Renal dysfunction and hypophosphatemia during long-term lamivudine plus adefovir dipivoxil therapy in patients with chronic hepatitis B

Clinical consequence of hypophosphatemia during antiviral therapy for chronic hepatitis B

BACKGROUND

Antiviral therapy is an essential treatment for chronic hepatitis B (CHB) infection. Although hypophosphatemia is an important adverse effect of antiviral agents, its clinical significance remains unclear. We investigated the incidence and clinical consequences of hypophosphatemia in a large cohort of CHB patients.

METHODS

This retrospective cohort study included CHB patients who started antiviral therapy between 2005 and 2015 and continued it for at least 1 year. Patients with decompensated liver cirrhosis, diabetes mellitus, hypertension, concomitant diuretic administration, and end-stage renal disease were excluded. The primary outcome was a change in renal function. Secondary outcomes included the incidence of infection and changes in serum potassium, uric acid, and total carbon dioxide (tCO2).

RESULTS

Among the 4,335 patients, hypophosphatemia developed in 75 (1.7%). During the median 2-year follow-up period, patients with hypophosphatemia showed a lower estimated glomerular filtration rate than those in the control group. The incidence of infection and changes in serum potassium, uric acid, and tCO2 were similar between groups.

CONCLUSION

Hypophosphatemia was associated with a renal function decline in patients with CHB receiving antiviral therapy.

Follow-Up of Adefovir Dipivoxil Induced Osteomalacia: Clinical Characteristics and Genetic Predictors

Adefovir dipivoxil (ADV) is widely used for chronic hepatitis B therapy in China. To explore the clinical features and prognosis of ADV-induced osteomalacia and to analyze the association between osteomalacia and genetic variants in 51 drug transporters genes. Clinical and follow-up data of the ADV-treated patients were collected. Target capture sequencing was used to identify genetic variations of 51 drug transporter genes. A total of 193 hepatitis B patients treated with ADV were enrolled, of whom 140 had osteomalacia. The other 53 without osteomalacia were included in the control group. The median duration of ADV treatment before the onset of osteomalacia was 6.5 years (range:1.5–7 years). We found that most patients with osteomalacia had hypophosphatemia, high serum alkaline phosphatase levels, hypouricemia, nondiabetic glycosuria, proteinuria. Stopping ADV administration, supplementing calcitriol and calcium were effective treatments. During 3–6 months of follow-up, the clinical symptoms and biochemical indicators of patients with osteomalacia have been significantly improved. There was no significant difference in duration of adefovir treatment in patients with or without osteomalacia (p = 0.791). Through regression analysis, we found that age was a risk factor for osteomalacia [per 1 year, odds ratio (OR), 1.053; 95% confidence interval (95% CI), 1.020–1.087; p = 0.015]. 1992 single nucleotide variants were found using target capture sequencing. However, the associations of genetic variants of 51 drug transporter genes and the risk of osteomalacia were negligible. Osteomalacia is prone to occur in patients with chronic hepatitis B treated with long-term ADV at a therapeutic dose. After standard treatment, the prognosis is mostly good. We failed to find genetic variants that can predict the risk of ADV-induced osteomalacia.

Tenofovir Alafenamide Rescues Renal Tubules in Patients with Chronic Hepatitis B

Nucles(t)ide analogs (NAs) are effective for chronic hepatitis B (CHB). NAs suppress hepatic decompensation and hepatocarcinogenesis, leading to a dramatic improvement of the natural course of patients with CHB. However, renal dysfunction is becoming an important issue for the management of CHB. Renal dysfunction develops in patients with the long-term treatment of NAs including adefovir dipivoxil and tenofovir disoproxil fumarate. Recently, several studies have reported that the newly approved tenofovir alafenamide (TAF) has a safe profile for the kidney due to greater plasma stability. In this mini-review, we discuss the effectiveness of switching to TAF for NAs-related renal tubular dysfunction in patients with CHB.

Kinetics of hepatitis B surface antigen and estimated glomerular filtration rate in telbivudine-treated hepatitis B patients with different rescue strategies

This study investigated the kinetics of estimated glomerular filtration rate (eGFR) and quantitative hepatitis B surface antigen (qHBsAg) in telbivudine (LdT)-treated chronic hepatitis B (CHB) patients whose treatment was subsequently adjusted with the adding on adefovir or by switching to tenofovir disoproxil fumarate (TDF) as rescue. Of 295 CHB patients initially treated with LdT, 102 of them who subsequently receiving either adding-on adefovir (group A, n = 58) or switching to TDF (group B, n = 44) for more than 24 months were enrolled. Serial eGFR and qHBsAg levels (3 to 6 monthly) in both LdT monotherapy and rescue therapy periods were analyzed retrospectively. Subsequent decline of qHBsAg especially in rescue therapy period were noted (p<0.001 and p = 0.068 in group A and B). However, patients in group B achieved a significant increase of eGFR (p = 0.010) in LdT monotherapy period but had a significant decline of eGFR (p<0.001) in rescue therapy period. In contrast, patients in group A maintained eGFR levels in both periods. Meanwhile, switch to TDF (hazard ratio: 3.036; 95% confidence interval: 1.040-8.861; p = 0.042) was the sole factor related to the decrease of eGFR>20% from baseline. Both rescue therapies achieved subsequent declines of qHBsAg over time but caused different changes in eGFR. LdT-based rescue therapy maintained eGFR but TDF switching therapy descended eGFR. Therefore, it is essential to monitor patient's renal function intensively when switching from LdT to TDF as a rescue strategy.

Retrospective analysis of the clinical characteristics of adefovir dipivoxil-induced Fanconi's syndrome in the Chinese population

WHAT IS KNOWN AND OBJECTIVE

To explore the clinical characteristics of adefovir dipivoxil-induced Fanconi's syndrome in the Chinese population and provide a reference for rational drug use in the clinic.

METHODS

By searching the CNKI, Wanfang, Chinese VIP, PubMed/MEDLINE, Web of Knowledge, Ovid, Elsevier and SpringerLink databases during 1 January 2008 to 31 December 2019, 78 studies of ADV-induced Fanconi's syndrome involving a total of 110 patients were collected and analysed retrospectively.

RESULTS AND DISCUSSION

Prolonged usage of adefovir dipivoxil at low doses to treat hepatitis B might cause Fanconi's syndrome as the first symptom, especially for use over 12 months.The main clinical manifestation was bone pain accompanied by hypophosphataemia, elevated alkaline phosphatase (ALP), urine glycosuria and urine protein. X-rays and bone mineral density (BMD) examinations were mainly used to characterized osteoporosis. The patients had pain relief within 1 week to 1 month, and the biochemical indicators returned to normal within from 2 to 4 months.

WHAT IS NEW AND CONCLUSION

Sufficient attention is required before and during exposure to long-term ADV therapy. The clinical picture, laboratory and radiograph alterations are important clues for ADV-induced Fanconi's syndrome.

Hypophosphatemic Osteomalacia Associated with Adefovir-induced Fanconi Syndrome Initially Diagnosed as Diabetic Kidney Disease and Vitamin D Deficiency

A 68-year-old man with type 2 diabetes mellitus and chronic hepatitis B infection was referred to the nephrology department before planned surgery for hepatocellular carcinoma. He had been receiving low-dose adefovir dipivoxil (ADV) for 11 years. Laboratory findings revealed impaired re-absorption in the proximal renal tubules. He had been diagnosed with diabetic kidney disease and osteomalacia due to vitamin D deficiency; thus, ADV was not discontinued until he was referred to us. In this case, concomitant diabetes mellitus and vitamin D deficiency might have prevented the early diagnosis of ADV-induced Fanconi syndrome.

Adefovir dipivoxil induced hypophosphatemic osteomalacia in chronic hepatitis B: a comparative study of Chinese and foreign case series

BACKGROUND

Adefovir dipivoxil (ADV)-induced renal tubular dysfunction and hypophosphatemic osteomalacia (HO) have been given great consideration in the past few years. However, no standard guidance is available due to a lack of powerful evidence from appropriate long-term prospective case-control studies and variations in the definition of renal adverse events. The aim of this study is to clarify clinical features of ADV-related HO in Chinese chronic hepatitis B patients with long-term ADV treatment in Chinese and non-Chinese comparative case series.

METHODS

Retrieval of case reports was based on Pubmed, CNKI, Wan Fang and VIP databases using the key words adefovir dipivoxil, hypophosphatemia, osteomalacia and Fanconi syndrome. We divided patients into Chinese (C group) and Foreign (F group) groups according to their nationality. Comparisons involving demographics, clinical manifestations, tests, treatment and prognosis were conducted between the two groups.

RESULTS

Of the patients screened, 120 Chinese patients were identified in the C group, and 32 non-Chinese patients were identified in the F group. The average age of the C group was younger than that of the F group (51.89 years ±10.96 years versus 56.47 years ±11.36 years, t = - 2.084, P = 0.039). No significant difference was found in gender (male to female, 3.29:1 versus 3:1, χ ²  = 0.039, P = 0.844). Although there was no significant difference in the duration of ADV therapy before ostalgia onset, the C group tended to develop adverse events earlier, by 2-3 years, while the F group developed adverse events at 4-5 years (Z = - 1.517, P = 0.129). Prognosis was good after adjustment of the ADV dose and supplemental administration of phosphate and calcitriol. Time to resolution of tubular dysfunction was commenced at the first month, and Chinese patients were more prone to recover in the first 3 months than non-Chinese patients (91.3% of patients in the C group versus 56.3% in the F group, Z = - 3.013, P = 0.003).

CONCLUSIONS

Sufficient attention is required for middle-aged males before and during exposure to long-term ADV therapy, regardless of nationality. The clinical picture, laboratory and radiograph alterations are important clues for those patients and are usually characterized by polyarthralgia, renal tubular dysfunction and mineralization defects. Implementation of an early renal tubular injury index is recommended for patients with higher risk, which would prevent further renal injury.

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.

Reversal of Proximal Renal Tubular Dysfunction after Nucleotide Analogue Withdrawal in Chronic Hepatitis B

Aims

Proximal renal tubular dysfunction (PRTD) is an infrequent complication after nucleotide analogue therapy. We evaluated the outcomes of PRTD and nephrotoxicity after nucleotide analogue withdrawal in chronic hepatitis B (CHB).

Methods

A longitudinal follow-up study was performed in patients with PRTD after nucleotide analogue discontinuation. Serum and urine were collected at baseline and every 3 months for one year. The fractional excretion of phosphate (PO₄), uric acid (UA), and potassium and tubular maximal reabsorption rate of PO₄ to glomerular filtration rate (TmPO₄/GFR) were calculated. Renal losses were defined based on the criteria of substance losses. Subclinical PRTD and overt PRTD were diagnosed when 2 and ≥3 criteria were identified.

Results

Eight subclinical and eight overt PRTD patients were enrolled. After nucleotide analogue withdrawal, there were overall improvements in GFR, serum PO₄, and UA. Renal loss of PO₄, UA, protein, and β2-microglobulin reduced over time. At one year, complete reversal of PRTD was seen in 13 patients (81.2%). Improvements in PRTD were seen in all but one patient.

Conclusion

One year after nucleotide analogue withdrawal, PRTD was resolved in most patients. Changes in TmPO₄/GFR, urinary protein, and β2-microglobulin indicate that urinary biomarkers may represent an early sign of PRTD recovery.

Factors Related to Significant Improvement of Estimated Glomerular Filtration Rates in Chronic Hepatitis B Patients Receiving Telbivudine Therapy

BACKGROUND AND AIM

The improvement of estimated glomerular filtration rates (eGFRs) in chronic hepatitis B (CHB) patients receiving telbivudine therapy is well known. The aim of this study was to clarify the kinetics of eGFRs and to identify the significant factors related to the improvement of eGFRs in telbivudine-treated CHB patients in a real-world setting.

METHODS

Serial eGFRs were calculated every 3 months using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The patients were classified as CKD-1, -2, or -3 according to a baseline eGFR of ≥90, 60-89, or <60 mL/min/1.73 m2, respectively. A significant improvement of eGFR was defined as a more than 10% increase from the baseline.

RESULTS

A total of 129 patients were enrolled, of whom 36% had significantly improved eGFRs. According to a multivariate analysis, diabetes mellitus (DM) (p = 0.028) and CKD-3 (p = 0.043) were both significantly related to such improvement. The rates of significant improvement of eGFR were about 73% and 77% in patients with DM and CKD-3, respectively.

CONCLUSIONS

Telbivudine is an alternative drug of choice for the treatment of hepatitis B patients for whom renal safety is a concern, especially patients with DM and CKD-3.

Relationship between nephrotoxicity and long-term adefovir dipivoxil therapy for chronic hepatitis B: A meta-analysis

BACKGROUND

To assess the relationship between adefovir dipivoxil and renal function after anti-hepatitis B virus therapy and elucidate the risk factors involved.

METHODS

Based on the requirements of the Cochrane systematic review methodology, 21 observational articles on adefovir dipivoxil-associated renal dysfunction were obtained by searching various databases, between January 1, 1995 and July 1, 2016. The Newcastle Ottawa Scale was used to evaluate risk bias. Parameters for 4276 chronic hepatitis B patients were analyzed by Review Manager and R software, and glomerular filtration rate, creatinine clearance, and serum creatinine values were extracted to evaluate renal function.

RESULTS

Renal dysfunction was more likely to occur in patients receiving the adefovir dipivoxil therapy (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.40-2.80) than the none-adefovir dipivoxil group. Subgroup analysis showed that renal function predictive value is higher for glomerular filtration rate (OR 2.42, 95% CI 1.34-3.14), compared with serum creatinine levels (OR 1.51, 95% CI 0.75-3.04). The rate of adefovir dipivoxil-associated renal dysfunction was 12% (95% CI 0.08-0.16). Older patients and patients with renal insufficiency, hypertension, and diabetes mellitus were more prone to developing adefovir dipivoxil-associated renal dysfunction; however, integrated raw data were insufficient for further detailed analysis.

CONCLUSION

Long-term adefovir dipivoxil therapy is connected to renal dysfunction in chronic hepatitis B, necessitating the monitoring of kidney function.

Circulating kidney injury molecule-1 is a novel diagnostic biomarker for renal dysfunction during long-term adefovir therapy in chronic hepatitis B

The aim of this study was to evaluate serum kidney injury molecule-1 (KIM-1) as a new diagnostic marker of renal dysfunction in chronic hepatitis B (CHB) patients receiving long-term adefovir dipivoxil (ADV) treatment.We retrospectively enrolled 85 patients treated with ADV and 85 patients treated with entecavir (ETV) monotherapy, for at least 6 months. The 2 groups were matched for baseline age (± 5 years), sex, and estimated glomerular filtration rate (eGFR). Serum creatinine, cystatin C, and KIM-1 concentrations were measured, and eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine-cystatin C equation, at baseline and last follow-up.eGFR decreased by 10-20% from baseline in 11/85 (14.1%) patients, 20-30% in 5/85 (5.9%), and ≥ 30% in 2/85 (2.4%) patients treated with ADV. Serum KIM-1 was more significantly increased after ADV treatment 86.53 (10.20-355.40) pg/mL than ETV treatment 61.54 (10.53-200.56) pg/mL (P < 0.01). Furthermore, serum KIM-1 was positively correlated with serum cystatin C (r = 0.47; P < 0.001) and negatively correlated with eGFR (r = -0.46; P < 0.001). The area under the receiver operating characteristic curve (AUC-ROC) of serum KIM-1 for identifying renal dysfunction in all enrolled patients was 0.94 (95% confidence interval [95% CI], 0.87 to 1.02; P < 0.001), while the AUC-ROC of serum creatinine was only 0.82 (95% CI, 0.60 to 1.03; P < 0.01).Serum KIM-1 is a promising new diagnostic biomarker of renal dysfunction during long-term ADV therapy for CHB patients.

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.

Hepatitis B Reactivation with Novel Agents in Non-Hodgkin's Lymphoma and Prevention Strategies

Hepatitis B virus (HBV) infection remains an endemic disease in most parts of the world despite available prophylactic vaccines. Non-Hodgkin's lymphoma is the most common hematological malignancy, and certain patients undergoing therapy are at increased risk of HBV reactivation. Rituximab, a monoclonal antibody, is well studied in HBV reactivation, but newer agents have been implicated as well. Here, we review novel agents suspected in HBV reactivation and effective strategies to prevent HBV reactivation. Fifteen years of literature were reviewed in order to better understand the reactivation rates of hepatitis B in patients with non-Hodgkin's lymphoma. Anti-CD20 antibodies continue to be the main medications that can lead to HBV reactivation, and HBV reactivation rates have decreased with increased awareness. HBV reactivation is uncommon when using other novel agents. Entecavir and lamivudine remain the agents of choice to prevent HBV reactivation in high risk patients. In conclusion, the immunosuppressive effect of NHL and its therapy provide a pathway for HBV reactivation, especially in patients treated with anti-CD20 antibody. Since many HBV positive patients are often excluded from clinical trials of novel agents in NHL, more aggressive post-market surveillance of new agents, well-designed best practice advisories, and timely case reports are needed to reduce the incidence of HBV reactivation. Lastly, large prospective investigations coupled with well-utilized best practice advisories need to be conducted to understand the impact of more potent novel NHL therapy on HBV reactivation.

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.

Nucleos(t)ide analogues for the prevention of hepatitis B recurrence after liver transplantation do not affect serum phosphorus levels

BACKGROUND

Nucleos(t)ide analogues (NAs) constitute the backbone of treatment for the prevention of hepatitis B virus recurrence after liver transplantation (LT). Decline in serum phosphorus levels is a common side effect of nucleotide therapy. Our aim was to assess the impact of nucleotide treatment on the occurrence of hypophosphatemia after LT and determine possible predictors.

METHODS

We retrospectively analyzed data from liver transplant recipients who had been transplanted for various indications. All patients were evaluated every 3 months. Each patient was considered to be having hypophosphatemia when at least one value of serum phosphorus ≤2.5 mg/dL was detected.

RESULTS

In total, 109 patients [83 males (76%)] with a mean age of 55±10 years were included. 46/67 (67%) patients with hepatitis B received a nucleotide. The rate of hypophosphatemia (55%) was not different between patients with hepatitis B and those transplanted for other indications (62%). Patients receiving a nucleotide did not run a greater risk of hypophosphatemia than patients receiving only nucleosides (59% vs. 48%, P=0.39). Male gender and everolimus use were associated with the occurrence of hypophosphatemia in patients with hepatitis B. In multivariate analysis only gender was associated with hypophosphatemia (odds ratio 11.43, 95%CI -2.11 to -0.49; P=0.0025).

CONCLUSIONS

Hypophosphatemia occurs in more than half of liver transplant recipients regardless of the indication for LT. Male gender and everolimus use seem to predispose to hypophosphatemia, whereas the type of antiviral agent does not.

Outcome of adefovir add-on lamivudine rescue therapy of up to 5 years in patients with lamivudine-resistant chronic hepatitis B

BACKGROUND AND AIM

We investigated the long-term efficacy of adefovir add-on lamivudine rescue therapy in lamivudine-resistant chronic hepatitis B and the optimal cutoff hepatitis B virus (HBV) DNA level that predicts complete virological response (CVR) among patients without CVR after 1 year of treatment.

METHODS

We reviewed 167 lamivudine-resistant chronic hepatitis B patients who received adefovir add-on rescue therapy for up to 5 years. Multivariate analysis, area under the receiver operating characteristic curves, and Youden index were used.

RESULTS

Median age was 47.0 years; 112 patients were male. Median baseline HBV DNA level was 6.6 log10 IU/mL; hepatitis B e antigen was positive in 130 (77.4%) patients. Five-year CVR, alanine aminotransferase normalization, hepatitis B e antigen seroconversion, and adefovir resistance rates were 86.9%, 92.5%, 16.7%, and 6.0%, respectively. One-year HBV DNA level independently associated with CVR. Optimal cutoff HBV DNA level to predict CVR among patients who failed to achieve CVR at 1 year was 800 IU/mL (area under receiver operating characteristic curve 0.752; sensitivity 49.3%, specificity 93.5%). During the 5-year treatment, 92.1% of patients with favorable response (HBV DNA < 800 IU/mL at 1 year) achieved CVR; 45.6% achieved CVR among suboptimal responders (HBV DNA ≥ 800 IU/mL at 1 year) (P < 0.001).

CONCLUSION

Complete virological response or HBV DNA level < 800 IU/mL after 1 year adefovir add-on lamivudine rescue therapy can favorably predict CVR.

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.

Comparison of entecavir monotherapy and de novo lamivudine and adefovir combination therapy in HBeAg-positive chronic hepatitis B with high viral load: 48-week result

This study compared virologic response to entecavir monotherapy and de novo lamivudine plus adefovir (LAM + ADV) combination therapy in patients with chronic hepatitis B (CHB) with high viral load (HVL). Hepatitis B e antigen (HBeAg)-positive patients [hepatitis B virus (HBV) DNA levels >1 × 10(7) copies/ml] were assigned to LAM + ADV or entecavir treatment. The primary efficacy endpoint measure of the multicenter prospective cohort study was proportion of patients with CHB with virologic response, defined as HBV DNA <300 copies/ml at week 48. During treatment, 39.1 % (18/46) of patients in the LAM + ADV group and 48.1 % (25/52) of those in the entecavir group achieved virologic response in week 48 (P = 0.37). A baseline alanine aminotransferase (ALT) level ≥5 × ULN (upper limit of normal) or baseline serum HBV DNA level <8 log10 IU/ml could predict virologic response at week 48 (P = 0.025). The mean reduction in HBV DNA was comparable (P = 0.45); no significant difference was found in the proportion of ALT normalization (P = 0.46) or HBeAg seroconversion (P = 0.88). Two cases of genotypic resistance were found (rtM204 V + rtL180 M and rtA181T/V) in the LAM + ADV group, with a resistance rate of 4.3 %; there was no genotypic resistance in the entecavir group (P = 0.13). De novo LAM + ADV combination therapy is as effective as entecavir monotherapy in HBeAg-positive patients with CHB with HVL. Moreover, genotypic resistance was only found in the LAM + ADV group at week 48. Baseline ALT levels ≥5 ULN or baseline serum HBV DNA levels <8 log10 IU/ml were favorable predictors of virologic response in CHB with HVL.

Current and future directions for treating hepatitis B virus infection

Hepatitis B virus (HBV) persistently infects approximately 350 million people, and approximately 600000 liver-related deaths are observed per year worldwide. HBV infection is also one of the major risk factors for hepatocellular carcinoma (HCC). The persistence of serum hepatitis B e antigen (HBeAg) and high level of serum HBV DNA are thought to reflect a high HBV replication status in hepatocytes, causing cirrhosis, HCC and liver-related deaths. It has been reported that antiviral therapy, such as peginterferon and nucleos(t)ide analogues (NUCs), could suppress liver-related death by inhibiting the HBV DNA levels and inducing seroconversion from HBeAg to antibody to HBe antigen. Currently, peginterferon is widely used, but there are also several disadvantages in the use of peginterferon, such as various adverse events, the administration route and duration. It is difficult to predict the effects of treatment and interferon is contraindicated for the patients with advanced fibrosis of the liver and cirrhosis. With respect to NUCs, entecavir and tenofovir disoproxil fumarate are current the first-choice drugs. NUCs can be administered orally, and their anti-viral effects are stronger than that of peginterferon. However, because cessation of NUC administration leads to high levels of viral replication and causes severe hepatitis, they must be administered for a long time. On the other hand, the use of both interferon and NUCs cannot eliminate covalently closed circular DNA of HBV. In this review, we evaluate the natural course of chronic HBV infection and then provide an outline of these representative drugs, such as peginterferon, entecavir and tenofovir disoproxil fumarate.

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

AIM: To evaluate urine β2-microglobulin (β2-M), retinol-binding protein (RBP) excretion, and renal impairment with adefovir dipivoxil (ADV) for chronic hepatitis B.

METHODS: We enrolled 165 patients with chronic hepatitis B infection who were treated with ADV monotherapy (n = 90) or ADV plus lamivudine combination therapy (n = 75). An additional 165 chronic hepatitis B patients treated with entecavir were recruited as controls. We detected serum creatinine, urine β2-M, and RBP levels, and estimated the glomerular filtration rate (eGFR) at the initiation of antiviral therapy and every 6 mo for a period of five years.

RESULTS: Urine β2-M abnormalities were observed in patients during the first (n = 3), second (n = 7), third (n = 11), fourth (n = 16), and fifth (n = 21) year of ADV treatment. Urinary RBP abnormalities were observed in patients during the first (n = 2), second (n = 8), third (n = 12), fourth (n = 15), and fifth (n = 22) year of ADV treatment. eGFR decreased 20%-30% from baseline in 20 patients, 30%-50% in 12 patients, and > 50% in 3 patients during the five years of treatment. Further analysis indicated that decreases in eGFR of ≥ 30% relative to the baseline level correlated significantly with urine RBP and β2-M abnormalities. In contrast, both serum creatinine and eGFR remained stable in patients treated with entecavir, and only one of these patients developed a urine β2-M abnormality, and two developed urine RBP abnormalities during the five years of treatment.

CONCLUSION: Urine RBP and β2-M are biomarkers of renal injury during long-term ADV treatment for chronic hepatitis B, and indicate when treatment should be switched to entecavir.

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

BACKGROUND

Results are conflicting with respect to the renal effects of anti-viral agents used for hepatitis B virus infection.

AIM

To compare short and long-term renal effects in real-life settings and to determine risk factors for renal impairment during treatment.

METHODS

2221 treatment-naïve patients were enrolled. Among these, 895 (302 lamivudine, 27 telbivudine, 282 entecavir, 273 tenofovir and 11 adefovir initiated patients) had 'repeated measures' of creatinine (baseline, 1st, 6th, 12th and 24th month of treatment). Telbivudine and adefovir groups were excluded from further analysis because of the low number of patients. We calculated the glomerular filtration rate (GFR) using the Modification of Diet in Renal Disease (MDRD) formula at each time point. Hypophosphataemia was also recorded. Risk factors for renal impairment were analysed.

RESULTS

Tenofovir caused a decline in GFR at each time point when compared to baseline levels. However, lamivudine and entecavir did not change GFR. GFR-shifting from ≥90 to 60-89 mL/min/1.73 m(2) was comparable among groups. The proportion of patients whose baseline creatinine increased more than 25% was comparable among all anti-virals. GFR showed a decline in patients who switched from entecavir to tenofovir. One patient with compensated cirrhosis needed to change from tenofovir because of renal safety. Seven and three patients developed transient hypophosphataemia in the tenofovir and lamivudine groups, respectively.

CONCLUSIONS

Although tenofovir caused a decline in GFR, differences between the anti-viral agents do not appear to be so impressive. In patients with and without renal risk factors at baseline, there is no impact of anti-virals, including tenofovir.

Association between adefovir dipivoxil treatment and the risk of renal insufficiency in patients with chronic hepatitis B: A meta-analysis

Adefovir dipivoxil (ADV) is an effective antiviral drug against hepatitis B virus. The renal tolerance of ADV at the currently approved dose of 10 mg daily for the treatment of chronic hepatitis B (CHB) remains controversial. The present meta-analysis was therefore performed to evaluate the renal safety of ADV treatment in patients with CHB. Two independent investigators searched MEDLINE, Embase and China National Knowledge Infrastructure databases for eligible studies published in English or Chinese until June 1, 2014. The Peto odds ratios (Peto ORs) or the rates of each study were analyzed. Seven randomized controlled trials (RCTs), four cohort studies and six single-arm studies were identified. ADV treatment was not associated with a higher incidence of nephrotoxicity in RCTs [Peto OR, 1.781; 95% confidence interval (CI), 0.637-4.979; P=0.271] but appeared to increase nephrotoxicity significantly in cohort studies (Peto OR, 2.682; 95% CI, 1.470-4.894; P=0.001); the significant increase was further observed in CHB patients receiving long-term ADV treatment in cohort studies (Peto OR, 2.275; 95% CI, 1.127-4.593; P=0.022). The analysis based on single-arm studies showed that the rate of renal dysfunction in the ADV-treated patients was 10.6% (95% CI, 0.059-0.185); the subgroup analysis with the standard of createnine levels showed a lower rate (6.9%, 95% CI, 0.013-0.298) than those in the overall studies. In conclusion, although current evidence indicated a positive link between treatment with ADV in CHB patients and an increased risk of renal dysfunction, optimally designed studies are required for definitive conclusions.

Acquired Fanconi syndrome due to long-term adefovir administration in a patient with IgG-kappa monoclonal gammopathy and kappa Bence-Jones protein

A 77-year-old man was admitted to our hospital for a right femoral neck fracture. He had been prescribed lamivudine for chronic hepatitis B infection for 11 years, and adefovir was added 5 years ago. After hospitalization, a right femoral head prosthesis was performed successfully, but an unknown hypokalemia was revealed. Hypophosphatemia, hypouricemia, glucosuria, and panaminoaciduria were also revealed, and multiple microfractures were detected by bone scintigraphy. We diagnosed him as 'osteomalacia associated with Fanconi syndrome,' which was likely due to the adefovir. Moreover, a monoclonal IgG-kappa and a kappa Bence-Jones protein were detected in his serum and urine, respectively. We switched from adefovir plus lamivudine to entecavir and started calcitriol. His excessive urinary β2-microglobulin excretion and glucosuria had decreased dramatically at 10 weeks after the modification of drugs; those of the phosphate, uric acid and total protein, however, continued. Renal biopsy specimens obtained at 10 weeks after discontinuation of adefovir revealed focal tubular atrophic changes with/without inflammatory cells, which were predominantly observed next to glomeruli. Kappa-dominant staining was not observed in either glomeruli or tubules with immunostaining by the enzyme-labeled antibody method. Electron microscopy revealed neither crystalline structures in the cytoplasm of proximal tubules nor electron-dense deposits. Because of the remarkable proportional reduction of other urinary protein fractions, urinary M-peak appeared 26 weeks after discontinuation of adefovir, but the net amounts of the fraction decreased gradually.

Telbivudine prophylaxis for hepatitis B virus recurrence after liver transplantation improves renal function

INTRODUCTION

Renal impairment after liver transplantation represents an important issue in the management of transplantation patients, particularly when those subjects may need prophylaxis for fungal or viral infection. Herein we report our experience with 12 transplantation patients receiving telbivudine 600 mg/d while on the waiting list, followed by treatment for 18 months after liver transplantation, showing an improvement on their renal function during the follow-up period.

METHODS

Our series consisted of men with hepatitis B virus (HBV)-related end-stage liver disease. The viral load decreased rapidly while on the waiting list once the patient was started on antiviral treatment. Those subjects were compared with 12 patients on lamivudine prophylaxis. All patients were evaluated for liver and renal function, immunosuppression trough levels, and creatine phosphokinase (CPK) before liver transplantation (T0) and at 3, 6, 12, and 18 months (T3, T6, T12, T18).

RESULTS

All patients received a calcineurin inhibitor immunosuppression-based regimen. Creatinine clearance (Modification of Diet in Renal Disease) was 67 mL/min at T0, with a statistically significant improvement after month 6 compared with those on lamivudine and with the value at the beginning of the prophylaxis (Mann-Whitney U test P<.05). Neither CPK nor transaminase serum levels increased throughout the study period. Once HBV DNA was cleared while on the waiting list, it remained negative throughout the follow-up period.

CONCLUSIONS

Telbivudine prophylaxis for HBV is safe and effective, without any significant deleterious effect on the liver; on the contrary, it seems to improve renal function after liver transplantation through 18 months. Further studies and larger series are warranted to confirm these findings.