Significance of switching of the nucleos(t)ide analog used to treat Japanese patients with chronic hepatitis B virus infection from entecavir to tenofovir alafenamide fumarate

Switching from combination therapy with entecavir hydrate plus tenofovir alafenamide fumarate to tenofovir alafenamide fumarate monotherapy in patients with chronic hepatitis B based on nucleotide sequences of hepatitis B virus pregenome RNA

AIM

Patients with chronic hepatitis B virus (HBV) infection experiencing viral breakthrough (BTH) or partial response (PR) during lamivudine (LAM) or entecavir hydrate (ETV) administration often took ETV plus tenofovir alafenamide fumarate (TAF) due to the emergence of a drug-resistance mutation. However, in patients lacking drug-resistance mutation against TAF, sufficient antiviral effects may be achievable with TAF monotherapy. We assessed the drug-resistance profile through nucleotide sequences of HBV pregenome RNA, and subsequently changed to TAF monotherapy from ETV plus TAF.

METHODS

This prospective study included 25 patients with serum HBV-DNA below 20 IU/mL under ETV plus TAF administration. Pregenome RNA nucleotide sequences of HBV in the sera were analyzed using direct sequencing and deep sequencing. ETV was discontinued in patients without rtA194T and rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutations in direct sequencing.

RESULTS

LAM-PR, LAM-BTH, ETV-PR, and ETV-BTH were observed in 1, 16, 7, and 1 patient(s), respectively. Pregenome RNA nucleotide sequences were analyzable in 20 patients. Among the 12 patients classified as LAM-BTH, six patients showed rtL180M + rtM204V/I in direct sequencing, and one patient showed minor clones containing rtL180M + rtM204V + A194T in deep sequencing at a frequency of 0.3%. In the six patients classified as ETV-PR, one patient harbored rtM204I. No clones showing rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutation were detected in deep sequencing. Subsequently, ETV was discontinued, and serum HBV-DNA remained undetectable up to 48 weeks in all patients.

CONCLUSION

Patients receiving ETV plus TAF due to partial response or BTH during initial LAM or ETV administration were able to safely transition to TAF monotherapy based on nucleotide sequences of HBV pregenome RNA in the sera.

Increased spine bone density in patients with chronic hepatitis B switched to tenofovir alafenamide: A prospective, multinational study

BACKGROUND

Data on patients switched to tenofovir alafenamide (TAF) from nucleos(t)ide analogues (NUCs) other than tenofovir disoproxil fumarate are limited.

AIMS

To assess the treatment and renal/bone safety outcomes following the switch to TAF.

METHODS

We prospectively enrolled adult patients with chronic hepatitis B (CHB) who switched from any NUC to TAF at 14 centres in Japan, Korea, Taiwan and the U.S. Study outcomes were viral suppression (VR; HBV DNA < 20 IU/mL), biochemical response (BR; alanine aminotransferase normalisation), and changes in estimated glomerular filtration rate (eGFR) and T-scores (L-spine) by bone absorptiometry by 24 months after switch to TAF.

RESULTS

We enrolled 270 eligible patients. Mean age was 58.1; 58.2% were male; 12.2% had cirrhosis and 73.3% previously received entecavir monotherapy. VR rate increased significantly from 95.2% to 98.8% by 24 months after the switch to TAF (p = 0.014). Between the switch and 24 months later, the mean spine T-score improved significantly from -1.43 ± 1.36 to -1.17 ± 1.38 (p < 0.0001), while there was no significant change in mean eGFR (88.4 ± 16.9-89.5 ± 16.3 mL/min/1.73 m2 , p = 0.13). On multivariable analysis adjusted for age, sex, baseline spine T-score and prior TDF or adefovir dipivoxil use, male sex was significantly associated with lower risk of worsening spine T-score (odds ratio: 0.29, p = 0.020), while age was significantly associated with a higher risk of worsening chronic kidney disease stage (OR: 1.07, p = 0.019).

CONCLUSIONS

At 24 months after the switch to TAF, VR rates and spine bone density improved significantly while renal function remained stable.

Real-World Epidemiology, Clinical and Economic Burden of Chronic Hepatitis B in Japan: A Retrospective Study Using JMDC Claims Database

INTRODUCTION

Chronic hepatitis B (CHB) is one of the world's major healthcare problems, especially in the Western Pacific regions. This study describes the prevalence, incidence, treatment profiles and clinical and economic burden of chronic hepatitis B patients in Japan using the Japan Medical Data Center (JMDC) Claims Database.

METHODS

This is a retrospective observational study. Prevalence cases were identified as patients with ≥ 1 inpatient or ≥ 2 outpatient CHB diagnoses and ≥ 2 records for hepatitis B tests or ≥ 1 prescription for CHB treatment between January 2010 and December 2019. Newly diagnosed CHB patients were defined as patients diagnosed from 2010 to 2018 with no history of the disease up to 2 years prior to the diagnosis. The index date is defined as the first CHB diagnosis day. We only used patients' data with ≥ 1-year post-index date.

RESULTS

We identified 13,061 CHB prevalent cases (2010-2019), yielding a crude period prevalence of 0.32%. Newly diagnosed CHB patients (n = 1973; median age 52 years) were followed for a median period of 3.1 years, during which 15% received a CHB treatment. Entecavir was the most common first treatment (66%). During this period, 3.4% of the patients developed compensated cirrhosis (CC), 1.5% decompensated cirrhosis (DC) and 3.0% hepatocellular carcinoma (HCC). Around 43.3% of CHB patients were hospitalized at least once. Hospitalizations, treatment rates, serologic testing and screening for liver diseases increased as the severity of the disease progressed. The average total healthcare cost was 870,568 JPY (7779 USD) per person per year. DC and HCC resulted in the highest management costs.

CONCLUSIONS

Chronic hepatitis B represents a high clinical and economic burden for patients and caregivers, given its morbidity and associated costs.

Prophylactic tenofovir alafenamide for hepatitis B virus reactivation and reactivation-related hepatitis

No prospective study on the efficacy of tenofovir alafenamide (TAF), a novel tenofovir prodrug, in preventing hepatitis B virus (HBV) reactivation has yet been reported. This multicenter prospective study enrolled HBV-carriers who received TAF to prevent HBV reactivation before antitumor or immunosuppressive therapy, and patients with resolved HBV infection who experienced HBV-reactivation and received TAF to prevent HBV reactivation-related hepatitis. The efficacy of prophylactic TAF in preventing HBV reactivation and HBV reactivation-related hepatitis was evaluated at 6 and 12 months after initiating TAF. Overall, 110 patients were administered TAF to prevent HBV reactivation or HBV reactivation-related hepatitis. Three patients died owing to primary disease, whereas one patient was transferred to another hospital within 6 months after initiating TAF. Seven patients died due to primary disease, and five patients were transferred to another hospital within 12 months after initiating TAF. Therefore, 106 and 94 (77 patients with HBV infection, 17 with previous-HBV infection) patients were evaluated at 6 and 12 months after initiating TAF, respectively. No patient experienced HBV reactivation, HBV reactivation-related hepatitis, or treatment discontinuation due to HBV reactivation or adverse events of TAF after 6 and 12 months. TAF could effectively prevent HBV reactivation and HBV reactivation-related hepatitis.

Switching to tenofovir alafenamide versus continued therapy in chronic hepatitis B patients who were treated with entecavir: A prospective, multicenter, randomized controlled study

BACKGROUNDS

Entecavir (ETV) and tenofovir alafenamide fumarate (TAF) have been used widely to treat patients with chronic hepatitis B virus (HBV) infection, but it is still unclear how best to use these drugs. Although some studies compared the efficacies of treatment switch from ETV to TAF, there has been no randomized study.

METHODS

We performed a prospective multicenter randomized controlled study in which subjects were enrolled from April 2018 to June 2019 and observed for 2 years until March 2021 to clarify the efficacy and safety of switching from ETV to TAF.

RESULTS

Thirty-three patients were enrolled and randomized into 2 groups, and a total of 30 patients were evaluated; a TAF-switching group (n = 16) and an ETV-continuing group (n = 14). The mean age of the 30 patients was 61 years old and 18 patients (60%) were male. The serum HBV DNA in all patients were below detection limit. The mean change in hepatitis B surface antigen (HBsAg) levels after 2 years was not significantly different between the TAF and ETV groups (-0.08 vs -0.20 log IU/mL, P = .07). Comparing the group with a HBsAg decline (≤ -0.1 log IU/mL) and a group without a HBsAg decline in an overall analysis, the prior ETV duration was significantly shorter in the HBsAg-declined group (49 vs 92 months, P = .03). Although the eGFR levels tended to decrease in the TAF group compared to ETV (-6.15 vs -2.26 mL/min/1.73 m2, P = .09), no significant differences were observed in patients with baseline eGFR < 60 (-2.49 vs 0.40 mL/min/1.73 m2, P = .25).

CONCLUSION

The efficacy and safety were comparable in the TAF-switching group and the ETV-continuing group. Because the present study was conducted in limited patients, a larger study will be required.

Switching to tenofovir alafenamide for nucleos(t)ide analogue-experienced patients with chronic hepatitis B: week 144 results from a real-world, multi-centre cohort study

BACKGROUND

Tenofovir alafenamide (TAF) may be preferable to other nucleos(t)ide analogues (NA) regarding outcomes against chronic hepatitis B virus (HBV) infection.

AIMS

To evaluate the longer term virological/biochemical effectiveness of TAF and the renal safety of sequential therapy to TAF in real-world settings METHODS: This multi-centre, retrospective cohort study included consecutive adult patients who were switched from other NAs to TAF. We assessed the virological and biochemical responses up to 144 weeks. We performed sensitivity analyses for a subgroup with chronic kidney disease (CKD) at baseline.

RESULTS

We analysed the data of 391 patients with chronic hepatitis B previously treated with entecavir (ETV) (n = 174), tenofovir disoproxil fumarate (TDF) (n = 116) or an NA combination (n = 101) for ≥ 24 months. HBV DNA <10 IU/ml at week 144 was found for 99% of patients, regardless of prior NA regimen or HBV DNA level at baseline. For patients who switched from TDF to TAF, total, low-density lipoprotein, high-density lipoprotein cholesterol and triglycerides were significantly increased after the switch. Patients who switched from a nucleotide analogue to TAF had an improved estimated glomerular filtration rate, although the rate of hypophosphataemia (<2.5 mg/dl) remained 9.7% at week 144. The virological and biochemical responses of patients with CKD were similar to the overall results.

CONCLUSIONS

Switching to TAF remained effective and safe for up to 3 years. Given the increasing comorbidities related to ageing, it will be important to carefully follow the change in the lipid levels of patients with a prior TDF-based regimen.

First-line therapies for hepatitis B in the United States: A 3-year prospective and multicenter real-world study after approval of tenofovir alefenamide

Real-world data are limited on tenofovir alafenamide (TAF). We aimed to study TAF real-world outcomes with other first-line regimens for chronic hepatitis B (CHB). We enrolled patients with CHB from 10 centers retrospectively and followed them for 36 months prospectively. We analyzed switching patterns of antiviral therapy and treatment outcomes of TAF, tenofovir disoproxil fumarate (TDF), and entecavir therapy. For efficacy and safety, we analyzed a subset of patients with complete data at 24 months after switching to TAF or remaining on TDF or entecavir. Among 1037 enrollees, 889 patients were analyzed. The mean age was 52%, and 72% were hepatitis B e antigen-negative. After enrollment, shifts in therapies were mostly in reduced use of TDF from 63% to 30% due to switching to TAF. Clinical parameters were compared at enrollment or initiation to measures at 24 months for patients remaining on TAF (187), TDF (229), or entecavir (181). At 24 months, a significantly higher portion of patients on TAF achieved hepatitis B virus (HBV) DNA ≤ 20 IU/ml (93% vs. 86%; p = 0.012) and normalized alanine aminotransferase (ALT) (66% vs. 56%; p = 0.031) with stable estimated glomerular filtration rates (eGFRs). However, a higher percentage of the patient with eGFR < 60 ml/mi/1.7 m² was observed in the TDF-treated group (9% vs. 4%; p = 0.010). In patients who remained on entecavir or TDF for 24 months, ALT and HBV-DNA results did not differ significantly from baseline. Treatment of CHB in the United States has significantly shifted from TDF to TAF. Our data suggest that switching from TDF or entecavir to TAF may result in increased frequency of ALT normalization and potential clearance of viremia at the 24-month time point.

One-year efficacy of tenofovir alafenamide in patients with chronic hepatitis B: An observational study

Non-inferior antiviral efficacy and better renal safety have been reported in chronic hepatitis B patients with tenofovir alafenamide (TAF) treatment. The experience in real-world clinical practice is limited.We aimed to explore the efficacy after 1-year TAF treatment.A total of 148 patients (42 HBeAg-positive and 106 HBeAg-negative) with TAF treatment ≥1 year were included. Virological suppression (<20 IU/mL or undetectable), HBsAg level, alanine aminotransferase (ALT) normalization (≤36 U/L), and estimated glomerular filtration rate (eGFR) were analyzed at 1 year. Multivariate logistic regression analysis was performed to determine the associated factors for virological suppression and ALT normalization.Virological suppression was achieved in 83% and the 1-year median decline of hepatitis B virus DNA was 5.18 log IU/mL. ALT normalization occurred in 75.7%. HBsAg level decreased at a median of 0.27 log IU/mL with significant difference from baseline (P < .001). Baseline ALT (odds ratio [OR] 1.005, 95% confidence interval [CI] 1.000-1.010, P = .036) and hepatitis B virus DNA (OR 0.222, 95% CI 0.079-0.621, P = .004) were significant factors for 1-year virological suppression. Age (OR 1.064, 95% CI 1.003-1.130, P = .041) was associated with ALT normalization. Significant changes were observed in creatinine (mean increase 0.03 mg/dL, P = .011) and eGFR (mean decrease 2.6 mL/min/1.73 m2, P = .004) after 1-year TAF treatment.One-year TAF treatment came to good virological response, modest ALT normalization rate and significant HBsAg decline. The observation of significant changes in eGFR warranted further studies.

Review article: switching patients with chronic hepatitis B to tenofovir alafenamide-a review of current data

BACKGROUND

The nucleos(t)ide analogues (NAs) entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) are preferred treatment options for patients with chronic hepatitis B infection (CHB). However, resistance to ETV has been reported, especially with prior exposure to other NAs, and long-term TDF treatment has been associated with decline in renal function and loss of bone mineral density in some patients. Consequently, TAF may be preferable to ETV, TDF or other NAs in specific circumstances such as in patients with risk of bone or renal complications, elderly patients or those with previous NA experience.

AIM

To provide a summary of the available efficacy and safety data following switch to TAF from other NAs in patients with CHB in clinical studies and real-world settings.

METHODS

Literature searches were performed on PubMed and abstracts from three major international liver congresses between 2019 and 2021. Studies that included efficacy and/or safety data for patients with CHB switching from any NA to TAF were selected.

RESULTS

Thirty-six papers and abstracts were included in this narrative review. Switching from TDF to TAF maintained or improved virological and biochemical responses with improved bone and renal safety. Switching from ETV or other NAs to TAF maintained or improved virological and biochemical responses and varying results for bone and renal safety.

CONCLUSIONS

Switching to TAF appears to maintain or improve virological, biochemical and bone- and renal-related safety outcomes. These data support the concept of switching to TAF in some patients with CHB based on their individual circumstances.

Superiority of tenofovir alafenamide fumarate over entecavir for serum HBsAg level reduction in patients with chronic HBV infection: A 144-week outcome study after switching of the nucleos(t)ide analog

Background

To evaluate the long-term efficacy of switching of the nucleos(t)ide analog used for treatment from entecavir (ETV) to tenofovir alafenamide fumarate (TAF) in patients with chronic HBV infection.

Methods

A total of 103 patients with serum HBsAg levels of ≥100 IU/mL who had received ETV were enrolled. The nucleos(t)ide analog used for the treatment was switched from ETV to TAF, and the changes in serum HBsAg levels during the 144-week period before and after the drug switching were compared in 74 patients who had received ETV at least for 192 weeks.

Results

Significant decreases of serum HBsAg levels were observed during both the ETV and the TAF administration period, although the degree of reduction was greater during the latter period than during the former period (P<0.001). Significant decreases of serum HBsAg levels were seen in both patients with genotype B HBV infection and genotype C HBV infection, irrespective of the serum HBsAg and HBcrAg levels at the time of the drug switching.

Conclusion

Switching of the nucleos(t)ide analog used for treatment from ETV to TAF merits consideration in patients with chronic HBV infection, since the extent of reduction of the serum HBsAg level was greater during the TAF treatment period than during the ETV treatment period.

Change in tartrate-resistant acid phosphatase isoform 5b levels, a marker of bone metabolism, in patients with chronic hepatitis B treated with tenofovir alafenamide

Hepatitis B virus (HBV) infection is associated with the risk of osteoporosis and bone mineral density (BMD) loss. Tenofovir alafenamide (TAF) is associated with a slightly lower degree of BMD loss compared with tenofovir disoproxil, without loss of the excellent anti-HBV effects. The aim of the present study was to verify the effect of bone metabolism in patients with HBV treated with TAF. A total of 87 patients were treated with TAF. Of these, 32 patients were treatment naïve, and 55 patients were treated with entecavir (ETV) for at least 1 year, after which ETV was switched to TAF. At the start of TAF and after 1 year, BMD in the lumbar and neck of the femur, tartrate-resistant acid phosphatase isoform 5b (TRACP-5b) levels as a marker of bone metabolism and serum inorganic phosphorus (P) were compared to estimate bone metabolism. Serum creatinine (Cr), cystatin C, urine protein and β2 microglobulin levels were evaluated to estimate kidney function. Treatment with TAF for 1 year decreased TRACP-5b levels, particularly in patients with bone disease, except for a minimal significant change (MSC; decrease of 12.4%) in TRACP-5b levels. The change in rate of TRACP-5b levels were positively associated with changes in P, Cr-estimated glomerular filtration rate and TRACP-5b levels at the start of TAF. Logistic regression analysis showed that increased BMD in the lumbar region contributed to the switch from ETV to TAF. TAF induced a decrease in TRACP-5b levels in patients with HBV. Bone disease was a contributing factor for MSC. Since TRACP-5b can be used as a marker of bone metabolism and fractures, TAF may exhibit potential in preventing fractures in patients with HBV.

Impact of switching to tenofovir alafenamide fumarate in patients with entecavir-treated chronic hepatitis B

BACKGROUND AND AIMS

Tenofovir alafenamide (TAF), a new tenofovir prodrug, has been developed to circumvent the less favorable safety profile of tenofovir disoproxil fumarate (TDF). We investigated reductions in hepatitis B surface antigen (HBsAg) levels in patients with HBV infection who received continuous entecavir (ETV) monotherapy or sequential therapy with ETV and TAF.

METHODS

This retrospective cohort study included 286 patients who were divided into two groups: continuous ETV monotherapy (ETV group, n = 168) and sequential therapy with ETV and TAF (ETV-TAF group, n = 108). Factors associated with a 90% reduction in HBsAg levels were analyzed by a Cox proportional hazards model using a time-dependent covariate in both groups.

RESULTS

In the multivariate Cox proportional hazards model, the ETV-TAF group [adjusted hazard ratio (aHR) 2.750; 95% confidence interval (CI), 1.265-3.405; P = 0.0038] and BMI ≤ 25.0 kg/m2 (aHR 0.520, 95% CI, 0.308-0.875; P = 0.0139) demonstrated a 90% reduction in HBsAg levels. HBsAg levels of patients in the TAF phase in the ETV-TAF group showed greater yearly percent reductions than those in the ETV group and those in the ETV phase in the ETV-TAF group (P = 0.0361 and P = 0.0022, respectively, Steel-Dwass test).

CONCLUSION

HBsAg levels decreased more rapidly after patients switched from ETV to TAF. Switching to TAF may be an effective treatment option to reduce HBsAg levels.

Exosomal lncRNA HOTTIP Mediates Antiviral Effect of Tenofovir Alafenamide (TAF) on HBV Infection

INTRODUCTION

Chronic hepatitis B (CHB) virus (HBV) infection has emerged as a global health burden affecting nearly 292 million people. Tenofovir alafenamide (TAF) is an effective treatment for CHB patients. However, the detailed mechanism underlying the antiviral activity of TAF remains unclear.

METHODS

In this study, we investigated the antiviral effect of exosomes derived from the serum of CHB patients treated with TAF (Exo-serum) and TAF-treated macrophages (MP) (Exo-MP(TAF)).

RESULTS

RNAseq analysis was also performed to determine the associated long non-coding RNAs (lncRNAs). The results demonstrated that both Exo-serum and Exo-MP(TAF) could be taken up by HepAD38 cells and exhibited potent antiviral activities, as manifested by significantly downregulating the levels of hepatitis B surface antigen, hepatitis B e antigen, HBV DNA, and covalently closed circular DNA. The antiviral effect of Exo-serum was more potent than those of TAF treatment alone. RNAseq analysis revealed that lncRNA HOTTIP was upregulated significantly in Exo-serum. Further, lncRNA HOTTIP knockdown reversed the antiviral effect of Exo-MP(TAF) on HepAD38 cells, whereas lncRNA HOTTIP knockdown exerted the opposite roles.

DISCUSSION

Taken together, these results suggest that exosomal lncRNA HOTTIP is essential for the antiviral activity of TAF and provide a novel understanding of the exosome-mediated mechanism underlying HBV infection.

Switching from entecavir to tenofovir alafenamide for chronic hepatitis B patients with low-level viraemia

BACKGROUND AND AIMS

About 20% of patients receiving nucleos(t)ide analogues treatment experienced low-level viraemia (LLV), which is associated with progression of liver fibrosis and high risk of hepatocellular carcinoma. We aimed to evaluate the effectiveness and safety of switching from entecavir (ETV) to tenofovir alafenamide fumarate (TAF) in ETV-treated patients with LLV.

METHODS

In this prospective study, ETV-treated patients with LLV, presented to our hospital from December 2018 to October 2019, were enrolled. Switching to TAF or continuing ETV was given. The primary effectiveness endpoint was complete virological response (CVR) at 24 weeks, and the safety endpoint was the first occurrence of any clinical adverse event during the treatment.

RESULTS

Totally, 211 patients were recruited and propensity score matching (PSM) generated 75 patients in either TAF or ETV group. After PSM, baseline characteristics were balanced in two groups. After 24-week treatment, the CVR and ALT normalization in TAF group were 62.7% and 47.6%, which were higher than 9.3% and 10.5% in ETV group (OR 16.4, 95% CI 6.6-40.0, P < .001) respectively. Subgroup analysis showed that switching to TAF achieved favours CVR regardless of the status of sex, age, CHB family history, HBV DNA, HBeAg and cirrhosis, whereas alcohol consumption and diabetes mellitus might compromise the CVR of switching to TAF. Both therapies were well tolerated and had satisfying renal safety.

CONCLUSIONS

For ETV-treated patients with LLV, switching to TAF is safe enough and superior compared with continuing ETV monotherapy regarding both virological and biochemical benefits.

Outcomes of Sequential Therapy With Tenofovir Alafenamide After Long-term Entecavir

INTRODUCTION

Entecavir (ETV) and tenofovir alafenamide (TAF) are both first-line hepatitis B virus (HBV) therapies, but ETV-to-TAF switch outcome data are limited. We aimed to assess outcomes up to 96 weeks after ETV-to-TAF switch.

METHODS

ETV-treated (≥12 months) chronic hepatitis B patients switched to TAF in routine practice at 15 centers (United States, Korea, Japan, and Taiwan) were included. Primary outcome was complete viral suppression (CVS) rate (HBV DNA <20 IU/mL).

RESULTS

We analyzed 425 eligible patients (mean age 60.7 ± 13.2 years, 60% men, 90.8% Asian, 20.7% with diabetes, 27% with hypertension, 14.8% with cirrhosis, 8.3% with hepatocellular carcinoma, and mean ETV duration before switch 6.16 ± 3.17 years). The mean baseline estimated glomerular filtration rate (eGFR) was 89 ± 19 (chronic kidney disease [CKD] stages: 55.6% stage 1, 35.7% stage 2, and 8.8% stages 3-5). CVS rate increased from 91.90% at switch (from 90.46% 24 weeks before switch) to 95.57% and 97.21% at 48 and 96 weeks after (P = 0.03 and 0.02, respectively). Over the 96 weeks after switch, mean HBV DNA (P < 0.001) but not alanine aminotransferase or CKD stage decreased. Between switch and 96-week follow-up, 11% (26/235) of CKD stage 1 patients migrated to stage 2 and 8% (12/151) of stage 2 patients to stages 3-5, whereas 18% (27/151) from stage 2 to 1, and 19% (7/37) from stages 3-5 to 2. On multivariable generalized estimated equation analysis adjusted for age, sex, hypertension, diabetes, and cirrhosis, baseline eGFR, age (P < 0.001), and CKD stages 2 and 3-5 (vs 1) (both P < 0.001) were associated with lower follow-up eGFR.

DISCUSSION

After an average of 6 years on ETV, CVS increased from 91.9% at TAF switch to 97.2% at 96 weeks later.

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.

Sequential therapy from entecavir to tenofovir alafenamide versus continuous entecavir monotherapy for patients with chronic hepatitis B

Background and Aim

Although tenofovir alafenamide (TAF), as well as entecavir (ETV), is widely used as first‐line treatment for patients with chronic hepatitis B, there are only a few studies comparing sequential therapy from ETV to TAF and continuous ETV monotherapy in patients with maintained virologic response to ETV.

Methods

In a retrospective multicenter study, we investigated the efficacy and safety of sequential therapy from ETV to TAF (ETV‐TAF group) and compared them with continuous ETV monotherapy (ETV group), using propensity score matching, in chronic hepatitis B patients.

Results

From 442 patients, we analyzed 142 patients from each group comprising 71 patients matched for several data, including age, HBV genotype, hepatitis B envelope antigen, cirrhosis, alanine aminotransferase, platelet count, prior ETV monotherapy period, and hepatitis B surface antigen (HBsAg) change during prior ETV monotherapy. In the ETV‐TAF group, HBsAg levels significantly decreased from baseline to 48 weeks after switching to TAF (−0.02 log IU/mL, P = 0.038). HBcrAg levels also significantly decreased after switching to TAF (−0.1 log IU/mL, P = 0.004). However, there were no significant differences in the reduction of HBsAg and HBcrAg levels between the ETV‐TAF and ETV groups. There was no significant difference in the change of estimated glomerular filtration rate levels from baseline to 48 weeks between the two groups.

Conclusions

The present study indicated that the efficacy, especially of the HBsAg‐reducing action, and safety of sequential therapy from ETV to TAF were similar to those of continuous ETV monotherapy among chronic hepatitis B patients with maintained virologic response to ETV.

Switching to tenofovir disoproxil fumarate in entecavir-treated chronic hepatitis B patients: A pilot randomized controlled study

Although hepatitis B surface antigen (HBsAg) removal is considered the goal of chronic hepatitis B treatment, it can rarely be achieved with nucleos(t)ide analogues (NAs). It has been reported that tenofovir disoproxil fumarate (TDF) is superior in reducing HBsAg compared with entecavir (ETV) in treatment-naïve patients; however, the effect of TDF in patients who have received NAs is still unclear. The aim of the present study was to evaluate the efficacy of switching from ETV to TDF in patients who were already receiving ETV. A pilot randomized controlled study for 2 years in patients who had been treated with ETV for >1 year and did not exhibit drug resistance was performed (Clinical trial registration: UMIN000021948, UMIN-CTR, May 1, 2016). A total of 20 patients were enrolled and 19 patients were randomized into 2 groups, a TDF-switching group (n=12) or an ETV-continuing group (n=7). The mean change in HBsAg levels after 2 years was greater in the TDF group compared with the ETV group, but the difference was not significant (-0.25 vs. -0.06 log IU/ml). In the TDF group, hepatitis B e antigen (HBeAg)-positive patients at baseline showed significantly greater changes in HBsAg (-0.63 vs. -0.03 log IU/ml; P=0.030). In contrast, no difference between HBeAg-positive and HBeAg-negative patients was observed in the ETV group. No significant differences of estimated glomerular filtration rate and inorganic phosphorus changes were observed among the TDF and ETV groups. In conclusion, a significant HBsAg decrease was not achieved after switching from ETV to TDF in the overall analysis, but HBeAg-positive patients showed a larger HBsAg decrease after switching treatment.

Short-term efficacy after switching from adefovir dipivoxil and tenofovir disoproxil fumarate therapy to tenofovir alaferamide for chronic hepatitis B

The aim of the present study was to evaluate the effects of switching to tenofovir alafenamide (TAF) in patients who had received a nucleos(t)ide analog (NA) for the treatment of chronic hepatitis B (CHB). The data from 33 Japanese patients with CHB who received TAF therapy after using NA [adefovir dipivoxil (ADV) and/or tenofovir disoproxil fumarate (TDF)] were retrospectively analyzed. Specifically, the biochemical and virological markers from the start of the TAF treatment to 6 months later were assessed. Comparative evaluation was performed by dividing patients into two groups: Long-term (n=19) and short-term administration groups (n=14), with a cutoff administration duration of 10 years. In all 33 patients, the levels of serum hepatitis B surface antigen (HBsAg; 1,126±1,724 to 1,001±1,591 IU/ml; P<0.0001), serum alkaline phosphatase (ALP) (320±126 to 283±124 U/l; P=0.028), serum bone specific alkaline phosphatase (19.7±9.0 to 17.7±8.0 µg/l; P=0.0006) and urine β2-microglobulin-creatinine ratio (U-BMG/Cr; 5,224±17,471 to 3,547±14,652 µg/g·Cre; P=0.002) significantly decreased from baseline after 6 months. Serum HBsAg, serum ALP and U-BMG/Cr showed a significant reduction in both groups. In conclusion, switching from ADV or TDF to TAF resulted in a decrease in serum HBsAg and improvement in serum ALP and U-BMG/Cr after 6 months of treatment in patients regardless of history of treatment with NA.

Tenofovir alafenamide after switching from entecavir or nucleos(t)ide combination therapy for patients with chronic hepatitis B

BACKGROUND AND AIMS

Tenofovir alafenamide (TAF) has been newly approved for the treatment of chronic hepatitis B (CHB). We aimed to assess the effectiveness and renal safety of switching from entecavir (ETV) or nucleos(t)ide analogue (NA) combination therapy to TAF.

METHODS

This multicentre, retrospective, cohort study included 313 consecutive CHB patients who switched to TAF monotherapy after treatment with ETV or a nucleos(t)ide analogue (NA) combination for over 2 years. Virological/laboratory responses were evaluated for 48 weeks after switchover. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m² . Differences in longitudinal parameters were compared by the generalized estimating equation method.

RESULTS

In the prior ETV group (n = 191), the HBV DNA suppression rate at week 48 was significantly increased, from 75.9% to 96.9% (P < .001). Additionally, mean changes in the HBsAg level at week 48 in HBsAg ≥ 3.0 logIU/mL and < 3.0 logIU/mL groups were -0.09 and -0.13 logIU/mL respectively. In the prior NA combination group (n = 122), the mean changes in HBsAg level at week 48 in the HBsAg ≥ 3.0 logIU/mL and <3.0 logIU/mL groups were -0.08 and -0.11 logIU/mL respectively. For patients with CKD, the eGFR at week 48 was significantly improved compared to those with non-CKD (adjusted slope coefficient difference: 2.75 mL/min/1.73 m² /48 weeks; P = .001).

CONCLUSIONS

Switching from ETV or an NA combination to TAF was effective for HBV suppression and continued HBsAg reduction. Moreover, the renal glomerular function of patients in the prior NA combination group with CKD was significantly improved compared to those with non-CKD.

LAY SUMMARY

Nucleos(t)ide analogues, such as entecavir, tenofovir disoproxil fumarate and tenofovir alafenamide, inhibit hepatitis B virus (HBV) replication and are recommended as first-line oral agents for chronic HBV infection. We evaluated the virological/biochemical effects and renal safety when patients are switched from entecavir or nucleoside-nucleotide analogue combination therapy to tenofovir alafenamide. Our findings suggest that switching to tenofovir alafenamide was effective for HBV suppression and the improvement in renal function for patients with chronic kidney disease.

An expert review on the use of tenofovir alafenamide for the treatment of chronic hepatitis B virus infection in Asia

Asia has intermediate-to-high prevalence and high morbidity of hepatitis B virus (HBV) infection. The use of guideline-recommended nucleos(t)ide analogs with high barrier to resistance, such as entecavir (ETV), tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide (TAF), is one of the key interventions for curbing HBV infection and associated morbidity in Asia. However, there are some challenges to the use of ETV and TDF; while ETV is associated with high resistance in lamivudine (LAM)-exposed (especially LAM-refractory) patients; bone and renal safety issues are a major concern with TDF. Hence, a panel of twenty-eight expert hepatologists from Asia convened, reviewed the literature, and developed the current expert opinion-based review article for the use of TAF in the resource-constrained settings in Asia. This article provides a comprehensive review of two large, phase 3, double-blind, randomized controlled trials of TAF versus TDF in HBeAg-negative (study 0108) and HBeAg-positive (study 0110) chronic HBV patients (> 70% Asians). These studies revealed as follows: (1) non-inferiority for the proportion of patients who had HBV DNA < 29 IU/mL; (2) significantly high rate of normalization of alanine aminotransferase levels; (3) no incidence of resistance; and (4) significantly better bone and renal safety, with TAF vs. TDF up to 144 weeks. Considering the benefits of TAF, the expert panel proposed recommendations for optimizing the use of TAF in Asia, along with guidance on specific patient groups at risk of renal or bone disease suitable for TAF therapy. The guidance provided in this article may help clinicians optimize the use of TAF in Asia.