor associated with sustained kidney injury; age (HR = 2.752, P < 0.001), baseline SCr levels (HR = 3.386, P < 0.001), and serum albumin levels (HR = 0.437, P = 0.001) were factors associated with a new eGFR <60 mL/min. 34.9% of patients in TDF group and 35.4% in ETV group had deteriorated chronic kidney disease (CKD) stage at the end of follow-up, respectively. There were no significant differences in the risk of renal events or CKD stage migration between TDF and ETV groups. Renal events may develop in about one-third of HBsAg-positive cancer patients undergoing chemotherapy. The risk of renal function impairment was comparable between patients treated with TDF and ETV antiviral prophylaxis.

Serum NGAL can act as an early renal safety biomarker during long-term nucleos(t)ide analogue antiviral therapy in chronic hepatitis B

Tubular renal toxicity is a side-effect of long-term therapy with nucleos(t)ide analogue(s) (NA) in chronic hepatitis B (CHB). There are no established surrogate markers in plasma of early NA-related toxicity. Neutrophil gelatinase-associated lipocalin (NGAL) is a protein produced by tubular cells following renal damage. We aimed therefore to retrospectively compare conventional renal markers (estimated glomerular filtration rates (eGFR) and urinary protein/creatinine ratio uPCR) with a sensitive biomarker (NGAL) in CHB patients on long-term NA therapy and assess the ability of new markers to predict NA-related renal toxicity (new onset of nonalbumin proteinuria). A total of 192 naïve CHB patients (median age 41 years, 78% males, 25% HBeAg+, 35% cirrhosis) were NA treated for at least 5 years (median 8.34 years, range 5.54-11.1 years). The eGFR and uPCR were compared at baseline and last clinical visit with serum NGAL concentrations measured by ELISA at same time-points and assessed according to the presence/absence of nonalbumin proteinuria at last visit. While baseline and last visit eGFR were similar (median:78 vs 84 mL/min), serum NGAL concentrations increased during therapy (median:9.4 vs 16.4 ng/mL, P < .05). The proportion of patients with proteinuria (uPCR > 15) increased between baseline and last visit (4.6% vs 21.4%, P < .05), with 30 (16%) patients having de novo nonalbumin proteinuria at last visit. High baseline NGAL concentrations were exclusive to patients with de novo nonalbumin proteinuria (median:31.7 vs 7.8 ng/mL, P < .01) and baseline NGAL levels >25 mg/mL were predictive of nonalbumin proteinuria at last visit (AUROC = 0.813). In conclusion, serum NGAL can act as a surrogate marker of early renal injury (de novo nonalbumin proteinuria) in CHB on long-term NA therapy.

Effect of tenofovir on renal function in patients with chronic hepatitis B

Tenofovir disoproxil fumarate (TDF) is widely used to treat patients with hepatitis B virus (HBV) infection. We investigated the effect of TDF on renal insufficiency in patients with chronic hepatitis B (CHB).A consecutive cohort analysis was applied to CHB patients taking prescribed TDF from January 2012 to May 2016 at Soonchunhyang University Seoul Hospital. Alterations over time in corrected calcium, phosphate, creatinine, and estimated glomerular filtration rate (eGFR) were analyzed using the generalized estimating equation method. The percentage increase in creatinine from baseline to the maximum creatinine level (delta creatinine) was compared according to the underlying disease using the Mann-Whitney U test. Cox proportional hazard regression model was used to determine risk factors associated with renal insufficiency.The baseline creatinine, eGFR, corrected calcium, and phosphate levels were 0.72 ± 0.01 mg/dL (mean ± SD), 106.37 ± 1.06 mL/min/1.73 m, 8.82 ± 0.04 mg/dL, and 3.42 ± 0.05 mg/dL, respectively. The creatinine level had increased significantly at 12, 24, 48, 72, and 96 weeks, while the eGFR level had decreased significantly at these 5 time points. Multivariate analysis confirmed that age ≥60 years and the baseline bilirubin level were independently associated with the risk of renal insufficiency. Delta creatinine was significantly higher in patients with diabetes mellitus (DM) than in patients without DM.Renal function was decreased from baseline in CHB patients receiving TDF therapy, which indicates that the renal function of patients undergoing treatment with TDF should be monitored regularly. Old age, DM, and serum bilirubin were risk factors for the development of renal insufficiency in CHB patients receiving TDF therapy.

Prevalence of chronic kidney disease in patients with chronic hepatitis B: A cross-sectional survey

Renal safety is a major concern during long-term antiviral treatment for chronic hepatitis B (CHB). This study aimed to investigate the prevalence of chronic kidney disease (CKD) in patients with CHB that had been treated with antiviral therapy. This was a single-centre, cross-sectional study in a real-life cohort in which all patients received antiviral treatment. Serum creatinine-based equations from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) were used to estimate the glomerular filtration rate (GFR). CKD was defined as an eGFR <60 mL/min/1.73 m² or a urinary albumin to creatinine ratio ≥ 3 mg/mmol (defined as albuminuria). Univariate and multivariate analyses were conducted to determine the risk factors of CKD. A total of 1985 patients were included in the analysis from February 2015 to December 2015. The mean age and median duration of antiviral treatment was 42.20 years and 17.05 months, respectively. The overall prevalence of CKD was 7.9% (157/1985), with 44 patients experiencing decreased renal function (eGFR less than 60 mL/min/1.73 m²) and 129 patients with albuminuria. Patients with cirrhosis had a higher prevalence of a decreased GFR (4.3% vs 1.6%, P<.001) and albuminuria (11.1% vs 5.2%, P<.001) than those without cirrhosis. In the multivariate analysis, hypertension (Odds Ratio [OR] 4.564, P<.001), diabetes mellitus (OR 2.688, P<.001) and cirrhosis (OR 1.918, P<.001) were independent factors associated with the presence of CKD. CKD was a clinically significant comorbidity in patients with CHB. Special attention should be paid to cirrhotic patients and patients with the metabolic syndrome.

Tenofovir alafenamide as compared to tenofovir disoproxil fumarate in the management of chronic hepatitis B with recent trends in patient demographics

Tenofovir alafenamide (TAF) has recently been approved for chronic hepatitis B (CHB). It is more stable than tenofovir disoproxil fumarate (TDF) in the plasma and can provide similar efficacy with lower circulating concentration in patients with hepatitis B virus (HBV) infection. Areas covered: This synopsis will review the current anti-HBV standard practice and the changing epidemiology of CHB, specifically the controversies surrounding the renal and bone safety associated with TDF use in the context of an aging CHB population. We will review data from phase 3 registration trials, which demonstrated TAF was not inferior to TDF in antiviral efficacy for both HBeAg-positive and HBeAg-negative patients, while associated with less reduction in the estimated glomerular filtration rate and bone mineral density. Expert commentary: Current data supports the use of TAF as one of the first-line antiviral agents for general CHB patients without hepatic decompensation. However, more real-world data with long-term observation are needed to better define the role of TAF among other oral regimens. Additional studies are also needed to evaluate the efficacy and safety of TAF in special populations such as those with impaired hepatic function, existing impaired renal and/or bone function, and in pregnant women.

Renal safety of tenofovir and/or entecavir in patients with chronic HBV monoinfection

Background

Tenofovir disoproxil fumarate (TDF) and entecavir (ETV) are recommended as the first-line therapy for chronic hepatitis B (CHB) due to their genetic barrier to resistance and effectiveness of virological suppression. TDF and ETV may cause renal toxicity through various mechanisms such as renal tubular injury, apoptosis, and mitochondrial toxicity. The aims of the current review were to assess the potential renal toxicity associated with the use of TDF and ETV in patients infected with chronic hepatitis B virus (HBV) and to provide clinical perspectives on these two agents in the treatment of CHB.

Methods

A literature search of clinical studies published in PubMed and posted on ClinicalTrials.gov website was implemented to find studies evaluating the potential renal toxicity of TDF and ETV.

Results

Twenty-one studies were examined in this review. The TDF dose used in the studies was 245 or 300 mg/day and that of ETV was 0.5 or 1 mg/day. Based on the markers of renal function, patients treated with TDF were not more likely to show changes in renal function than those treated with ETV; however, the estimated glomerular filtration rates (eGFRs) of patients receiving TDF tended to be more clearly reduced than those of patients receiving ETV. The eGFRs of patients treated with TDF decreased in a time-dependent manner, whereas those of patients treated with ETV increased or decreased across various time points.

Conclusion

The data shown in this study suggest that use of TDF and ETV could be at least associated with reductions in renal function in patients with chronic HBV infection. However, various risk factors, such as pre-existing renal failure and comorbidities, are also associated with decreased renal function during the treatment of TDF and ETV. Thus, studies of management strategies for HBV-infected patients with these risk factors are necessary in the near future.

Telbivudine attenuates gentamicin-induced kidney injury in rats

Nephrotoxicity has been associated with nucleos(t)ide analogues other than telbivudine (LdT). This study investigated the potential effects of LdT and lamivudine (LAM) on renal function in an experimental rat model of gentamicin-induced acute nephrotoxicity. A total of 28 healthy Wistar albino rats were randomly divided into four experimental groups: negative control; positive control (PC); LdT; and LAM. Nephrotoxicity was induced by gentamicin in the LdT, LAM and PC groups. LdT and LAM were administered to two groups for 6 weeks starting on the ninth day. Blood samples were collected weekly and cystatin C levels were measured by ELISA. Animals were sacrificed on the 50th day and the kidneys were removed for histological examination. Serum cystatin C levels differed significantly between the LdT and LAM groups (P <0.007) and between the LdT and PC groups (P <0.001). Renal function was significantly improved in the LdT group at the start of antiviral treatment on Day 8 and at the end of treatment on Day 50 (P = 0.001 and 0.007). Glomerular injury, acute tubular necrosis and total injury score were significantly reduced in the LdT group relative to the PC and LAM groups upon histopathological examination. LdT was associated with significant improvements in renal function as measured by biochemical and histopathological methods. The acute kidney injury model data should be supported by clinical studies to suggest that LdT treatment may have advantages for patients with underlying chronic kidney disease receiving chronic hepatitis B treatment.

Adverse effects of oral antiviral therapy in chronic hepatitis B

Oral nucleoside/nucleotide analogues (NAs) are currently the backbone of chronic hepatitis B (CHB) infection treatment. They are generally well-tolerated by patients and safe to use. To date, a significant number of patients have been treated with NAs. Safety data has accumulated over the years. The aim of this article is to review and update the adverse effects of oral NAs. NAs can cause class adverse effects (i.e., myopathy, neuropathy, lactic acidosis) and dissimilar adverse effects. All NAs carry a “Black Box” warning because of the potential risk for mitochondrial dysfunction. However, these adverse effects are rarely reported. The majority of cases are associated with lamivudine and telbivudine. Adefovir can lead to dose- and time-dependent nephrotoxicity, even at low doses. Tenofovir has significant renal and bone toxicity in patients with human immunodeficiency virus (HIV) infection. However, bone and renal toxicity in patients with CHB are not as prominent as in HIV infection. Entecavir and lamivudine are not generally associated with renal adverse events. Entecavir has been claimed to increase the risk of lactic acidosis in decompensated liver disease and high Model for End-Stage Liver Disease scores. However, current studies reported that entecavir could be safely used in decompensated cirrhosis. An increase in fetal adverse events has not been reported with lamivudine, telbivudine and tenofovir use in pregnant women, while there is no adequate data regarding entecavir and adefovir. Further long-term experience is required to highlight the adverse effects of NAs, especially in special patient populations, including pregnant women, elderly and patients with renal impairment.

Comparison of telbivudine and entecavir on the change of off- treatment eGFR after 3 years of treatment in non-cirrhotic chronic hepatitis B patients

Background

The change of estimated glomerular filtration rate (eGFR) with off-treatment nucleos(t)ide analogues (NA) in chronic hepatitis B patients (CHB) is unclear. This study is aimed to evaluate the off-treatment eGFR after 3 years of therapy with telbivudine (LdT) or entecavir (ETV) and to assess predictive factors for eGFR improvement.

Methods

From January 2009 to December 2011, we identified NA-naïve patients who were at least 20 years of age diagnosed with compensated CHB. All patients received a 3-year NA treatment and 1 year off-treatment follow-up; the initial selection of patients for LdT or ETV treatment was at the physicians’ discretion. An increase of more than 10% in eGFR from the baseline was identified as an improvement. The change of chronic kidney disease stages were recorded and compared with baseline at year 3 and year 4, respectively.

Results

This study included two groups consisting of 46 patients each (each with3 years of treatment with LdT or ETV). In LdT-treated patients, the mean eGFR increased from 94.3 ± 28.3 to 104.0 ± 31.2 mL/min/1.73 m² in year 3 (p = 0.01) and from 104.0 ± 31.2 to 104.0 ± 28.8 mL/min/1.73 m² in year 4 (p = 0.99). However, in ETV-treated patients, the mean eGFR decreased from 93.1 ± 26.1 to 85.5 ± 25.1 mL/min/1.73 m² in year 3 (p = 0.0009) and from 85.5 ± 25.1 to 87.7 ± 24.8 mL/min/1.73 m² in year 4 (p = 0.2). After a multivariate analysis, the predictors for the off-treatment eGFR improvement were the LdT treatment (odds ratio [OR], 3.97 (1.37–11.5), p = 0.01) and pre-treated eGFR (OR, 0.98 (0.95–1.00), p = 0.04).

Conclusions

At year 4, 48.8 and 21.3% patients had an improved eGFR from baseline in LdT and ETV patients, respectively. Telbivudine may have a protective renal effect that can last for one year after treatment in non-cirrhotic CHB patients without a virological breakthrough.

High rate of hepatitis B viral breakthrough in elderly non-Hodgkin lymphomas patients treated with Rituximab based chemotherapy

BACKGROUND

Rituximab-containing chemotherapies are offered to elderlies for treatment of non-Hodgkin lymphomas (NHL). From 0.7 to 27% of patients with "resolved" HBV infection develop HBV reactivation and related hepatitis during Rituximab-containing chemotherapies. Currently, several antiviral drugs are available for the prophylaxis of patients at risk for HBV reactivation, which include lamivudine, tenofovir, entecavir, and adefovir. Viral breakthrough may occur during therapy, which is defined as an abrupt increase in serum HBV DNA levels after a period of persistent suppression. Viral breakthrough occurs with non-compliance to therapy and, also, when drug-resistant mutants emerge. The risk might be higher in fragile patients as elderlies.

AIMS

Since no study addressed this question, we determined the rate of HBV-RS in patients >65years undergoing Rituximab-containing chemotherapies for NHLs.

METHODS

We evaluated 85 newly diagnosed NHL patients with resolved HBV infection, receiving Rituximab-containing chemotherapies. All received lamivudine. HBV DNA was checked at baseline, every 4 weeks, for 1year after completion of Rituximab cointaining regimens.

RESULTS

Nine patients (10%) had HBV reactivation and HBV related hepatitis. All received entecavir and recovered without consequences. HBV reactivation was more likely to occur after an average of five R-CHOP cycles or during Fludarabine.

CONCLUSIONS

The rate of viral breakthrough (VBK), in our study population, is high considering that the patients were HBV DNA negative at baseline and suggest that Lamivudine prevention may not be sufficient in this population.

Nucleotide Analogue-Related Proximal Renal Tubular Dysfunction during Long-Term Treatment of Chronic Hepatitis B: A Cross-Sectional Study

Background. There have been few reports of nucleotide analogue-related renal tubular dysfunction (RTD) in CHB patients. We assessed the prevalence and presentation of nucleotide analogue-related proximal RTD. Methods. A cross-sectional study was performed in CHB patients taking nucleotide analogues. Inclusion criteria were patients who were on adefovir or tenofovir as mono- or add-on therapy with lamivudine (LAM) >1 year. Serum and urine were collected. Fractional excretion of phosphate (FEPO₄), uric acid (FEUA), and potassium was calculated. Renal losses were defined based on the criteria: protein (24-hour urine protein >150 mg), glucose (glycosuria with normoglycemia), phosphate (FEPO₄ >18%), uric acid (FEUA >15%), potassium (renal potassium losses with hypokalemia), and bicarbonate (normal gap acidosis). Subclinical and overt proximal RTD were defined when 2 and ≥3 criteria presented. Results. Ninety-two patients were enrolled. The mean duration of nucleotide analogue taking was 55.1 ± 29.6 months. Proximal RTD was found in 24 (26.1%) patients (subclinical 15 (16.3%) and overt 9 (9.8%)). The severity of RTD was associated with the duration of nucleotide analogue (P = 0.01). Conclusions. The prevalence of proximal RTD in CHB patients taking nucleotide analogues was 26%. The severity of RTD was associated with the treatment duration. Comprehensive testing is necessary for early detecting nucleotide analogue-related nephrotoxicity.

Editor's Highlight: Comparative Renal Safety Assessment of the Hepatitis B Drugs, Adefovir, Tenofovir, Telbivudine and Entecavir in Rats

The aim of this study was to determine the relative safety of 4 antiviral drugs (telbivudine, tenofovir, adefovir, and entecavir) against hepatitis B virus with respect to kidney function and toxicity in male Sprague Dawley rats. The antiviral drugs were administered once daily for 4 weeks by oral gavage at ∼10 and 25-40 times the human equivalent dose. Main assessments included markers of renal toxicity in urine, magnetic resonance imaging (MRI) of kidney function, histopathology, and electron microscopic examination. Administration of adefovir at 11 and 28 mg/kg for 4 weeks caused functional and morphological kidney alterations in a time- and dose-dependent manner, affecting mainly the proximal tubules and suggesting a mechanism of toxicity related to mitochondrial degeneration/depletion. Of note, the observed adefovir-induced reduction of kidney function was not detected by the standard method of glomerular filtration rate (GFR) measurements (clearance rate of the endogenous marker, creatinine), thereby emphasizing the superiority of MRI in terms of sensitive detection of GFR in rats. For the low dose of 300 mg/kg of tenofovir, minor kidney effects such as nuclear enlargement in the tubular epithelium, and hyaline droplets accumulation were detected, which was also observed for the low dose (11 mg/kg) of adefovir. No assessments could be done at the higher dose of 600/1000 mg/kg tenofovir due to gastrointestinal tract toxicity which prevented treatment of the animals for longer than 1 week. Entecavir at 1 and 3 mg/kg and telbivudine at 600 and 1600 mg/kg caused no toxicologically relevant effects on the kidney.

Tenofovir and kidney transplantation: case report

Background: Hepatitis B viral infection (HBV) has been regarded as a contraindication for kidney transplantation because of the high risk of viral activation induced by immunosuppressive therapy. Anti-retroviral drugs have changed the prognosis of patients with hepatitis B viral infection (HBV+) who are candidates for renal transplant; indeed, therapy with antiretroviral drugs may ensure lower rates of morbidity and mortality compared to traditional therapies. Entecavir is the first-line antiviral therapy recommended for the treatment of HBV+ kidney-transplanted patients. In case of resistance to entecavir, tenofovir may be an alternative drug, either alone or in combination with entecavir. However, the best strategy of treatment is still unknown. In this case-report, a HBV+ kidney-transplanted patient who presented resistance to entecavir was initially treated by associating tenofovir to entecavir and with tenofovir alone afterward. This strategy induced complete remission of viral replication. Case presentation: In a HBV+ kidney-transplanted patient under monotherapy with entecavir, HBV flare (HBV DNA > 170.000 × 10³ UI/mL, HBeAg+, HbeAb–) occurred 9 months after transplantation; at that time, blood chemistry highlighted: creatinine 1.46 mg/dL, blood urea 65 mg/dL, e-GFR 50 mL/min, proteinuria 300 mg/24 h, calciuria 2,12 mmol/24 h, phosphaturia 0.56 g/24 h, vitamin D 11.5 ng/mL, PTH 130 pg/mL, calcemia 2.3 mmol/L, and phosphoremia 2 mg/dL. Liver elastometry (FibroScan) showed moderate fibrosis. Tenofovir was associated to entecavir. Three months after the combination therapy, reduction in HBV DNA replication (351 × 10³ UI/mL) was obtained. Creatinine and e-GFR were 1.48 mg/dL and 52 mL/min, respectively. At this point, entecavir was discontinued. After 13 months of tenofovir monotherapy, complete remission of viral replication was achieved but renal function deteriorated and proteinuria increased. Conclusion: This case-report indicates that tenofovir is effective in reducing viral replication of hepatitis B virus in a kidney-transplanted patient who presented resistance to previous treatment with entecavir. However, it should be taken into account that tenofovir could affect renal function.

Review article: long-term safety of nucleoside and nucleotide analogues in HBV-monoinfected patients

BACKGROUND

Nucleos(t)ide analogues (NUCs) for chronic hepatitis B treatment achieve high rates of viral suppression and are generally well tolerated. Entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are the currently preferred first-line agents. The safety of these agents in clinical practice is particularly relevant since long-term treatment is usually required.

AIM

To summarise and critically discuss recent real-world evidence on the safety of treatment with ETV or TDF in hepatitis B virus (HBV)-monoinfected patients.

METHODS

PubMed and conference proceedings up to 15th June 2015 were searched using the terms ((((Hepatitis_B) OR HBV) AND ((tenofovir) OR entecavir)) AND (((lactic_acidosis) OR bone) OR renal)).

RESULTS

In selected populations included in registration studies, both ETV and TDF were well tolerated with no clinically significant renal toxicity or lactic acidosis. Growing 'real-world' clinical experience with these agents includes some reports of ETV-associated lactic acidosis and TDF-associated renal impairment; however, evidence from cohort studies appears to be conflicting. In the case of ETV-related lactic acidosis, a small number of cases have been reported, all in patients with decompensated cirrhosis. The degree of association between TDF treatment and changes in markers of renal function varies between studies: discrepancies may result from the use of different definitions and cut-offs for reporting renal toxicities, and differences in patient populations.

CONCLUSIONS

Pre-treatment and on-treatment monitoring of eGFR and phosphorus, with prompt appropriate dose adjustment or treatment switch can minimise the impact of NUC renal toxicity. Standardisation of measures of renal impairment and identification of early molecular markers remain an unmet need.

Renal Function in Nucleos(t)ide Analog-Treated Patients With Chronic Hepatitis B: A Systematic Literature Review and Network Meta-Analysis

INTRODUCTION

Renal safety is an important factor in selecting the most appropriate nucleos(t)ide analog (NA) treatment for patients with chronic hepatitis B (CHB). This systematic literature review and network meta-analysis aimed to assess renal function associated with telbivudine treatment compared to other NAs in patients with CHB.

METHODS

A systematic literature search via Medline, Medline In-Process, Embase, and the Cochrane library for publications of randomized controlled trials and observational studies was conducted. Network meta-analysis was performed to compare renal function with telbivudine treatment versus other NAs after 1 year of therapy.

RESULTS

Overall, 40 (six randomized controlled and 34 observational) studies were included for review. Telbivudine consistently showed an improvement in renal function as measured by an estimated glomerular filtration rate (eGFR) over various time points regardless of the method of measurement. Changes in eGFR (mL/min) from baseline and corresponding 95% credible intervals with various NAs were as follows: monotherapies (telbivudine: 7.78 [6.91, 8.65], entecavir: -1.07 [-4.80, 2.62], lamivudine: -6.08 [-13.35, 1.15], tenofovir: -9.53 [-14.31, -4.89]) and combination therapies (telbivudine + adefovir: 8.37 [-34.00, 50.34], telbivudine + tenofovir: 8.29 [-0.05, 16.64], entecavir + adefovir: 4.15 [-38.55, 46.37], telbivudine + lamivudine: 0.51 [-11.77, 12.96], and lamivudine + adefovir: -0.39 [-42.48, 41.21]). At 1 year, the change in eGFR from baseline was significantly higher with telbivudine compared to other NAs.

CONCLUSION

The systematic literature review and network meta-analysis provide evidence that telbivudine is associated with significant improvement in renal function in patients with CHB, either alone or in combination with other NAs.

FUNDING

Novartis Pharma AG.

Potential effects of telbivudine and entecavir on renal function: a systematic review and meta-analysis

Background

To assess the potential effects of telbivudine (LdT) and entecavir (ETV) on renal function in patients with chronic hepatitis B (CHB), we performed a meta-analysis of the relevant data available on these agents to evaluate their effects on the estimated glomerular filtration rate (eGFR) during treatment.

Methods

The PubMed, EMBASE, Scopus, CNKI (China National Knowledge Infrastructure), Cochrane Library, and WanFang databases were searched for relevant articles appearing in the literature up to July 1, 2015. A total of 6 studies (1960 CHB patients) with 1-year eGFR outcomes were retrieved and analyzed.

Results

Generally, the results of the 6 studies analyzed showed that eGFR was improved after LdT treatment, but was decreased after ETV treatment. Using a fixed-effects approach, the change in eGFR was found to be significantly different between LdT and ETV treatment (Z = 3.64; P = 0.0003). Whereas the eGFR was slightly decreased with ETV compared with baseline (−1.45 mL/min/1.73 m²), the eGFR was improved with LdT (2.99 mL/min/1.73 m²) after 1 year of treatment. An overall test of effect in the meta-analysis showed that the eGFR in LdT-treated patients was significantly improved after 1-year of treatment (Z = 3.71; P = 0.0002).

Conclusion

This meta-analysis has confirmed that LdT has a renal protective effect whereas ETV does not. However, whether the benefit on renal function outweighs the occurrence of resistance in specific clinical situations is not yet clear.

Does Nucleos(t)ide Analogues Treatment Affect Renal Function in Chronic Hepatitis B Patients Who Have Already Decreased eGFR? A Longitudinal Study

This study aimed to assess the renal function in chronic hepatitis B (CHB) patients who received nucleos(t)ide analogues (NAs) therapy using estimated glomerular filtration rate (eGFR) titer. We performed a longitudinal observational study of 37 tenofovir-, 42 telbivudine-, and 62 entecavir-naïve CHB patients, who had impaired renal function (eGFR, 90-30 ml/min/1.73m2) without history of diabetes, hypertension, and chemotherapy. Calculation and evaluation of eGFR was performed with the Modification of Diet in Renal Disease, Chronic Kidney Disease Epidemiology Collaboration, and Cockcroft-Gault formula at pretreatment, at baseline, and after the 1st and 2nd year of treatment. The eGFR was significantly increased in patients given telbivudine or entecavir (p = 0.003 and p = 0.012, respectively), but the eGFR was decreased in patients given tenofovir (p = 0.001) after 2 years of treatment. Of all patients, eGFR was stable one year prior to treatment. If we analyzed the renal function by change of chronic kidney disease (CKD) category with a change of 25% of eGFR, the proportion of uncertain drop (drop in CKD category with <25% decrease in eGFR) and certain drop (drop in CKD category with ≧25% decrease in eGFR) in tenofovir group was smaller (5.4%) than those of telbivudine (12.9%) or entecavir (6.5%). Furthermore, telbivudine had the lowest stable rate (76.2%), the highest certain rise rate (9.5%), and certain drop rate (7.1%) compared to the other groups (p = 0.049). In conclusion, in NAs-naïve CHB patients with impaired renal function, telbivudine and entecavir resulted in a significant increase in eGFR while tenofovir resulted in a significant decrease after a 2-year treatment. Interestingly, TDF had the lowest proportion of patients reclassified to certain and uncertain drop groups; in contrast, LdT had a higher proportion in both raise and drop groups. The outcomes of this renal effect remain to be determined.

DNA polymerase inhibitors for treating hepatitis B: a safety evaluation

INTRODUCTION

Oral nucleoside/ nucleotide analogues (NAs) are currently the mainstay of treatment for patients with chronic hepatitis B virus (HBV) infection. They are generally safe to use. However, since their approval in the last decade and a half, the literature has reported adverse effects associated with the use of NA in HBV patients. A comprehensive review on the drug safety is lacking.

AREAS COVERED

Significant adverse effects associated with NA use in HBV patients including muscle toxicity, peripheral neuropathy, nephrotoxicity and lactic acidosis are discussed. The reported prevalence of each adverse effect, as well as their predictive factors, reversibility and their use in pregnancy and lactating mothers are covered in this review. Novel data regarding reno-protective effect of telbivudine are also discussed.

EXPERT OPINION

Use of NA in HBV is generally safe. Uncommon adverse effects can be minimized or detected early if clinicians exercise adequate precautions when using NA for at-risk populations with regular monitoring.

Adefovir- or Lamivudine-Induced Renal Tubular Dysfunction after Liver Transplantation

To reduce hepatitis B virus reinfection after liver transplantation (LT), patients often receive antihepatitis B immunoglobulin (HBIG) alone or combined with antiviral nucleoside/nucleotide analogs (NUCs); however, proximal renal tubular dysfunction (RTD) that was induced by NUCs in liver recipients was rarely reported. Here, we analyzed RTD and renal impairment (RI) following adefovir (ADV) and lamivudine (LAM) treatment in liver recipients. We retrospectively reviewed medical records of patients treated with HBIG alone (group 1, n = 42) or combined with ADV or LAM (group 2, n = 21) after LT. We compared RTD and RI incidence during the 12 months after LT. An RTD diagnosis required manifestation of at least 3 of the following features: hypophosphatemia, RI, hypouricemia, proteinuria, or glucosuria. No significant differences were observed regarding sex, age, donor type, model of end-stage liver score, and estimated glomerular filtration rate at pre-LT between the 2 groups. Hepatitis B virus recurrence within 12 months was 4.8% in both groups (P = 1.000); however, the RTD incidence was 0% in group 1 and 19.0% in group 2 (P = 0.010). RI occurrence did not differ between the groups. The only risk factor for RI was HBIG administration combined with both LAM and ADV (odds ratio 11.27, 95% confidence interval 1.13-112.07, P = 0.039, vs HBIG alone). RTD occurred more frequently in patients treated with HBIG combined with LAM or ADV compared with HBIG alone. Thus, LAM or ADV therapy can induce RTD after LT, and when administered, liver recipients should be monitored.