Switching from tenofovir disoproxil fumarate to tenofovir alafenamide in virologically suppressed patients with chronic hepatitis B: a randomised, double-blind, phase 3, multicentre non-inferiority study

Switching from tenofovir disoproxil fumarate to tenofovir alafenamide in virologically suppressed patient with chronic hepatitis B

BACKGROUND AND AIM

Our study evaluated the outcomes of switching from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) in patients with chronic hepatitis B (CHB). We assessed viral and biochemical responses as well as changes in the estimated glomerular filtration rate (eGFR) and bone mineral density (BMD).

METHODS

This retrospective multicenter study included CHB patients who achieved virologic response (VR) (HBV DNA < 20 IU/mL) while on TDF and were subsequently switched to TAF between April 2018 and October 2021.

RESULTS

This study included 309 patients with a median age of 59 years, and 42.1% were male. The mean duration of TDF and TAF administration were 54.0 and 37.5 months, respectively. All patients maintained VR after switching to TAF. Alanine aminotransferase (ALT) normalization rate significantly increased 6 months after switching (74.8%-83.5%; P = 0.008). Adjusted eGFR significantly improved at 6 months (+5.55 ± 10.52 mL/min/1.73 m2; P < 0.001) and 12 months (+6.02 ± 10.70 mL/min/1.73 m2; P < 0.001) after switching. In the subgroup of patients with renal impairment (eGFR < 60 mL/min/1.73 m2), significant improvement in renal function was observed at 6 months (+0.6 ± 10.5 mL/min/1.73 m2; P < 0.001) and 12 months (+1.0 ± 10.7 mL/min/1.73 m2; P < 0.001) after switching to TAF. In patients with osteoporosis (n = 182), switching to TAF resulted in significant improvement in spine and hip BMD at 12 months, with increases of 9.7% (95% CI: 7.0-12.5) and 9.4% (95% CI: 7.0-11.8), respectively.

CONCLUSION

In this real-world study, switching to TAF was effective and safe in patients, with notable improvements in ALT levels, renal function, and BMD.

Real-world safety and effectiveness of tenofovir alafenamide for 144 weeks in Japanese patients with chronic hepatitis B

Tenofovir alafenamide (TAF), a prodrug of tenofovir, delivers high levels of active drug to hepatocytes and is given in a lower dose than tenofovir disoproxil fumarate (TDF). TAF reduces viral replication in patients with chronic hepatitis B (CHB) similar to TDF and has shown a lower risk of the renal and bone toxicities associated with TDF use. This post-marketing surveillance study examined the safety and effectiveness of TAF in treatment-naïve and -experienced CHB patients who received TAF for 144 weeks at real-world clinical sites in Japan. Safety assessments included the incidence of adverse drug reactions (ADRs), renal and bone events, and changes in selected laboratory parameters. Effectiveness was based on the proportion of patients with HBV DNA levels below the lower limit of quantitation or <29 IU/mL. This analysis included 580 patients; 18.4% of whom were treatment-naïve. The cumulative incidence of ADRs was 0.21 per 100 person-months, and the incidence of serious ADRs was 0.01 (95% CI, 0.00-0.04) per 100 person-months. There were no ADRs of declines in estimated glomerular filtration rates, renal failure or proximal tubulopathy. The most common ADR was hypophosphataemia in seven (1.2%) patients. Two (0.4%) patients each had decreased blood phosphorus, bone mineral density decreased, dizziness and alopecia. Overall, the proportion of virologically suppressed patients increased from 68.8% at baseline to 97.5% at Week 144. These results confirm the real-world safety and effectiveness of TAF in Japanese patients with CHB and are consistent with the findings of other evaluations of the safety and efficacy of TAF in CHB.

Cost-Utility Analysis of Tenofovir Alafenamide and Entecavir in Chronic Hepatitis B Patients: A Markov Decision Model

From the perspective of health economics, the evaluation of drug-related cost effectiveness and clinical utility is crucial. We conducted a cost-utility analysis of two first-line drugs, tenofovir alafenamide (TAF) and entecavir (ETV), in the treatment of chronic hepatitis B (CHB) patients. We performed inverse probability of treatment weighting (IPTW) to match the independent variables between the two treatment groups. The incremental cost effectiveness ratio (ICER) of the two treatment groups was simulated using a decision tree with the Markov annual-cycle model. A total of 54 patients treated with TAF and 98 with ETV from January 2016 to December 2020 were enrolled. The total medical cost in the TAF group was NT$76,098 less than that in the ETV group, and TAF demonstrated more effectiveness than ETV by 3.19 quality-adjusted life years (QALYs). When the time horizon was set at 30 years, the ICER of the TAF group compared with the ETV group was -NT$23,878 per QALY, suggesting more cost savings for TAF. Additionally, with the application of TAF, over NT$366 million (approximately US$12 million) can be saved annually. TAF demonstrates cheaper medical costs and more favorable clinical QALYs than ETV. To balance health insurance benefits and cost effectiveness, TAF is the optimal treatment for CHB.

Long-Term Outcomes after Switching to Tenofovir Alafenamide in Patients with Chronic Hepatitis B

We sought to determine the long-term outcomes of chronic hepatitis B (CHB) cases switching to tenofovir alafenamide (TAF, n = 104, median age = 63.5 years). Data at switching to TAF (baseline) and those at 1, 2, 3, 4, and 5 years from switching to TAF were compared. At baseline, HB envelop antigen (HBeAg) seropositivity was found in 20 patients (19.2%), and undetectable HBV-DNA in 77 patients (74.0%). Percentage of detectable HBV-DNA significantly reduced at any time point. HB surface antigen (HBsAg) levels significantly reduced at 3, 4, and 5 years. The percentage of HBeAg seropositivity significantly reduced at 5 years. HB core related antigen levels did not significantly change. In patients with baseline HbeAg seropositivity, HbsAg levels significantly reduced at any time point, and a similar trend was found in patients without HBeAg seropositivity. In patients with baseline FIB4 index >1.85, HBsAg levels significantly reduced at 3, 4, and 5 years, and in patients with baseline FIB4 index <1.85, HBsAg levels significantly reduced at any time point. The estimated glomerular filtration rate significantly reduced only at 5 years. The discontinuation rate owing to the side effects of TAF was 0%. In conclusion, switching to TAF therapy in patients with CHB may be effective and safe at least up to 5 years.

Switching Tenofovir Disoproxil Fumarate (TDF) to Tenofovir Alafenamide Fumarate (TAF) in Hepatitis B/HIV Co-Infection: A Feasibility Study

PURPOSE

Tenofovir alafenamide (TAF) delivers the active metabolite more efficiently to target cells compared with tenofovir disoproxil fumarate (TDF). Recent studies suggest that TAF is efficacious in treatment naïve individuals who are co-infected with HBV/HIV and may have superior effects on HBV e antigen (HBeAg) seroconversion in this setting. The primary objective of this study was to explore the feasibility of switching from TDF to TAF in HBV/HIV co-infection.

METHODS

In this single-arm, multicenter, open-label study, we recruited patients (n = 20) who were on stable TDF-based antiviral therapy for at least 12 months. All participants had undetectable HIV RNA and HBV DNA levels at the time of screening and were converted to a TAF-based treatment regimen (TAF + emtricitabine + third agent) for 48 weeks.

FINDINGS

Twenty-seven individuals were invited to take part in the screening process; 3 met the exclusion criteria and a further 4 withdrew consent prior to enrolment. The remaining participants were predominantly male (70%), non-cirrhotic (95%) and of Afro-Caribbean ethnicity (60%). All were co-infected with HIV-1 and established on long-term antiretroviral treatment prior to enrolment (median 6.5 years). No adverse events related to the study drug were observed, and most patients (89.5%) maintained undetectable HIV RNA and HBV DNA throughout the follow-up period.

IMPLICATIONS

Switching from TDF to TAF in HBV/HIV co-infection was safe, well tolerated and maintained virological suppression in most patients. Additional studies are needed to confirm these findings in larger cohorts and explore other endpoints.

Nucleos(t)ide analogs for hepatitis B virus infection differentially regulate the growth factor signaling in hepatocytes

BACKGROUND

Recent clinical studies have suggested that the risk of developing HCC might be lower in patients with chronic hepatitis B receiving tenofovir disoproxil fumarate than in patients receiving entecavir, although there is no difference in biochemical and virological remission between the 2 drugs.

METHODS

The effects of nucleoside analogs (NsAs; lamivudine and entecavir) or nucleotide analogs (NtAs; adefovir disoproxil, tenofovir disoproxil fumarate, and tenofovir alafenamide) on cell growth and the expression of growth signaling molecules in hepatoma cell lines and PXB cells were investigated in vitro. The tumor inhibitory effects of NsAs or NtAs were evaluated using a mouse xenograft model, and protein phosphorylation profiles were investigated. The binding of NsAs or NtAs to the insulin receptor (INSR) was investigated by thermal shift assays.

RESULTS

NtAs, but not NsAs, showed direct growth inhibitory effects on hepatoma cell lines in vitro and a mouse model in vivo. A phosphoprotein array revealed that INSR signaling was impaired and the levels of phosphorylated (p)-INSRβ and downstream molecules phosphorylated (p)-IRS1, p-AKT, p-Gab1, and p-SHP2 were substantially reduced by NtAs. In addition, p-epidermal growth factor receptor and p-AKT levels were substantially reduced by NtAs. Similar findings were also found in PXB cells and nontumor lesions of liver tissues from patients with chronic hepatitis B. Prodrug NtAs, but not their metabolites (adefovir, adefovir monophosphate, adefovir diphosphate, tenofovir, tenofovir monophosphate, and tenofovir diphosphate), had such effects. A thermal shift assay showed the binding of NtAs to INSRβ.

CONCLUSIONS

NtAs (adefovir disoproxil, tenofovir disoproxil fumarate, and tenofovir alafenamide), which are adenine derivative acyclic nucleotide analogs, potentially bind to the ATP-binding site of growth factor receptors and inhibit their autophosphorylation, which might reduce the risk of HCC in patients with chronic hepatitis B.

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.

Efficacy and safety of tenofovir alafenamide in patients with chronic hepatitis B exhibiting suboptimal response to entecavir

BACKGROUND

Entecavir (ETV) is a potent and safe antiviral agent for patients with chronic hepatitis B (CHB); however, some patients may exhibit suboptimal response or resistance to ETV. Tenofovir alafenamide (TAF) is a novel tenofovir prodrug with improved pharmacokinetics and reduced renal and bone toxicity compared with tenofovir disoproxil fumarate.

AIM

To evaluate the efficacy and safety of switching from ETV to TAF in patients with CHB exhibiting suboptimal response to ETV.

METHODS

A total of 60 patients with CHB who had been treated with ETV for at least 12 mo and had persistent or recurrent viremia [Hepatitis B virus (HBV) DNA ≥ 20 IU/mL] or partial virologic response (HBV DNA < 20 IU/mL, but detectable) were enrolled in the study. The patients were randomly assigned to either continue ETV (0.5 mg) daily or switch to TAF (25 mg) daily for 48 wk. The primary endpoint was the proportion of patients who achieved a virologic response (HBV DNA level < 20 IU/mL) at week 48. Secondary endpoints included changes in serum alanine aminotransferase (ALT), hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and anti-HBe levels, and renal and bone safety parameters.

RESULTS

At week 48, the proportion of patients who achieved a virologic response was significantly higher in the TAF group than in the ETV group (93.3% vs 66.7%, P = 0.012). The mean reduction in HBV DNA from baseline was also significantly greater in the TAF group than in the ETV group (-3.8 vs -2.4 Log10 IU/mL, P < 0.001). The rates of ALT normalization, HBeAg loss, HBeAg seroconversion, and HBsAg loss were not found to significantly differ between the two groups. None of the patients developed genotypic resistance to ETV or TAF. Both drugs were well tolerated, with no serious adverse events or discontinuations caused by adverse events. No significant changes were observed in the estimated glomerular filtration rate, serum creatinine level, or urine protein-to-creatinine ratio in either group. The TAF group had a significantly lower decrease in bone mineral density at the lumbar spine and hip than the ETV group (-0.8% vs -2.1%, P = 0.004; -0.6% vs -1.8%, P = 0.007, respectively).

CONCLUSION

Switching from ETV to TAF is effective and safe for patients with CHB exhibiting a suboptimal response to ETV and may prevent further viral resistance and reduce renal and bone toxicity.

Tenofovir disoproxil fumarate versus tenofovir alafenamide on risk of osteoporotic fracture in patients with chronic hepatitis B: A nationwide claims study in South Korea

BACKGROUND

As tenofovir disoproxil fumarate (TDF) requires long-term use, a reduction in bone density should be considered a possibility when treating patients with chronic hepatitis B (CHB) with aging and systemic diseases. Patients treated with tenofovir alafenamide (TAF) have improved bone mineral density loss compared to patients treated with TDF. Although improvements in bone density caused by TAF have been reported, studies on the actual reduction of fractures are insufficient.

AIM

To evaluate the impact of TAF on the risk of osteoporotic fractures in comparison with that of TDF.

METHODS

Using the national claims data of the Health Insurance Review and Assessment Service, we conducted a retrospective cohort study of 32,582 patients with CHB who had been initially treated with TDF or TAF between November 2017 and December 2020. The numbers of patients treated with TDF and TAF were 20,877 and 11,705, respectively. The annual fracture rate per 100 patients in each group was calculated, and the Cox proportional hazard ratio (HR) was analysed after applying inverse probability treatment weights (IPTW) for both groups.

RESULTS

Among 32,582 patients, the average age was 47.8 ± 11.2 years, 64.5% were men, and the follow-up period was 24.4 ± 11.6 months. The incidence of osteoporotic fractures was 0.78 and 0.49 per 100 person-years in the TDF and TAF groups, respectively. After application of IPTW, the HR was 0.68 (95% confidence interval 0.55-0.85, p = 0.001).

CONCLUSION

TAF-treated patients with CHB had a significantly lower risk of osteoporotic fracture than TDF-treated patients.

Are the New Nucleos(t)ide Analogs Better than the Old Nucleos(t)ide Analogs?

In treatment-naïve patients with chronic hepatitis B virus (HBV) infection, entecavir (ETV), tenofovir disoproxil fumarate (TDF), and tenofovir alafenamide have a minimal or no risk of drug-resistance. These 3 nucleos(t)ide analog agents are highly potent inducing high rate of virologic response (reducing serum HBV DNA to levels undetectable by polymerase chain reaction assays) in most treatment-naïve patients. Our randomized trials have demonstrated that monotherapy with TDF can provide a successful virological response in most of the heavily pretreated patients with multidrug resistance to ETV or adefovir.

Personalized Antiviral Drug Selection in Patients With Chronic Hepatitis B Using a Machine Learning Model: A Multinational Study

INTRODUCTION

Tenofovir disoproxil fumarate (TDF) is reportedly superior or at least comparable to entecavir (ETV) for the prevention of hepatocellular carcinoma (HCC) in patients with chronic hepatitis B; however, it has distinct long-term renal and bone toxicities. This study aimed to develop and validate a machine learning model (designated as Prediction of Liver cancer using Artificial intelligence-driven model for Network-antiviral Selection for hepatitis B [PLAN-S]) to predict an individualized risk of HCC during ETV or TDF therapy.

METHODS

This multinational study included 13,970 patients with chronic hepatitis B. The derivation (n = 6,790), Korean validation (n = 4,543), and Hong Kong-Taiwan validation cohorts (n = 2,637) were established. Patients were classified as the TDF-superior group when a PLAN-S-predicted HCC risk under ETV treatment is greater than under TDF treatment, and the others were defined as the TDF-nonsuperior group.

RESULTS

The PLAN-S model was derived using 8 variables and generated a c-index between 0.67 and 0.78 for each cohort. The TDF-superior group included a higher proportion of male patients and patients with cirrhosis than the TDF-nonsuperior group. In the derivation, Korean validation, and Hong Kong-Taiwan validation cohorts, 65.3%, 63.5%, and 76.4% of patients were classified as the TDF-superior group, respectively. In the TDF-superior group of each cohort, TDF was associated with a significantly lower risk of HCC than ETV (hazard ratio = 0.60-0.73, all P < 0.05). In the TDF-nonsuperior group, however, there was no significant difference between the 2 drugs (hazard ratio = 1.16-1.29, all P > 0.1).

DISCUSSION

Considering the individual HCC risk predicted by PLAN-S and the potential TDF-related toxicities, TDF and ETV treatment may be recommended for the TDF-superior and TDF-nonsuperior groups, respectively.

Long-term Treatment With Tenofovir Alafenamide for Chronic Hepatitis B Results in High Rates of Viral Suppression and Favorable Renal and Bone Safety

OBJECTIVES

Results from two Phase 3 studies, through 2 years, in chronic hepatitis B infection (CHB) showed tenofovir alafenamide (TAF) had similar efficacy to tenofovir disoproxil fumarate (TDF) with superior renal and bone safety. Here, we report updated results through 5 years.

METHODS

Patients with HBeAg-negative or -positive CHB with or without compensated cirrhosis were randomized (2:1) to TAF 25 mg or TDF 300 mg once daily in double-blind (DB) fashion for up to 3 years, followed by open-label (OL) TAF up to 8 years. Efficacy (antiviral, biochemical, serologic), resistance (deep sequencing of polymerase/reverse transcriptase and phenotyping), and safety, including renal and bone parameters, were evaluated by pooled analyses.

RESULTS

Of 1298 randomized and treated patients, 866 receiving TAF (DB and OL) and 432 receiving TDF with rollover to OL TAF at year 2 (n = 180; TDF→TAF3y) or year 3 (n = 202; TDF→TAF2y) were included. Fifty (4%) TDF patients who discontinued during DB were excluded. At year 5, 85%, 83%, and 90% achieved HBV DNA < 29 IU/mL (missing = failure) in the TAF, TDF→TAF3y, and TDF→TAF2y groups, respectively; no patient developed TAF or TDF resistance. Median eGFR (by Cockcroft-Gault) declined < 2.5 mL/min, and mean declines of < 1% in hip and spine bone mineral density were seen at year 5 in the TAF group; patients in the TDF→TAF groups had improvements in these parameters at year 5 after switching to OL TAF.

CONCLUSIONS

Long-term TAF treatment resulted in high rates of viral suppression, no resistance, and favorable renal and bone safety.

Broadening access to tenofovir alafenamide for the treatment and prevention of HIV-1 infection

INTRODUCTION

Tenofovir alafenamide (TAF), a prodrug of tenofovir, achieves higher intracellular concentrations of tenofovir-diphosphate and 90% lower plasma concentrations of tenofovir compared to tenofovir disoproxil fumarate (TDF). TAF is associated with improved renal and bone safety outcomes.

AREAS COVERED

We review the efficacy and safety of TAF-containing regimens in adults and pediatrics. We highlight safety data during pregnancy, drug interactions during co-administration with tuberculosis treatment, and critical knowledge gaps to be addressed for the successful implementation of TAF in low- and middle-income countries. We performed a search on MEDLINE PubMed and conference websites for relevant articles published from January 2010 to March 2023.

EXPERT OPINION

Current evidence demonstrates that TAF has similar efficacy and tolerability, superior bone and renal safety, and higher rates of dyslipidemia and weight gain, compared with TDF. However, there are several knowledge gaps, in specific sub-populations, that require action. Emerging data suggests that TAF is safe during pregnancy, although fuller safety data to support TAF use in pregnancy is needed. Similarly, there is a lack of evidence that TAF can be used in combination with rifamycin-based tuberculosis treatment in PWH and TB. Further studies are needed to fill knowledge gaps and support the wider rollout of TAF.

Week 96 Results of Switching from Tenofovir Disoproxil Fumarate-Based Antiretroviral Therapy to Coformulated Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide among HIV/Hepatitis B Virus-Coinfected Patients

Data regarding the durability of tenofovir alafenamide (TAF)-containing antiretroviral therapy (ART) in maintaining hepatitis B virus (HBV) viral suppression among HIV/HBV-coinfected patients are limited. Between February and October 2018, 274 HIV/HBV-coinfected participants who had achieved HIV RNA of <50 copies/mL with tenofovir disoproxil fumarate (TDF)-containing ART and switched to elvitegravir/cobicistat/emtricitabine/TAF were prospectively enrolled. Serial plasma HIV and HBV viral loads, HBV and hepatitis D virus (HDV) serology, renal parameters, metabolic profiles, and bone mineral density (BMD) were assessed through 96 weeks. At baseline and weeks 48, 72, and 96, 5.8%, 5.1%, 5.8%, and 5.1% of the participants had plasma HBV DNA of ≥20 IU/mL, and 0%, 0.7%, 1.5%, and 2.2% had HIV RNA of ≥50 copies/mL, respectively. Hepatitis B surface antigen (HBsAg) loss occurred in 1.5% of 274 participants, and hepatitis B e-antigen (HBeAg) loss or seroconversion occurred in 14.3% of 35 HBeAg-positive participants. Compared with baseline, the median urine protein-to-creatinine ratio (79 versus 63 mg/g, P < 0.001) and β2-microglobulin-to-creatinine ratio (165 versus 83 μg/g, P < 0.001) continued to decrease at week 96. BMD of the spine and hip slightly increased (mean change, +0.9% and +0.5%, respectively). The median triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol and high-density lipoprotein (HDL)-cholesterol increased from baseline to week 96 (116 versus 141, 166 versus 190, 99 versus 117, and 42 versus 47 mg/dL, respectively; all P < 0.001), and most of the increases occurred in the first 48 weeks of the switch. Our study showed that switching from TDF-containing ART to elvitegravir/cobicistat/emtricitabine/TAF maintained HBV and HIV viral suppression through 96 weeks among HIV/HBV-coinfected patients. Proteinuria continued to improve, while fasting lipids increased and BMD stabilized at 96 weeks after the switch. IMPORTANCE Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide as a maintenance therapy showed durable and high rates of viral suppression for HIV/HBV-coinfected patients, with only 5.1% and 2.2% of patients having HBV DNA of ≥20 IU/mL and HIV RNA of ≥50 copies/mL, respectively, at 96 weeks. Our study fills the data gap on the long-term clinical effectiveness of tenofovir alafenamide-containing antiretroviral therapy in people living with HIV who have HBV coinfection.

Inverse Propensity Score-Weighted Analysis of Entecavir and Tenofovir Disoproxil Fumarate in Patients with Chronic Hepatitis B: A Large-Scale Multicenter Study

Tenofovir disoproxil fumarate (TDF) is reportedly superior or at least comparable to entecavir (ETV) in preventing hepatocellular carcinoma (HCC) among chronic hepatitis B (CHB) patients; however, it remains controversial. This study aimed to conduct comprehensive comparisons between the two antivirals. CHB patients initially treated with ETV or TDF between 2012 and 2015 at 20 referral centers in Korea were included. The primary outcome was the cumulative incidence of HCC. The secondary outcomes included death or liver transplantation, liver-related outcome, extrahepatic malignancy, development of cirrhosis, decompensation events, complete virologic response (CVR), seroconversion rate, and safety. Baseline characteristics were balanced using the inverse probability of treatment weighting (IPTW). Overall, 4210 patients were enrolled: 1019 received ETV and 3191 received TDF. During the median follow-ups of 5.6 and 5.5 years, 86 and 232 cases of HCC were confirmed in the ETV and TDF groups, respectively. There was no difference in HCC incidence between the groups both before (p = 0.36) and after IPTW was applied (p = 0.81). Although the incidence of extrahepatic malignancy was significantly higher in the ETV group than in the TDF group before weighting (p = 0.02), no difference was confirmed after IPTW (p = 0.29). The cumulative incidence rates of death or liver transplantation, liver-related outcome, new cirrhosis development, and decompensation events were also comparable in the crude population (p = 0.24-0.91) and in the IPTW-adjusted population (p = 0.39-0.80). Both groups exhibited similar rates of CVR (ETV vs. TDF: 95.1% vs. 95.8%, p = 0.38), and negative conversion of hepatitis B e antigen (41.6% vs. 37.2%, p = 0.09) or surface antigen (2.8% vs. 1.9%, p = 0.10). Compared to the ETV group, more patients in the TDF group changed initial antivirals due to side effects, including decreased kidney function (n = 17), hypophosphatemia (n = 20), and osteoporosis (n = 18). In this large-scale multicenter study, ETV and TDF demonstrated comparable effectiveness across a broad range of outcomes in patients with treatment-naïve CHB during similar follow-up periods.

Tenofovir alafenamide versus entecavir for treating hepatitis B virus-related acute-on-chronic liver failure: real-world study

Background and aims

Real-world data regarding hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) patients receiving tenofovir alafenamide (TAF) as an antiviral drug are limited. Hence, we evaluated the efficacy and kidney safety of TAF among this population.

Methods

A total of 272 HBV-related ACLF patients hospitalized at Xiangya Hospital of Central South University were enrolled in this retrospective research. All patients received antiviral therapy with TAF (n = 100) or ETV (n = 172) and comprehensive medical treatments.

Results

Through 1:1 propensity score matching, 100 patients were finally included in each group. At week 48, the survival rates without transplantation of the TAF group and ETV group were 76.00 and 58.00%, separately (P = 0.007). After 4 weeks of treatment, the TAF treatment group exhibited a significantly decline in HBV DNA viral load (P = 0.029). The mean estimated glomerular filtration rate was apparently improved in the TAF group compared with the ETV group (TAF 5.98 ± 14.46 vs. ETV 1.18 ± 18.07 ml/min/1.73 m²) (P < 0.05). There were 6 patients in TAF group and 21 patients in ETV group with chronic kidney disease (CKD) stage progression ≥ 1. By contrast, the ETV treatment group has a greater risk of renal function progression in CKD 1 stage patients (P < 0.05).

Conclusion

This real-world clinical study showed that TAF is more effective than ETV in reducing viral load and improving survival rate in HBV-ACLF patients and the risk of renal function decline is lower.

Clinical trial registration

https://ClinicalTrials.gov, identifier NCT05453448.

Comparison of kidney function decline between chronic hepatitis B patients with or without antiviral therapy

BACKGROUND AND AIMS

Kidney function can deteriorate in patients with chronic hepatitis B (CHB). We compared the risk of kidney function decline between untreated and treated CHB patients receiving antiviral therapy.

METHODS

This retrospective study included 1061 untreated CHB patients and 366 tenofovir alafenamide (TAF), 190 besifovir dipivoxil maleate (BSV), and 2029 entecavir (ETV) users. The primary outcome was kidney function decline, a ≥ one-stage increase in chronic kidney disease for ≥3 consecutive months.

RESULTS

The incidence and risk of kidney function decline were significantly higher in the 1:1 propensity score matched treated group (588 pairs) than in the untreated (2.7 per 1000 person-years [PYs] vs. 1.3 per 1000 PYs, adjusted hazard ratio [aHR] = 2.29, all p < 0.001). The matched TAF group (222 pairs) showed a similar risk for the primary outcome (aHR = 1.89, p = 0.107) despite a significantly higher incidence thereof, compared to the untreated (3.9 vs. 1.9 per 1000 PYs, p = 0.042). The matched BSV and untreated groups (107 pairs) showed no significant differences in the incidence and risk. However, ETV users (541 pairs) carried a significantly higher outcome incidence and risk than the matched untreated (3.6 vs. 1.1 per 1000 PYs, aHR = 1.05, all p < 0.001). Compared to each matched untreated group, changes in the estimated glomerular filtration rate over time were greater in the ETV group (p = 0.010), despite being similar in the TAF (p = 0.073) and BSV groups (p = 0.926).

CONCLUSIONS

Compared with untreated patients, TAF or BSV users showed similar risk, whereas ETV users showed a higher risk of kidney function decline.

Overview of the development of HBV small molecule inhibitors

Like tuberculosis and Acquired Immune Deficiency Syndrome (AIDS), hepatitis B is a globally recognized major public health threat. Although there are many small-molecule drugs for the treatment of hepatitis B, the approved drugs cannot eradicate the pathogenic culprit covalently closed circular DNA in patients, so the patients need long-term medication to control HBV amplification. Driven by a high unmet medical need, many pharmaceutical companies and research institutions have been engaged in the development of anti-HBV drugs to achieve a functional cure for chronic hepatitis B as soon as possible. This review summarizes the pathogenesis of hepatitis B virus and the research progress in the development of anti-HBV small molecule drugs, and introduces the cccDNA formation and transcription inhibitors and core inhibitors in detail, especially emphasizes the role of chinese herbal medicine in the treatment of chronic hepatitis B. Furthermore, this review proposes three potential strategies for cccDNA eradication in the future. We believe this review will provide meaningful guidance to achieve a functional cure for viral hepatitis B in the future.

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.

Treatment Algorithm for Managing Chronic Hepatitis B Virus Infection in the United States: 2021 Update

BACKGROUND & AIMS

Chronic hepatitis B (CHB) infection remains the most frequent etiology of hepatocellular carcinoma globally as well as a major cause of cirrhosis. Despite vaccination, substantial numbers of persons have already been infected with hepatitis B virus and remain at risk of progressive liver disease.

METHODS

In 2004, a CHB management algorithm was developed by a panel of North American hepatologists, which was subsequently updated in 2006, 2008, and 2015. Since the most recent version, several developments have altered the management of CHB. Tenofovir alafenamide, with a more favorable safety profile than tenofovir disoproxil fumarate, has been introduced as an initial antiviral choice as well as an alternative for long-term therapy. Quantitation of hepatitis B surface antigen is becoming more widely available in clinical practice, with implications for monitoring response to treatment. Additionally, there has been a shift in how the natural history of CHB is perceived, as newer evidence has challenged the concept that during the immunotolerant phase of infection disease progression is not a concern. Finally, recent analyses indicate that in the United States, the average age of patients with CHB has increased, implying that the presence of comorbidities, including metabolic liver disease, increasing use of biologics associated with aging will increasingly affect disease management.

RESULTS

This updated algorithm is intended to serve as a guide to manage CHB while new antiviral strategies are developed.

CONCLUSIONS

Recommendations have been based on evidence from the scientific literature, when possible, as well as clinical experience and consensus expert opinion. Points of continued debate and areas of research need are also described.

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.

HERACLIS-TAF: a multi-centre prospective cohort study on 2-year safety and efficacy of tenofovir alafenamide in patients with chronic hepatitis B with renal and/or bone disorders or risks

BACKGROUND

Tenofovir alafenamide (TAF) has exhibited a favourable safety profile on estimated glomerular filtration (eGFR) and bone mineral density (BMD), but has not been extensively studied in patients with renal impairment and/or BMD disorders.

AIMS

To assess predictors of eGFR changes and other safety and efficacy outcomes during 24-month TAF therapy in patients with chronic hepatitis B with renal and/or BMD disorders/risks.

METHODS

Adult patients who started TAF at 13 clinics throughout Greece were prospectively included. Main exclusion criteria were hepatitis D, active malignancy and bisphosphonates recent use. MDRD formula was used for eGFR estimation.

RESULTS

TAF was initiated in 176 patients (91% switched from another agent). At 12 and 24 months, HBV DNA was undetectable in 97% and 100%, and ALT was normal in 96% and 95% of patients. Median ALT decreased from baseline to month 12/24 (p < 0.001). Mean eGFR decreased from previous treatment initiation to baseline (p < 0.001), increased at 12 months and remained stable at 24 months (p ≤ 0.001). An increase in eGFR of >3 ml/min at 12 month was observed in 50% of patients and was associated mainly with baseline eGFR 30-60 ml/min. In patients with baseline phosphate <2.5 mg/dl, mean serum phosphate increased at month-12/24 (p < 0.001). Median BMD did not change significantly from baseline to 12 months but improved at 24 months (p = 0.001).

CONCLUSIONS

In mostly switched patients with renal and/or BMD disorders/risks, eGFR improved after 12-24 months of TAF treatment, especially in patients with baseline eGFR 30-60 ml/min. TAF may also improve low serum phosphate, BMD and ALT, whereas it maintains or induces virological suppression.

Efficacy and safety of tenofovir alafenamide versus tenofovir disoproxil fumarate in treatment-naïve chronic hepatitis B

BACKGROUND AND AIMS

We used real-world data to evaluate the efficacy and safety of tenofovir alafenamide (TAF) compared with tenofovir disoproxil fumarate (TDF) in treatment-naïve patients with CHB.

METHODS

We analysed 2747 patients with CHB under TAF (n = 502) or TDF (n = 2245) treatments. Virological responses (VR: HBV DNA <15 IU/ml), on-treatment ALT normalization, the incidence of HCC, renal function and lipid profiles were compared between these groups. Propensity score matching of 495 pairs was conducted for these comparisons.

RESULTS

The mean age of the total cohort was 48.6 years and 58.2% of the subjects were male. Cirrhosis had a 33.3% prevalence in the population. VRs at 12, 24 and 36 months were achieved in 70.3%, 81.2% and 83.3% of the TAF and 67.9%, 84.3% and 86.1% in the TDF cases respectively (p > 0.05 for all). Normalized ALT, as determined by local laboratory criteria (<40 U/L), occurred in 79.7%, 90.6% and 86.2% of TAF the group and 78.2%, 85.8% and 85.7% of the TDF group at 12, 24 and 36 months respectively (p > 0.05 for all). The HCC risk did not statistically differ across the entire cohort or in the PS-matched cohort. The TAF group showed a lower median increase in serum creatinine from baseline during the early study period. Compared with the TAF, the TDF group showed significant decreases in total cholesterol, triglyceride and HDL, but not in LDL.

CONCLUSIONS

Real-word data indicate that TAF has comparable efficacies to TDF in terms of VR and ALT normalization, with no higher risk of HCC.

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.

Safety and Effectiveness of Tenofovir Alafenamide in Usual Clinical Practice Confirms Results of Clinical Trials: TARGET-HBV

BACKGROUND

Nucleos(t)ide analogues, with a proven record of safety and efficacy, have been the therapy of choice for over a decade for the treatment of chronic hepatitis B. The approval of tenofovir alafenamide (TAF) in 2016 provided an additional treatment option.

AIMS

The aim of this study was to evaluate the characteristics and clinical outcomes of patients treated with TAF in usual clinical practice.

METHODS

Retrospective data from electronic health records was obtained from those enrolled in TARGET-HBV, a longitudinal observational cohort study of patients with chronic hepatitis B managed according to local practice standards at community and academic medical centers throughout the U.S.

RESULTS

Of 500 patients enrolled, most were male (66%) and of Asian race (66%) with median age of 55 years. Cirrhosis was evident in 15%. Most patients (82%) had switched to TAF after treatment with other antivirals. The perceived safety profile of TAF was cited as the primary reason for changing therapy (32%). TAF was well tolerated and only 4 patients discontinued therapy due to adverse event during a median duration of TAF dosing of 74 weeks. Among those with paired laboratory data 12-18 months after switching to TAF, biochemical response and HBV DNA suppression was maintained. Most patients had normal renal function which was essentially unchanged throughout follow-up.

CONCLUSIONS

TAF is frequently utilized in routine clinical practice due to the perception of its improved safety profile. The current study supports the growing body of evidence regarding the safety and effectiveness of TAF. Trial Registration ClinicalTrials.gov identifier: NCT03692897, https://clinicaltrials.gov/ct2/show/NCT03692897 .

First-In-Human Study on Pharmacokinetics, Safety, and Tolerability of Single and Multiple Escalating Doses of Hepenofovir, a Novel Hepatic Targeting Prodrug of Tenofovir in Healthy Chinese Subjects

Objective: Hepenofovir, a novel hepatic targeting prodrug of tenofovir, has been developed for the treatment of chronic hepatitis B (CHB). This is a first-in-human study to evaluate the pharmacokinetics (PK) and tolerability of single and multiple escalating doses of hepenofovir in healthy Chinese subjects. Methods: This phase Ia study included two parts: a double-blinded, randomized, placebo-controlled single-ascending-dose (SAD) (25-200 mg) study under fasted conditions comprising a food-effect investigation (200 mg) and a multiple-ascending-dose (MAD) (25 mg) study under fasted conditions. Results: Hepenofovir was well tolerated in healthy Chinese subjects. There was no significant difference in adverse reaction rates between hepenofovir and placebo groups. Hepenofovir was rapidly absorbed and metabolized into tenofovir after dosing. In healthy participants, the median Tmax of hepenofovir and tenofovir was 0.33-0.50 h and 0.62-0.75 h, respectively, and their mean half-life was 2.5-12.3 h and 49.7-53.8 h, respectively. Systemic exposure to tenofovir increased in proportion to the dose. The mean accumulation indexes of hepenofovir and tenofovir were 1.1 vs. 1.8. Moreover, food could reduce the Cmax of both hepenofovir and tenofovir, but did not affect their area under the curve (AUC). Conclusions: Hepenofovir has shown a favorable safety and PK profile, which support the further evaluation of its safety and efficacy in CHB patients. Clinical trial registration number: The trial is registered at Chinese Clinical Trial website (http://www.chinadrugtrials.org.cn/index.html # CTR20191953).

Tenofovir alafenamide is associated with improved alanine aminotransferase and renal safety compared to tenofovir disoproxil fumarate

BACKGROUND & AIMS

Tenofovir alafenamide (TAF) is a novel prodrug of tenofovir for the treatment of chronic hepatitis B (CHB) infection. We aimed to evaluate the impact of switching to TAF on alanine aminotransferase (ALT) normalization and renal safety. We also described the indications of switching to TAF.

METHODS

Consecutive adult CHB patients switched from tenofovir disoproxil fumarate (TDF) dominant therapy to TAF for more than 12 months were identified retrospectively. A subgroup of patients newly switched to TAF were prospectively invited to perform transient elastography examination and dual-energy X-ray absorptiometry. The time of switching to TAF was defined as baseline.

RESULTS

Among 393 patients in the retrospective cohort, the median ALT at month 12 was significantly lower (21.0 [16.0 - 29.9] U/L vs. 25.0 [19.0 - 34.0] U/L; P < 0.001) and ALT normalization rate was higher (89.9% vs. 83.7%; P = 0.037) than those at baseline. Estimated glomerular filtration rate decreased from 12 months before baseline and then increased from baseline to month 12 significantly (69.7 ± 22.0 mL/min/1.73m² vs. 68.5 ± 21.5 mL/min/1.73m² vs. 69.2 ± 21.5 mL/min/1.73m² , P = 0.002 (-12m vs. baseline), P = 0.004 (baseline vs. 12m)). In the prospective cohort, 103 patients switched to TAF because of age > 60 years (63.1%), bone diseases (54.4%) and renal alteration (42.7%).

CONCLUSION

TAF is associated with ALT improvement and better renal safety than TDF dominant therapy in CHB patients. Most CHB patients switched to TAF because of advanced age, followed by bone disease and renal alteration. This article is protected by copyright. All rights reserved.

Changes in blood lipids in patients with chronic hepatitis B after 48 weeks of tenofovir alafenamide treatment: A prospective real-world clinical study

Background

Tenofovir alafenamide (TAF) is a new anti-hepatitis B virus nucleotide analogue that can cause dyslipidaemia in AIDS patients, but the effect of TAF on blood lipids in patients with chronic hepatitis B (CHB) is unknown. This study aimed to evaluate the effect of TAF on blood lipid levels in patients with CHB.

Methods

One hundred and twenty-one CHB patients were recruited as TAF group, including 69 treatment-naïve patients and 52 patients with nucleoside/nucleotide analogue experience before TAF treatment. All patients were followed up regularly for 48 weeks. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and triglyceride (TG) levels and the incidence of dyslipidaemia before and after TAF treatment were compared.

Results

After 48 weeks of TAF treatment, the levels of TC, TGs and LDL-C in TAF group were significantly higher than those in control group. In TAF group, the TC and TG levels were significantly higher than that at baseline. Baseline TC and TGs levels had a significant effect on the incidence of abnormal TC and TG levels after 48 weeks treatment. The LDL-C decreased slightly but not significantly. The proportion of patients with TC abnormalities increased from 20.7% at baseline to 26.3% at week 48, LDL-C abnormalities decreased from 50.4% to 42.5% and TG abnormalities increased from 14.2% to 22.5%. There were no significant differences compared with control group, as well as compared with baseline.

Conclusions

Tenofovir alafenamide treatment mainly affects the TC and TG level in patients with CHB but has little effect on LDL-C.

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.

Editorial: does TAF have a better or worse safety profile than TDF, to treat hepatitis B? Authors' reply

This article is linked to Lim et al papers. To view these articles, visit https://doi.org/10.1111/apt.16788 and https://doi.org/10.1111/apt.16854

Tenofovir alafenamide fumarate

Tenofovir alafenamide fumarate is a lipophilic prodrug of tenofovir which is preferentially metabolized in lymphatic tissue resulting in high concentrations of tenofovir (TFV) and its active diphosphate metabolite inside the cells that replicate HIV. Due to its selectivity for these tissues, lower total doses of TAF can be administered relative to tenofovir disoproxil fumarate (TDF) which results in improved bone and renal biomarkers. Tenofovir alafenamide fumarate has become the “backbone” of multiple combination products for the treatment of HIV, combined with emtricitabine for PreP and as a monotherapy for the treatment or HBV.

Safety of current antiviral drugs for chronic hepatitis B

INTRODUCTION

Oral nucleos(t)ide analogues (NUCs) are recommended as first-line therapy for chronic hepatitis B due to higher HBV-DNA suppression rates and safety profile. Long-term treatment with NUCs is often necessary to achieve durable viral suppression.

AREAS COVERED

This review provides an overview of the long-term safety data that have become available since entecavir (ETV) and tenofovir disoproxil fumarate (TDF) were first approved, and recent data on tenofovir alafenamide (TAF) in patients with CHB.

EXPERT OPINION

NUCs generally show remarkable safety in patients taking them for long periods. Nevertheless, renal and bone toxicity may occur in a minority of patients on TDF therapy. These effects have been overcome by the recent release of TAF. Moreover, the currently available data do not allow firm conclusions on superiority of TDF on ETV about HCC risk reduction. Observational studies involving more homogeneous cohorts are therefore needed; furthermore long-term studies assessing impact of TAF on this important topic are warranted.

Comparison of biochemical response during antiviral treatment in patients with chronic hepatitis B infection

BACKGROUND & AIMS

This multicenter cohort study aimed to compare the real-world biochemical response rates during tenofovir alafenamide (TAF), tenofovir disoproxil fumarate (TDF), and entecavir (ETV) treatment in chronic hepatitis B virus (HBV) infection patients.

METHODS

Overall, 1282 treatment-naïve patients with CHB who commenced TAF (n = 270), TDF (n = 617), or ETV (n = 395) were analysed for biochemical response rates during the antiviral treatment using a time-dependent Cox proportional hazard model after the inverse probability of treatment weighting (IPTW).

RESULTS

Patients treated with ETV were older (55.1 ± 11.5 years) than TAF or TDF (P < .0001). ETV was more frequently prescribed to patients with diabetes mellitus (DM, P = .003), hypertension (P < .0001), chronic kidney disease (P < .0001), and negative e-antigen (P < .0001). Cumulative biochemical response rate was independently lower in patients with radiologic fatty liver (HR, 0.75; 95% CI, 0.61-0.94) and obese patients without DM (HR, 0.85; 95% CI, 0.68-0.98) according to multivariable Cox analyses based on time-dependent variables after IPTW for age, sex, liver cirrhosis, baseline e-antigen, ALT, and HBV DNA levels. ETV treated patients (HR, 1.38; 95% CI, 1.13-1.68) showed higher biochemical response rates compared with TAF- or TDF-treated patients after adjusting for similar parameters.

CONCLUSIONS

In real-world practice, ETV was preferable for older, hepatitis B e-antigen negative patients with underlying comorbidities. Biochemical responses in patients treated with ETV, TAF, and TDF were significantly affected by metabolic factors such as fatty liver, obesity, and DM. However, the mechanism behind the higher biochemical response rate in patients treated with ETV should be investigated further.

Renal safety and biochemical changes for 2 years after switching to tenofovir alafenamide from long-term other nucleotide analog treatment in patients with chronic hepatitis B

BACKGROUND

Long-term use of nucleotide analogs such as adefovir (ADV) or tenofovir disoproxil fumarate (TDF) may cause renal impairment. Tenofovir alafenamide (TAF) has less systemic exposure than TDF did. The aims were to examine longitudinal changes in renal function and biochemical parameters for 2 years after switching from long-term ADV and TDF to TAF, and to explore factors associated with improved renal function after TAF in patients with chronic hepatitis B.

METHODS

The prospective observational cohort study included 306 patients with chronic hepatitis B who underwent switching from long-term TDF or ADV to TAF. The primary outcome was the changes in estimated glomerular filtration rate (eGFR) after TAF.

RESULTS

Among 306 patients, 190 (65.3%) and 106 (34.7%) had chronic kidney disease (CKD) stages 1-2 and 3a-4 at baseline. In patients with CKD stages 3a-4, the mean eGFR significantly increased until week 12 and plateaued from week 12 to year 2 (adjusted slope using linear mixed effect models: +9.01 ml/min/1.73 m² /year until week 12; p < 0.001). In contrast, the mean eGFR plateaued from baseline to year 2 in the CKD stages 1-2 subgroup. Multivariate logistic regression showed that baseline CKD stage ≥3a, steeper decline in eGFR 1 year before TAF, and shorter duration of any nucleotide analog use was significantly associated with ≥10% improvement in eGFR in year 1.

CONCLUSIONS

Switching from TDF or ADV to TAF resulted in favorable renal safety for 2 years. In CKD stage 3a-4 subgroup, eGFR after TAF was recovered in the first 12 weeks and subsequently stabilized.

Tenofovir Alafenamide for Drug-Resistant Hepatitis B: A Randomized Trial for Switching From Tenofovir Disoproxil Fumarate

BACKGROUND & AIMS

It remains unknown whether tenofovir alafenamide (TAF) could replace tenofovir disoproxil fumarate (TDF) in patients with drug-resistant hepatitis B virus (HBV).

METHODS

In this multicenter randomized non-inferiority trial, 174 patients with HBV resistant to multiple drugs (lamivudine, entecavir, and/or adefovir) under TDF monotherapy for ≥96 weeks were randomized 1:1 to switch to TAF (n = 87) or continue TDF (n = 87) for 48 weeks. The primary endpoint was proportion of patients with HBV DNA <60 IU/mL at week 48.

RESULTS

At baseline, 84 and 80 patients had HBV DNA <60 IU/mL in the TAF and TDF groups, respectively. At week 48, the proportion of patients with HBV DNA <60 IU/mL was 98.9% (86/87) in TAF group, showing non-inferiority to TDF group (97.7%, 85/87; difference, 1.1%; 95% confidence interval, -2.7% to 5.0%). Changes in median alanine aminotransferase at week 48 from baseline were statistically different between TAF and TDF groups (-3 IU/L vs +2 IU/L; P = .02). TAF group showed a statistically greater increase in bone mineral density at spine (+1.84% vs +0.08%; P = .01) and numerically higher increase in mean estimated glomerular filtration rate (+8.2% vs +4.5%; P = .06) compared with TDF group. Compared with TDF group, TAF group showed significantly greater increases in mean body weight (0.71 vs -0.37 kg; P = .01) and total, low-density lipoprotein, and high-density lipoprotein cholesterol levels (P < .001 for all) at week 48 from baseline.

CONCLUSIONS

TAF could be substituted for TDF in patients with multidrug-resistant HBV for improved bone and renal safety without a loss of efficacy. However, increases in body weight and cholesterol levels with TAF treatment would be a concern. ClinicalTrials.gov no.: NCT03241641.

Non-Inferior Efficacy of Tenofovir Disoproxil to Tenofovir Disoproxil Fumarate in Virologically Suppressed Chronic Hepatitis B Patients

PURPOSE

Tenofovir disoproxil (TD), modified from tenofovir disoproxil fumarate (TDF), was developed as a salt-free formulation, removing fumarate to improve the ease of oral intake by reducing the tablet's size. We evaluated the maintenance of antiviral effects and overall safety profile of TD 245 mg after switching from TDF 300 mg in patients with chronic hepatitis B (CHB).

PATIENTS AND METHODS

CHB patients with HBV-DNA <69 IU/mL after ≥24 weeks of TDF therapy were enrolled. The primary efficacy endpoint was the HBV-DNA suppression rate (HBV-DNA <69 IU/mL) at week 48; We evaluated the non-inferiority (10% margin) of TD to TDF in terms of efficacy. Safety was assessed based on adverse events (AEs), laboratory tests, bone mineral density, and renal function abnormalities.

RESULTS

Overall, 189 subjects were randomized in a 2:1 ratio, and 117 and 66 subjects in the TD and TDF groups, respectively, completed the study. In the per-protocol set, the HBV-DNA suppression rate at week 48 was 99.1% and 100% in the TD and TDF groups, respectively. The lower limit of the 97.5% one-sided confidence interval for the intergroup difference in HBV-DNA suppression rate was -2.8%, which was greater than the prespecified margin of non-inferiority. The changes in creatinine clearance from baseline to week 48 was significantly less in the TD group and in the TDF group; -0.8 ± 9.8 versus -2.4 ± 12.8 mL/min, respectively (P=0.017).

CONCLUSION

TD was non-inferior to TDF for maintaining viral suppression in CHB patients, showing the less decline of renal function.

Tenofovir Alafenamide Attenuates Effects of Diabetes and Body Mass on Serum Alanine Aminotransferase Activities in Patients With Chronic Hepatitis B

Persistent serum alanine aminotransferase (ALT) elevation in nucleotide/nucleoside analogue (NA)-treated patients with chronic hepatitis B (CHB) has been associated with unfavorable long-term outcomes.¹ It has been consistently shown that a higher proportion of patients receiving tenofovir alafenamide (TAF) achieve normal ALT in comparison with recipients of tenofovir disoproxil fumarate,^2-5 the mechanism for which remains unknown.².

Is tenofovir disoproxil fumarate associated with weight loss?

BACKGROUND

Recent clinical trials have shown weight gain associated with newer antiretrovirals. It is unclear how the nucleoside reverse transcriptase inhibitor backbone affects weight. Recent evidence suggests greater weight gain with tenofovir alafenamide (TAF) compared with tenofovir disoproxil fumarate (TDF). However, it is not fully understood whether TDF contributes to weight suppression.

METHODS

A systematic search of PubMed, Embase and clinicaltrials.gov was conducted to identify all randomized control trials comparing TDF/FTC or TDF to control in HIV-negative individuals. The primary endpoint included the number of events of 5% weight loss. Mantel-Haenszel test with random-effects modelling was used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI). Further analyses of gastrointestinal (GI) adverse events were also undertaken.

RESULTS

Seven PrEP trials: PARTNERS, VOICE, TDF-2, Bangkok PrEP, iPrEX, FEM-PrEP and HPTN 084 were included in the analysis of weight loss, with a total sample size of 19 359. One study (HPTN 084) compared TDF/FTC to cabotegravir (CAB). HIV-negative individuals taking TDF were more likely to experience weight loss compared with control [odds ratio (OR) 1.44; 95% CI 1.12-1.85; P = 0.005). Exposure to TDF was also linked to greater odds of vomiting (OR 1.81; 95% CI 1.20-2.73; P < 0.005). There were no increased odds of nausea, diarrhoea or loss of appetite.

CONCLUSION

There is evidence in HIV-negative individuals that TDF may be associated with weight loss. Further research should be carried out in HIV-positive individuals, and clinical trials of TDF/FTC should publish weight data to widen the evidence base.

Clinical management of chronic hepatitis B: A concise overview

Worldwide, over 250 million people are chronically infected with the hepatitis B virus (HBV). Infected patients have an up to 100-fold increased risk for liver-related complications, including cirrhosis, hepatic decompensation and hepatocellular carcinoma. Nonetheless, the majority of the infections remains asymptomatic, stressing the importance of HBV screening and linkage to care. Excellent clinical outcomes are seen during nucleos(t)ide analogue (NA) therapy, which often is continued indefinitively due to a lack of functional cure. Increasing evidence suggests that NA discontinuation following long-term treatment induced viral suppression in patients without a functional cure may be a favourable option. Reliable biomarkers are, however, urgently needed to select the patients that would benefit from NA withdrawal. In addition, renewed and novel approaches to improve screening and linkage to care are other fundamental factors in the optimisation of the clinical management of chronic hepatitis B.

Real-world experience of switching from tenofovir disoproxil fumarate to tenofovir alafenamide in patients with chronic hepatitis B: a retrospective study

Background

Tenofovir alafenamide (TAF) has good viral suppression efficacy and less adverse effect than tenofovir disoproxil fumarate (TDF). Real-world studies on the antiviral efficacy and safety of switching from TDF to TAF in patients with chronic hepatitis B (CHB) are limited.

Methods

This retrospective study included 167 nucleos(t)ide analogue (NA)-naive patients with CHB. All the patients received TDF at least 12 months before switching and TAF at least 12 months after switching at a single medical center. The Friedman test with Dunn–Bonferroni post hoc tests and repeated-measures analysis of variance was used to analyze the effect of complete viral suppression, alanine aminotransferase (ALT) level normalization, renal function changes, body weight, and body mass index in the periods before and after switching.

Results

The mean age and TDF treatment duration were 52 ± 11 years and 2.8 years (interquartile range, 1.51–5.15 years), respectively. The complete viral suppression rate was similar between the time of switching and 48 weeks after switching to TAF (77.8% vs 76%, P = 1.000). The percentage of alanine aminotransferase (ALT) normalization increased from 26.3% at TDF start to 81.4% (P < 0.001) at time of switching and 89.2% at 48 weeks after switching to TAF (P = 0.428). The median estimated glomerular filtration rate decreased from 100.09 mL/min/1.73 m² at TDF start to 91.97 mL/min/1.73 m² (P < 0.001) at the time of switching and stabilized at 48 weeks after switching to TAF (93.47 mL/min/1.73m², P = 1.000). The body weight decreased from 69.2 ± 12.2 kg at TDF start to 67.4 ± 12.1 kg (P < 0.001) at the time of switching to TAF and returned to 68.7 ± 12.7 kg (P < 0.001) 48 weeks thereafter. The body mass index (BMI) decreased from 25 ± 3.3 kg/m² at TDF start to 24.5 ± 3.3 kg/m² (P = 0.002) at the time of switching to TAF and returned to 25.1 ± 3.6 kg/m² (P < 0.001) 48 weeks thereafter.

Conclusions

Our study showed that switching to TAF from TDF had good antiviral effectiveness and stabilized renal function. The body weight and BMI decreased during TDF therapy and regained after switching to TAF.

Longitudinal renal changes in chronic hepatitis B patients treated with entecavir versus TDF: a REAL-B study

BACKGROUND AND AIMS

We aimed to compare the longitudinal changes in estimated glomerular filtration rate (eGFR) in chronic hepatitis B (CHB) patients treated with entecavir (ETV) vs. tenofovir disoproxil fumarate (TDF).

METHODS

This is a retrospective study of 6189 adult treatment-naïve CHB patients initiated therapy with TDF (n = 2482) or ETV (n = 3707) at 25 international centers using multivariable generalized linear modeling (GLM) to determine mean eGFR (mL/min/1.73 m²) and Kaplan-Meier method to estimate incidence of renal impairment (≥ 1 chronic kidney disease [CKD] stage worsening). We also examined above renal changes in matched ETV and TDF patients (via propensity score matching [PSM] on age, sex, diabetes mellitus [DM], hypertension [HTN], cirrhosis, baseline eGFR, and follow-up duration).

RESULTS

In the overall cohort (mean age 49.7 years, 66.2% male), the baseline eGFR was higher for TDF vs. ETV group (75.9 vs. 74.0, p = 0.009). PSM yielded 1871 pairs of ETV or TDF patients with baseline eGFR ≥ 60 and 520 pairs for the eGFR < 60 group. GLM analysis of the overall (unmatched) cohort and PSM cohorts revealed lower adjusted mean eGFRs in TDF (vs. ETV) patients (all p < 0.01) during 10 years of follow-up. Among PSM eGFR ≥ 60 patients, the 5-year cumulative incidences of renal impairment were 42.64% for ETV and 48.03% for TDF (p = 0.0023). In multivariable Cox regression, TDF vs. ETV (adjusted HR 1.26, 95% CI 1.11-1.43) was associated with higher risk of worsening renal function.

CONCLUSION

Over the 10-year study follow-up, compared to ETV, TDF was associated with a lower mean eGFR and higher incidence of renal impairment.

Effect of tenofovir alafenamide vs. tenofovir disoproxil fumarate on hepatocellular carcinoma risk in chronic hepatitis B

It is unclear whether tenofovir disoproxil fumarate (TDF) or tenofovir alafenamide (TAF) is more effective for preventing hepatocellular carcinoma (HCC) development in patients with chronic hepatitis B (CHB). In this study, we compared the effectiveness of these two antiviral agents for preventing HCC. We included treatment-naïve CHB patients undergoing antiviral therapy with TDF only (TDF group) or a TAF-based regimen (TAF group) at three academic teaching hospitals from 2012 to 2019. The TAF group included patients receiving TAF as first-line treatment and patients switching from TDF to TAF. Patients with decompensated cirrhosis or HCC at enrollment were excluded. Cumulative probabilities of HCC were assessed using Kaplan-Meier methodology. In total, 2,117 patients were included: 1,832 in the TDF group and 285 in the TAF group. The annual HCC incidence was not significantly different between TDF and TAF groups: 1.66 vs. 1.19 per 100 person-years [PY], respectively (multivariate analysis: adjusted hazard ratio [HR] 0.774 [reference: TDF group]; p = .438). Male, liver cirrhosis, hepatitis B e antigen negativity, Fibrosis-4 index>3.25 and low albumin were independently associated with a higher risk of HCC. Propensity score-matched and inverse probability of treatment weighting analyses yielded similar results: 1.56 vs. 1.19 per 100 PY, respectively (HR 1.175; p = .708) and 1.66 vs. 1.29 per 100 PY, respectively (HR 0.888; p = .446). The risk of HCC development was not significantly different between TDF and TAF groups of CHB patients. Further studies with a larger sample size and longer follow-up are required to validate our results.