Improvement of bone mineral density and markers of proximal renal tubular function in chronic hepatitis B patients switched from tenofovir disoproxil fumarate to tenofovir alafenamide

Improvement of hepatic fibrosis after tenofovir disoproxil fumarate switching to tenofovir alafenamide for three years

BACKGROUND

Both tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF) are the first-line treatments for chronic hepatitis B (CHB). We have showed switching from TDF to TAF for 96 weeks resulted in further alanine aminotransferase (ALT) improvement, but data remain lacking on the long-term benefits of TDF switching to TAF on hepatic fibrosis.

AIM

To assess the benefits of TDF switching to TAF for 3 years on ALT, aspartate aminotransferase (AST), and hepatic fibrosis improvement in patients with CHB.

METHODS

A single center retrospective study on 53 patients with CHB who were initially treated with TDF, then switched to TAF to determine dynamic patterns of ALT, AST, AST to platelet ratio index (APRI), fibrosis-4 (FIB-4) scores, and shear wave elastography (SWE) reading improvement at switching week 144, and the associated factors.

RESULTS

The mean age was 55 (28-80); 45.3%, males; 15.1%, clinical cirrhosis; mean baseline ALT, 24.8; AST, 25.7 U/L; APRI, 0.37; and FIB-4, 1.66. After 144 weeks TDF switching to TAF, mean ALT and AST were reduced to 19.7 and 21, respectively. From baseline to switching week 144, the rates of ALT and AST < 35 (male)/25 (female) and < 30 (male)/19 (female) were persistently increased; hepatic fibrosis was also improved by APRI < 0.5, from 79.2% to 96.2%; FIB-4 < 1.45, from 52.8% to 58.5%, respectively; mean APRI was reduced to 0.27; FIB-4, to 1.38; and mean SWE reading, from 7.05 to 6.30 kPa after a mean of 109 weeks switching. The renal function was stable and the frequency of patients with glomerular filtration rate > 60 mL/min was increased from 86.5% at baseline to 88.2% at switching week 144.

CONCLUSION

Our data confirmed that switching from TDF to TAF for 3 years results in not only persistent ALT/AST improvement, but also hepatic fibrosis improvement by APRI, FIB-4 scores, as well as SWE reading, the important clinical benefits of long-term hepatitis B virus antiviral treatment with TAF.

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.

Cost-effectiveness of switching from tenofovir disoproxil fumarate to tenofovir alafenamide versus entecavir for chronic hepatitis B patients in Greece

Aim: This study assessed the clinical impact and cost-effectiveness of switching from tenofovir disoproxil fumarate (TDF) to either tenofovir alafenamide (TAF) or entecavir (ETV) in a Greek chronic hepatitis B (CHB) population. Patients & methods: A Markov model from the perspective of a third-party payer in Greece quantified the health and economic benefits of switching from TDF to either TAF or ETV over a lifetime horizon. Results: Over a lifetime, patients who switch from TDF to TAF versus patients who switch from TDF to ETV had an overall lower incidence of compensated cirrhosis (0.4% lower), decompensated cirrhosis (0.04% lower) and hepatocellular carcinoma (0.25% lower). Chronic kidney disease and end-stage renal disease were also lower in patients who switch to TAF; major osteoporotic fractures were similar for both groups. While total costs were higher for switching from TDF to TAF versus TDF to ETV due to the higher cost of TAF, switching from TDF to TAF versus ETV was cost effective with an incremental cost-effectiveness ratio of €17,113 per quality-adjusted life year. Conclusion: Switching from TDF to TAF in patients living with CHB is a cost effective strategy to reduce adverse liver disease outcomes, while improving bone- and renal-related safety outcomes.

Effects of entecavir and tenofovir alafenamide fumarate treatment on renal function in Japanese elderly patients with chronic hepatitis B

AIM

Entecavir (ETV) and tenofovir alafenamide fumarate (TAF) are considered safe nucleoside/nucleotide analogs (NA) for the kidney. This study aimed to investigate the long-term effects of ETV or TAF on renal function in elderly patients with chronic hepatitis B (CHB) in Japan.

METHODS

The study included 246 CHB patients treated with ETV (184 patients) or TAF (62 patients) for at least 2 years. These patients were divided into two groups: those <65 years of age (130 patients) and those ≥65 years of age (116 patients). The effects of the NAs on renal functions were examined by comparing the estimated glomerular filtration rates (eGFR) from baseline to 2 years between the two groups.

RESULTS

The change in eGFR from baseline to 1 or 2 years after treatment was significantly decreased in both groups. However, the amount of change at 1 and 2 years was significantly greater in the group aged ≥65 years than in the group aged <65 years. The amount of change in eGFR from baseline to 1 and 2 years after treatment was significantly greater in the group aged ≥65 years than in the group aged <65 years, regardless of the type of NA, the prior treatment history, cirrhosis/chronic hepatitis, hypertension, dyslipidemia, and diabetes. Additionally, logistic regression analysis showed that age ≥65 years was independently associated with a decreased eGFR after 2 years of NA treatment.

CONCLUSIONS

Long-term administration of NA to CHB patients over 65 years of age should be carefully monitored for renal impairment.

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.

Population Pharmacokinetics of Tenofovir Alafenamide Fumarate and Its Metabolite Tenofovir in Healthy Chinese Volunteers

Tenofovir alafenamide fumarate (TAF) is a first-line drug for treating hepatitis B virus infection. This study aimed to establish the prodrug-metabolite population pharmacokinetic (PK) model for TAF and its metabolite tenofovir (TFV) in healthy Chinese volunteers and evaluate the factors affecting the PK. Using 1043 TAF and 1198 TFV plasma sample concentrations collected from 67 healthy volunteers, a population PK model was developed using the nonlinear mixed-effects model. The 1-compartment model containing 4 transit compartments and the 2-compartment model accurately described the PK of TAF and TFV, respectively. Covariates such as meal state and sex were found to be statistically significant and potentially clinically relevant. Both internal and external validations demonstrated good stability and predictive performance of the connected model. This study elucidated the PK process by which TAF was absorbed, converted, and finally metabolized and eliminated as TFV, and explored the sources of interindividual variability between TAF and TFV.

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.

Past, present, and future of long-term treatment for hepatitis B virus

The estimated world prevalence of hepatitis B virus (HBV) infection is 316 million. HBV infection was identified in 1963 and nowadays is a major cause of cirrhosis and hepatocellular carcinoma (HCC) despite universal vaccination programs, and effective antiviral therapy. Long-term administration of nucleos(t)ide analogues (NA) has been the treatment of choice for chronic hepatitis B during the last decades. The NA has shown a good safety profile and high efficacy in controlling viral replication, improving histology, and decreasing the HCC incidence, decompensation, and mortality. However, the low probability of HBV surface antigen seroclearance made necessary an indefinite treatment. The knowledge, in recent years, about the different phases of the viral cycle, and the new insights into the role of the immune system have yielded an increase in new therapeutic approaches. Consequently, several clinical trials evaluating combinations of new drugs with different mechanisms of action are ongoing with promising results. This integrative literature review aims to assess the knowledge and major advances from the past of hepatitis B, the present of NA treatment and withdrawal, and the future perspectives with combined molecules to achieve a functional cure.

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.

Efficacy and Long-term Safety of Telbivudine Usage During Second or Third Trimester in Hepatitis B Surface Antigen Positive Mothers With High Viral Load: A 10-year Prospective Study

GOALS

The study is to evaluate the efficacy and long-term safety of telbivudine (LdT) usage for hepatitis B surface antigen (HBsAg) positive pregnant women with high viral load.

BACKGROUND

The efficacy and safety of LdT during pregnancy were not assessed from a long-term perspective.

STUDY

HBsAg-positive pregnant women were enrolled and grouped according to antiviral initiation time. Group A (n=100) and group B (n=100) were treated with LdT initiated in the second or third trimester. Group C (n=90) received no antiviral treatment. The efficacy and safety of LdT treatment were compared and infants were followed-up at 1, 5, and 10 years. Denver developmental screening test was conducted at 5 years.

RESULTS

Viral loads before delivery in LdT-treated groups were lower than that in group C and group A was lower than that in group B ( P <0.001). No infants in LdT-treated groups were infected whereas 8.8% (8/90) infants in group C had positive HBsAg (χ 2 =23.20, P <0.001). All LdT-treated mothers were well tolerated and no LdT-related adverse events in infants were reported. Part of the physical growth index of infants was higher than Chinese standard values (SV) and showed significant differences. In groups A and B, the developmental screening test qualified rate of 100% (48/48) and 97.96% (48/49) showed no significant difference compared with 92% in normal Chinese children (χ 2 =5.72, P =0.06).

CONCLUSIONS

Treatment initiated during the second trimester could strengthen the success of mother-to-child transmission blockage. LdT treatment during pregnancy is safe for both mothers and infants in the long term.

Prevalence of renal and bone risk factors among individuals prescribed oral pre-exposure prophylaxis for HIV

Objectives

The only available oral pre-exposure prophylaxis (PrEP) regimens approved in the United States to prevent HIV infection during the period covered by this study were emtricitabine/tenofovir alafenamide (F/TAF) and emtricitabine/tenofovir disoproxil fumarate (F/TDF). Both agents have similar efficacy, however F/TAF exhibits improved bone and renal health safety endpoints over F/TDF. In 2021, the United States Preventive Services Task Force recommended individuals have access to the most medically appropriate PrEP regimen. To understand the impact of these guidelines, the prevalence of risk factors to renal and bone health was evaluated among individuals prescribed oral PrEP.

Methods

This prevalence study utilized the electronic health records of people prescribed oral PrEP between January 1, 2015 and February 29, 2020. Renal and bone risk factors (age, comorbidities, medication, renal function, and body mass index) were identified using International Classification of Diseases (ICD) and National Drug Code (NDC) codes.

Results

Among 40 621 individuals prescribed oral PrEP, 62% had ≥1 renal risk factor and 68% had ≥1 bone risk factor. Comorbidities were the most frequent (37%) class of renal risk factors. Concomitant medications were the most prominent (46%) class of bone-related risk factors.

Conclusions

The high prevalence of risk factors suggests the importance of their consideration when choosing the most appropriate regimen for individuals who may benefit from PrEP.

Effect of pegylated interferon-α2b add-on therapy on renal function in chronic hepatitis B patients: A real-world experience

Background and aim

Controversy remains as to pegylated interferon-α (PEG-IFNα) antiviral therapy to renal function in chronic hepatitis B (CHB) patients. The aim of this study was to evaluate the influence of PEG-IFNα2b (Y shape, 40 kD) add-on treatment for renal function in CHB patients who received entecavir therapy.

Methods

This was a retrospective observational study to investigate factors related to renal function in 114 CHB patients who received PEG-IFNα2b add-on therapy to entecavir for 48 weeks. Changes of blood urea nitrogen (BUN), serum creatinine (sCr), and estimated glomerular filtration rate (eGFR), which was calculated with both Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease (MDRD) formulas, were analyzed by one-way analysis of variance. A linear mixed effects model for repeated measures was used to assess the correlation between baseline information and eGFR changes at 24 and 48 weeks of therapy. The model considered the baseline age, gender, body weight, viral load, hepatitis B surface antigen, BUN, sCr, and treatment strategy as fixed effects and incorporated random effects for individual subjects.

Results

BUN and sCr was decreased, while eGFR was increased at 12 weeks of therapy. Only eGFR maintained at 24 and 48 weeks of therapy. Patients with female gender, age ≥ 40 years, and baseline HBsAg level &lt; 250 IU/mL showed significant improvement of renal function with PEG-IFNα2b add-on therapy. The linear mixed effects model revealed that female gender, baseline sCr, and PEG-IFNα2b add-on were significant positive predictors for eGFR elevation at 24 and 48 weeks of therapy.

Conclusion

In real-world experience, PEG-IFNα2b add-on therapy might be associated with increased eGFR in CHB patients.

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.

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.

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.

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.

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.

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.

Comparison of Tenofovir Alafenamide and Entecavir Therapy in Patients with Chronic Hepatitis B Initially Treated with Tenofovir Disoproxil: A Retrospective Observational Survey

Background: In chronic hepatitis B patients with or exposed to the risk of osteoporosis or renal dysfunction, switching from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide fumarate (TAF) or entecavir (ETV) may be the right choice. Objectives: This study aimed to present real-life data in terms of the efficacy and safety of a TAF/ETV treatment change while receiving TDF. Methods: This retrospective study was conducted on 344 adult patients from 10 centers. The data of patients who had changed to ETV (n = 107) and TAF (n = 237) while receiving TDF were analyzed. The data collected at 0 and 6 months of treatment were analyzed. The virological response was assessed based on undetected hepatitis B virus (HBV) DNA. Serum alanine aminotransferase (ALT) values were used to evaluate the biochemical response. For renal function, serum creatinine and phosphorus, as well as estimated glomerular filtration rate (eGFR), were recorded. Moreover, lumbar spine and hip T-scores along with the serum lipid profile were evaluated. Results: The mean age of patients was 41.14 ± 13.46 years, and 224 (65.1%) of the participants were male. The treatment arms were not significantly different in terms of demographic characteristics, comorbid diseases, infection duration, family history of HBV infection, blood platelet count, serum biomarkers, such as ALT, phosphorus, creatinine, total bilirubin, albumin, lipid profile, and HBV DNA levels at the beginning. No statistically significant difference was found between the proportion of undetectable HBV DNA of the two treatment groups after 6 months (P = 0.221). The ALT normalization in the ETV and TAF groups at the sixth month compared to the baseline levels was not significantly different (P = 0.853, P = 0.330, respectively). There was no statistically significant difference between the two treatment arms regarding changes in eGFR, creatinine, phosphorus, hip, and spine T-scores from baseline to 6 months (P = 0.296, P = 0.78, P = 0.141, P = 0.832, P = 0.947, respectively). In those who switched to TAF or ETV, low-density lipoproteins cholesterol were observed to be significantly higher after 6 months compared to baseline values (P = 0.002, P = 0.049, respectively). The TC increased significantly in the TAF group (P = 0.035). Conclusions: Our study showed that switching to ETV and TAF sustained the viral suppression and biochemical response achieved by TDF therapy. The treatment switch to TAF of ETV can control renal dysfunction and reduce bone mineral density caused by TDF.

Incident bone fracture and mortality in a large HIV cohort outpatient study, 2000-2017, USA

We evaluated the association of bone fracture with mortality among persons with HIV, controlling for sociodemographic, behavioral, and clinical factors. Incident fracture was associated with 48% greater risk of all-cause mortality, underscoring the need for bone mineral density screening and fracture prevention.

PURPOSE/INTRODUCTION

Low bone mineral density (BMD) and fracture are more common among persons with HIV (PWH) than those without HIV infection. We evaluated the association of bone fracture with mortality among PWH, controlling for sociodemographic, behavioral, and clinical factors.

METHODS

We analyzed data from HIV Outpatient Study (HOPS) participants seen at nine US HIV clinics during January 1, 2000, through September 30, 2017. Incident fracture rates and post-fracture mortality were compared across four calendar periods. Cox proportional hazards analyses determined factors associated with all-cause mortality among all participants and those with incident fracture.

RESULTS

Among 6763 HOPS participants, 504 (7.5%) had incident fracture (median age = 47 years) and 719 (10.6%) died. Of fractures, 135 (26.8%) were major osteoporotic (hip/pelvis, wrist, spine, arm/shoulder). During observation, 27 participants with major osteoporotic fractures died (crude mortality 2.97/100 person-years [PY]), and 48 with other site fractures died (crude mortality 2.51/100 PY). Post-fracture, age- and sex-adjusted all-cause mortality rates per 100 PY decreased from 8.5 during 2000-2004 to 1.9 during 2013-2017 (P<0.001 for trend). In multivariable analysis, incident fracture was significantly associated with all-cause mortality (Hazard Ratio 1.48, 95% confidence interval 1.15-1.91). Among 504 participants followed post-fracture, pulmonary, kidney, and cardiovascular disease, hepatitis C virus co-infection, and non-AIDS cancer, remained independently associated with all-cause mortality.

CONCLUSIONS

Incident fracture was associated with 48% greater risk of all-cause mortality among US PWH in care, underscoring the need for BMD screening and fracture prevention. Although fracture rates among PWH increased during follow-up, post-fracture death rates decreased, likely reflecting advances in HIV care.

Treatment and Renal Outcomes Up to 96 Weeks After Tenofovir Alafenamide Switch From Tenofovir Disoproxil Fumarate in Routine Practice

BACKGROUND AND AIMS

Real-world data for treatment effectiveness and renal outcomes in chronic hepatitis B (CHB) patients who were switched to the new and safer prodrug tenofovir alafenamide (TAF) from tenofovir disoproxil fumarate (TDF) are limited. Therefore, we aimed to evaluate treatment and renal outcomes of this population.

APPROACH AND RESULTS

We analyzed 834 patients with CHB previously treated with TDF for ≥12 months who were switched to TAF in routine practice at 13 US and Asian centers for changes in viral (HBV DNA < 20 IU/mL), biochemical (alanine aminotransferase [ALT] < 35/25 U/L for male/female), and complete (viral+biochemical) responses, as well as estimated glomerular filtration rate (eGFR; milliliters per minute per 1.73 square meters) up to 96 weeks after switch. Viral suppression (P < 0.001) and ALT normalization (P = 0.003) rates increased significantly after switch, with a trend for increasing complete response (P_trend = 0.004), while the eGFR trend (P_trend  > 0.44) or mean eGFR (P > 0.83, adjusted for age, sex, baseline eGFR, and diabetes, hypertension, or cirrhosis by generalized linear modeling) remained stable. However, among those with baseline eGFR < 90 (chronic kidney disease [CKD] stage ≥2), mean eGFR decreased significantly while on TDF (P = 0.029) but not after TAF switch (P = 0.90). By week 96, 21% (55/267) of patients with CKD stage 2 at switch improved to stage 1 and 35% (30/85) of CKD stage 3-5 patients improved to stage 2 and 1.2% (1/85) to stage 1.

CONCLUSIONS

Overall, we observed continued improvement in virologic response, ALT normalization, and no significant changes in eGFR following switch to TAF from TDF.

Development, Characterization and In Vivo Pharmacokinetic Assessment of Rectal Suppositories Containing Combination Antiretroviral Drugs for HIV Prevention

Receptive anal intercourse (RAI) contributes significantly to HIV acquisition underscoring the need to develop HIV prevention options for populations engaging in RAI practices. We explored the feasibility of formulating rectal suppositories with potent antiviral drugs for on-demand use. A fixed-dose combination of tenofovir (TFV) and elvitegravir (EVG) (40 mg each) was co-formulated in six different suppository bases (three fat- and three water-soluble). Fat-soluble witepsol H15 and water-soluble polyethylene glycol (PEG) based suppositories demonstrated favorable in vitro release and were advanced to assess in vivo pharmacokinetics following rectal administration in macaques. In vivo drug release profiles were similar for both suppository bases. Median concentrations of TFV and EVG detected in rectal fluids at 2 h were 1- and 2-logs higher than the in vitro IC50, respectively; TFV-diphosphate levels in rectal tissues met or exceeded those associated with high efficacy against rectal simian HIV (SHIV) exposure in macaques. Leveraging on these findings, a PEG-based suppository with a lower dose combination of tenofovir alafenamide (TAF) and EVG (8 mg each) was developed and found to achieve similar rectal drug exposures in macaques. This study establishes the utility of rectal suppositories as a promising on-demand strategy for HIV PrEP and supports their clinical development.

Hypophosphatemia in people with HIV: no benefit when switching from tenofovir disoproxil fumarate to tenfovir alafenamide

Treatment with tenofovir disoproxil fumarate (TDF) has been associated with hypophosphatemia mainly because of injury of the renal proximal tubulus. Studies on the impact of tenfovir alafenamide (TAF) on phosphate homeostasis in people with HIV (PWH) are limited. Prompted by a patient with phosphate wasting under tenofovir but no other evidence for tubular dysfunction, a retrospective cohort analysis with 102 PWH revealed that hypophosphatemia remained largely unchanged after switching from TDF to TAF.

Suboptimal Response to Tenofovir Alafenamide in Two Patients With HBeAg-Positive Hepatitis B: A Case Report

Tenofovir alafenamide (TAF) is one of the most potent first-line nucleot(s)ide analogs for treating chronic hepatitis B virus (HBV) infections. To date, no cases of TAF drug resistance and/or suboptimal response have been reported. To our knowledge, this is the first report of two adult male patients presenting a suboptimal response response to TAF monotherapy. Our study indicates long-term observations and extensive data are needed to further evaluate the efficacy and safety of TAF, and highlights the need for the development of robust novel direct-acting antivirals and immune therapies for HBV.

Tenofovir Alafenamide Fumarate, Tenofovir Disoproxil Fumarate and Entecavir: Which is the Most Effective Drug for Chronic Hepatitis B? A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

The therapeutic effect of tenofovir alafenamide fumarate (TAF), tenofovir disoproxil fumarate (TDF) and entecavir (ETV) on chronic hepatitis B (CHB) patients remains inconsistent. The aim of this study was to explore the differences in virological responses to TAF, TDF and ETV in patients with CHB.

METHODS

Literature searches were conducted of the PubMed, EMBASE, and the Cochrane Library databases to identify randomized controlled trials and observational studies published up to July 21, 2020. Statistical comparisons of virological response between TDF, ETV, and TAF were carried out with pooled odds ratio (OR) values.

RESULTS

The virological response in TDF-treated CHB patients was notably superior to that of the ETV-treated CHB patients after 12-weeks [OR=1.12, 95% confidence interval (CI): 0.89-1.41], 24-weeks (OR=1.33, 95% CI: 1.11-1.61), 48-weeks (OR=1.62, 95% CI: 1.16-2.25), 72-weeks (OR=1.43, 95% CI: 0.78-2.62), and 96-weeks (OR=1.56, 95% CI: 0.87-2.81) treatment. No significant difference was observed for the virological responses in CHB patients after 48-weeks treatment with TAF or TDF. The virological response in TDF+ETV-treated CHB patients was superior to that of TDF-treated CHB patients after 24-weeks, 48-weeks (OR=1.54, 95% CI: 1.17-2.02), 96-weeks, and 144-weeks.

CONCLUSIONS

The virological response in TDF-treated CHB patients was superior to that in ETV-treated CHB patients, but there was no significant difference between TAF and TDF. In addition, the therapeutic effect of TDF+ETV was superior to TDF alone.

Effectiveness and Renal Safety of Tenofovir Alafenamide Fumarate among Chronic Hepatitis B Patients: Real-World Study

Tenofovir alafenamide fumarate (TAF) has high plasma stability resulting in fewer renal adverse events compared to tenofovir disoproxil fumarate (TDF) in chronic hepatitis B (CHB) patients. We aimed to study the effectiveness and renal safety of TAF in a real-world setting, in patients with or without compromised kidney function. CHB patients (Nucleos(t)ide Analogue [NA]-naïve or experienced) who received TAF >1 year from 11 academic institutions as part of the Canadian Hepatitis B Network (CanHepB) were included. Kidney function was measured by estimated glomerular filtration rate (eGFR) as per Cockcroft-Gault. Patients were followed for up to 160 weeks. Of 176 patients receiving TAF, 143 switched from NA (88% TDF), and 33(19%) were NA naïve. Majority of NA-naïve patients (75%) achieved undetectable HBV DNA after one year of TAF treatment. Majority of patients with eGFR <60 mL/min who had renal deterioration during TDF (76%) reversed to eGFR increase after one year of TAF (p=0.009). Among patients with stage 2 chronic kidney disease (CKD) (eGFR 60-89), the estimated eGFR decline during TDF was halted after switching to TAF (p=0.09). NA-experienced patients with abnormal ALT before TAF showed a significant decline after switching to TAF: -0.005 [-0.006 - -0.004] log₁₀ ULN U/L/month, p<0.001). In CHB patients, TAF was safe, well-tolerated and effective in this real-world cohort. Switching to TAF led to improved kidney function, particularly in those with stage 2 CKD, which suggests that the indication for TAF in the guidelines could be extended to patients with an eGFR higher than 60 mL/min.

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.

Two drugs regimens for HIV

PURPOSE OF REVIEW

As the evidence for two-drug regimens (2DR) for HIV treatment accumulates and 2DR start to enter consensus guidelines, this review covers the history, rationale and current evidence for 2DR in first-line and switch settings.

RECENT FINDINGS

Until recently, most evidence for 2DR was for boosted protease inhibitor-based therapies but now we have large, randomized trials to support the use of dolutegravir (DTG)-based 2DR, both for initial therapy and suppressed switch, with high efficacy and no emergent resistance at failure.

SUMMARY

2DR will increasingly form part of the choice we are able to offer people with HIV but we must consider some of the limitations to ensure these regimens are used in the most clinically appropriate manner.

Selected Thoughts on Hydrophobicity in Drug Design

The fundamental aim of drug design in research and development is to invent molecules with selective affinity towards desired disease-associated targets. At the atomic loci of binding surfaces, systematic structural variations can define affinities between drug candidates and biomolecules, and thereby guide the optimization of safety, efficacy and pharmacologic properties. Hydrophobic interaction between biomolecules and drugs is integral to binding affinity and specificity. Examples of antiviral drug discovery are discussed.

Long-term efficacy and safety of nucleos(t)ides analogues in patients with chronic hepatitis B

Nucleos(t)ide analogues with high barrier to resistance are regarded as the principal therapeutic option for chronic hepatitis B (CHB). Treatment with entecavir (ETV), tenofovir disoproxil (TDF) and the later released tenofovir alafenamide (TAF) is highly effective at controlling hepatitis B virus (HBV) infection and, in the vast majority of patients, is well tolerated. No significant differences in viral suppression have been described among the different regimens, although an earlier achievement in biochemical response has been suggested first under TDF and recently under TAF. High barrier to resistance NAs rarely achieve hepatitis B surface antigen sero-clearance, and therefore should be maintained life-long in most cases. This has increased concerns about treatment-related toxicity, especially in patients under TDF with additional risk factors for kidney and bone impairment. TAF has shown a better bone and kidney safety profile than TDF, although it is not yet available worldwide due to its higher cost. Emergence of adverse events should be monitored since treatment-switch to ETV/TAF seems to be effective and safe in HBV mono-infected subjects. Finally, although an effective antiviral treatment leads to a clear improvement in clinical outcome of CHB patients; the risk of developing hepatocellular carcinoma (HCC) is not completely avoided with viral suppression. Whether tenofovir-based regimens provide any additional benefit over ETV in HCC prevention remains unclear and requires further investigation.

Continuing besifovir dipivoxil maleate versus switching from tenofovir disoproxil fumarate for treatment of chronic hepatitis B: Results of 192-week phase 3 trial

Background/Aims

Besifovir dipivoxil maleate (BSV), an acyclic nucleotide phosphonate, shows potent antiviral activity against hepatitis B virus. Our previous 48-week trial revealed that BSV has comparable antiviral efficacy to tenofovir disoproxil fumarate (TDF) and better safety profiles in terms of improved renal and bone safety. This extension study evaluated the prolonged efficacy and safety of BSV in treatment-naive chronic hepatitis B patients.

Methods

Patients continued to participate in an open-label BSV study after an initial 48-week double-blind comparison of BSV and TDF treatment. The antiviral efficacy and drug safety was evaluated up to 192 weeks in two groups: patients continuing BSV treatment (BSV-BSV) and patients switching from TDF to BSV after 48 weeks (TDF-BSV).

Results

Among 197 patients receiving randomized treatments, 170 (86%) entered the open-label phase and 152 (77%) entered the 192-week extension study. Virological response rates over 192 weeks were 92.50% and 93.06% in the BSV-BSV and TDF-BSV groups, respectively (P=0.90). Hepatitis B envelop antigen seroconversion and alanine aminotransferase normalization rates were similar between the groups (P=0.75 and P=0.36, respectively). There were no drug-resistant mutations to BSV. Bone mineral density and renal function were well preserved in the BSV-BSV group, whereas these initially worsened then recovered after switching therapy in the TDF-BSV group.

Conclusions

BSV maintained potent antiviral efficacy after 192 weeks and showed no evidence of drug resistance. BSV was safe, well tolerated, and effective in patients who switched from TDF to BSV. Trial Registration Number: NCT01937806 (date: 10 Sep 2013).

Bone and renal safety profile at 72 weeks after switching to tenofovir alafenamide in chronic hepatitis B patients

Background and Aim

Tenofovir disoproxil fumarate (TDF) has been efficacious in treating chronic hepatitis B (CHB), but long-term use is accompanied by a decline in renal function and bone mineral density (BMD). Tenofovir alefanamide (TAF) is a prodrug of tenofovir, with similar efficacy in CHB but with fewer side effects than TDF. Recent studies on patients who underwent the switch from TDF to TAF have shown improved bone and renal profiles from 24 to 48 weeks of follow-up.

Methods

This study provides follow-up at 72 weeks in a real-world cohort of 61 Asian CHB patients who were switched from TDF to TAF. All patients had been treated with TDF for at least 12 months with hepatitis B virus DNA <21 IU/mL prior to switch.

Results

Improvements in proximal tubular function, measured by urine beta-2-microglobulin to creatinine and retinol-binding protein to creatinine ratios, were sustained at 72 weeks (P < 0.01). Renal function showed decline at 72 weeks compared to baseline (GFR_CG 90.9 vs 96.3 mL/min, P < 0.01). Improvement in hip BMD was sustained at 72 weeks (mean % change of 17.7% from baseline, P < 0.01). However, spine BMD showed discordance, with initial improvement at 24 weeks (3.3% from week 0, P < 0.01) but regression at 72 weeks (-0.6% from week 0, P = NS). Interestingly, there was a slight increase in weight and BMI after 72 weeks (P < 0.01).

Conclusions

CHB patients who switch from long-term TDF to TAF therapy show sustained improvement in proximal tubular function and hip BMD. Weight gain was noted, and long-term studies are needed to evaluate its effect on patient outcomes.

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.

Application of EASL 2017 criteria for switching hepatitis B patients from tenofovir disoproxil to entecavir or tenofovir alafenamide

BACKGROUND

To overcome safety limitations of tenofovir-disoproxil, EASL guidelines proposed switching chronic hepatitis B patients older than 60 years or with bone or renal disease to tenofovir-alafenamide or entecavir.

AIMS

To estimate the number of patients who would benefit from a treatment switch in a real-life setting.

METHODS

Consecutive hepatitis B patients receiving tenofovir-disoproxil before 31 December 2017 were enrolled in a cross-sectional study in two European hospitals. Clinical and virological data were recorded; renal function was assessed by estimated glomerular filtrate rate, serum phosphate and creatinine, proteinuria, and albuminuria; bone involvement by spine and femur DEXA scan.

RESULTS

In total, 565 patients included: 62 (18-91) years, 75% males, 92% Caucasian, 92% HBeAg-negative, 40% cirrhotic. Fifty-five percent of patients fulfilled age criterion (>60 years). Older patients had higher rates of cirrhosis (51% vs 26%, p<0.001), cardiovascular disease, and renal impairment. Thirty-six percent of patients met renal criteria, more commonly NA-experienced individuals (35% vs 21%, p=0.001); 17% had bone disease. Overall, 66% of patients had at least one criterion (71% if NA-experienced), 8% all three criteria, 28% age and renal criteria.

CONCLUSIONS

Approximately two-thirds of patients receiving long-term tenofovir-disoproxil are candidates for an entecavir or tenofovir-alafenamide switch according to EASL recommendations.

Treatment with tenofovir disoproxil fumarate or entecavir in chronic hepatitis B virus-infected patients with renal impairment: results from a 7-year, multicentre retrospective cohort study

BACKGROUND

Limited data exist regarding tenofovir disoproxil fumarate (TDF) safety and effectiveness in chronic hepatitis B virus-infected (CHB) patients with renal impairment (RI).

AIMS

To compare real-world data on renal safety and effectiveness of TDF vs entecavir (ETV) in CHB patients with moderate-to-severe RI.

METHODS

Retrospective, non-interventional, cohort study analysing medical records for TDF/ETV-treated CHB patients (54 European centres). Included patients experienced moderate-to-severe RI (creatinine clearance 20-60 mL/min [Cockcroft-Gault]) either before TDF/ETV initiation ('before' subgroup [baseline = treatment initiation]) or after TDF/ETV initiation ('after' subgroup [baseline = first RI occurrence]). The primary objective was TDF safety, particularly renal-related adverse events of special interest (AESI). TDF and ETV safety and effectiveness were compared and multivariate analyses were performed using inverse probability treatment weighting.

RESULTS

'Before' subgroup included 107 TDF- and 91 ETV-treated patients; 'after' subgroup included 212 TDF- and 77 ETV-treated patients. Mean baseline creatinine clearance was higher for TDF- vs ETV-treated patients (both subgroups). Median follow-up was 3.1 years (both treatments). AESI were more frequent with TDF vs ETV ('before': 18.7% vs 8.8%; 'after': 9.9% vs 3.9%); however, differences were not significant by multivariate analysis. Only TDF-treated patients experienced renal tubular dysfunction (6.5% 'before'; 1.9% 'after') as well as renal adverse events leading to treatment discontinuation (8.4% 'before'; 7.1% 'after'). Effectiveness was similar between treatments.

CONCLUSIONS

Overall safety was similar for TDF vs ETV (both subgroups). Given that renal tubular dysfunction occurred with TDF and not with ETV, renal safety concerns may be greater with TDF in CHB patients with RI.

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.

Bone Mineral Density, Body Composition, and Mineral Homeostasis Over 24 Months in Urban South African Women With HIV Exposed to Antiretroviral Therapy

Human immunodeficiency virus- (HIV-) infection and antiretroviral therapy (ART) exposure are associated with bone loss. African data are limited despite the region's HIV burden. Of 247 ART-naïve, premenopausal, urban, black African women aged 33.9 ± 6.6 years from Soweto, South Africa, measured at baseline, 110 underwent anthropometry, DXA, and blood and urine collections at 12 and 24 months; 39 were HIV-negative (Nref), 28 were people with HIV (PWH) not ART-exposed for the duration of the study (ART-N), and 43 were PWH who were ART-exposed within the first 12 months (ART-Y). At baseline, the ART-Y group had lower BMI and fat mass than the Nref group. Within 12 months of ART initiation, areal bone mineral density (aBMD) had decreased at the lumbar spine and at the whole body less head, despite increased weight, and hip aBMD had not increased in line with the Nref group. There was no evidence of further bone changes between 12 and 24 months. By 24 months, the ART-Y women had gained weight and fat mass, but remained lighter with less fat than the Nref women. ART initiation normalized the low serum albumin of the ART-Y group at baseline, but was associated with elevated bone turnover markers at 12 and 24 months. Vitamin D status and renal phosphate handling were normal. ART-N had similar aBMD and other characteristics to the Nref group throughout, except unlike the Nref group, weight and fat mass did not increase and serum albumin decreased. This study in African women of childbearing age demonstrated that the bone loss that had occurred in these PWH after ART initiation did not continue after 12 months and that bone loss did not occur in ART-unexposed PWH over 2 years. At 24 months, despite gains in weight and fat mass, ART-exposed women remained lighter, with lower aBMD, fat mass, and higher bone turnover than women without HIV. More studies are required to establish if the bone loss and fat gain reverse, stabilize, or continue with further ART exposure, particularly during and after menopause. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Optimal management of chronic hepatitis B patients receiving nucleos(t)ide analogues

Management of chronic hepatitis B (CHB) is still considered a challenge in clinical practice. Patients must be carefully evaluated before starting therapy. This includes virology and laboratory assessments, an estimation of fibrosis by invasive and/or noninvasive methods, and an estimation of the risk of hepatocellular carcinoma (HCC). Nucleos(t)ide analogues (NAs) with a high barrier to resistance (tenofovir disoproxil fumarate [TDF], entecavir [ETV] and tenofovir alafenamide [TAF]) are the most frequently used treatments because of their good long-term efficacy and tolerability. None of these options has been shown to be more effective than the other, but certain factors should be considered when selecting the best therapy for specific populations. Most patients achieve a virological and biochemical response to these agents, with a low rate of emerging resistance during long-term treatment. However, the rate of hepatitis B surface antigen (HBsAg) loss is low and in most cases NAs therapy is lifelong. Safety concerns for long-term NA use have become a priority in the management of CHB, in particular, the risk of impaired kidney function and bone marrow density loss described with TDF regimens. The risk of HCC is not completely eliminated by NAs. Thus, patients at higher risk should be identified and provided with appropriate surveillance.

The effect of tenofovir disoproxil fumarate on bone mineral density: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis (CRD#42017070552) to quantify the impact of oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) on bone mineral density (BMD) and the risk of osteoporosis, low bone mass and fractures, among people taking it as pre-exposure prophylaxis (PrEP), HIV treatment and HBV treatment.

METHODS

We searched MEDLINE and EMBASE for randomized controlled trials published from 1997-2018 reporting BMD, osteoporosis, low bone mass and/or fractures in treatment-naive patients taking compared with not taking TDF for 48 ±4 weeks. We pooled outcomes using DerSimonian random-effects models.

RESULTS

Our search yielded 5,178 abstracts, representing 3,865 articles, with 25 meeting the inclusion criteria. TDF was associated with greater BMD decline when taken as PrEP (lumbar spine: mean difference [MD]=-0.82%, 95% CI=-1.28, -0.37%, I²=38%; total hip: MD=-0.81%, 95% CI=-1.22, -0.40%, I²=48%) and HIV treatment (lumbar spine: MD=-1.62%, 95% CI=-2.30, -0.95%, I²=93%; total hip: MD=-1.75%, 95% CI=-2.08, -1.42%, I²=83%; femoral neck: MD=-1.26%, 95% CI=-2.15, -0.38%, I²=43%) in comparison to those not taking TDF. Eight studies reported on incident osteoporosis or low bone mass, with variable results. Pooled results from five PrEP studies showed that TDF was not associated with increased fractures compared with no PrEP (RR=1.12, 95% CI=0.752, 1.74, I²=26%).

CONCLUSIONS

TDF caused greater decreases in BMD than did comparators when used for all three indications and the magnitude of this decrease was larger for HIV treatment compared with PrEP. Fractures were not increased among PrEP patients. The clinically significant BMD decline caused by TDF and current expansion of PrEP use suggest attention to the adverse bone effects of TDF will increase in importance.

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.

Tenofovir alafenamide for hepatitis B virus infection including switching therapy from tenofovir disoproxil fumarate

BACKGROUND AND AIM

Tenofovir alafenamide (TAF) is a new prodrug of tenofovir, enabling treatment of patients with hepatitis B virus (HBV) infection at a lower dose than tenofovir disoproxil fumarate (TDF), via more efficient delivery of tenofovir to the hepatocytes. We compared the efficacy and safety of TDF and TAF and investigated switching from TDF to TAF therapy.

METHODS

Consent for TDF and TAF therapy was obtained from 117 and 67 patients from August 2014 to January 2018. In total, 45 and 14 patients were administered with TDF and TAF, respectively, as naïve therapy, and 36 patients were switched from TDF to TAF. The antiviral effects and renal function safety were assessed.

RESULTS

At week 48, the antiviral effects on patients receiving TDF and TAF as naïve therapy were similar in terms of reduction of HBV DNA (-5.6 ± 1.8 logIU/ml vs -5.0 ± 1.7 log IU/ml; P = 0.34) and hepatitis B surface antigen (-0.29 ± 0.64 logIU/ml vs -0.15 ± 0.42 logIU/ml; P = 0.71) levels. A significant decrease in the estimated glomerular filtration rate (eGFR) was seen at 48-week TDF treatment (-5.34 ± 7.69 ml/min/1.73 m² ; P < 0.001). Switching from TDF to TAF did not increase the HBV DNA or hepatitis B surface antigen at 24 weeks. Although the eGFR worsened during TDF therapy (-7.32 ± 4.87 ml/min/1.73 m² ), it improved significantly at week 4 (+3.93 ± 6.18 ml/min/1.73 m² ; P = 0.008) and week 24 (+2.89 ± 4.26 ml/min/1.73 m² ; P = 0.020) after switching from TDF to TAF.

CONCLUSION

Tenofovir disoproxil fumarate and TAF showed adequate antiviral effects as naïve therapies. Furthermore, switching from TDF to TAF therapy contributed to the maintenance of the antiviral effect and recovery of renal dysfunction.

Performance of fracture risk assessment tool in HIV-positive male individuals aged ≥45 years on suppressive antiretroviral therapy

INTRODUCTION

An age-specific evaluation and management algorithm for reduced bone mineral density (BMD) is suggested for HIV-positive patients without major risk factors. Whether combination of BMD and the Fracture Risk Assessment Tool (FRAX) may detect more individuals for therapeutic interventions remains unclear. We aimed to determine the prevalence of middle-aged or older HIV-positive males fitting the criteria of therapeutic interventions with different approaches.

METHODS

From July 2016 to February 2018, HIV-positive male patients aged ≥45 years receiving suppressive antiretroviral therapy were recruited in a cross-sectional study, at two designated hospitals for HIV care in northern Taiwan. Patients with malignancy, AIDS, pre-existing bone disease or immobilization were excluded. Information on clinical and demographic characteristics, FRAX questionnaire, activity questionnaire, BMD and serum 25(OH)D was obtained. FRAX scores combined with BMD (FRAX/BMD) and without BMD (FRAX) were calculated. The data were analysed on the basis of major risk factors for fragility fracture and age stratification, FRAX score and BMD results respectively.

RESULTS

We enrolled 330 patients with a mean age of 51.6 years and CD4 610 cells/μL, in whom 98.1% (n = 324) underwent BMD assessment of one site or more. By FRAX, 6.7% (n = 22) reached treatment thresholds (10-year risk of major osteoporotic fracture ≥20% and/or hip fracture ≥3%). The prevalence of osteopenia (-2.5

CONCLUSIONS

With FRAX as a screening approach among HIV-positive male patients aged ≥45 years, addition of BMD assessment may detect more candidates for therapeutic management.

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Key Words

• ageing
• bone mineral density
• combination antiretroviral therapy
• osteopenia
• osteoporosis

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MESH Headings

• Adult
• Algorithms
• Anti-HIV Agents/therapeutic use
• Bone Density
• Cross-Sectional Studies
• Fractures, Bone/etiology
• HIV Seropositivity/complications
• HIV Seropositivity/drug therapy
• HIV Seropositivity/epidemiology
• Hip Fractures/etiology
• Humans
• Male
• Middle Aged
• Osteoporosis/etiology
• Osteoporotic Fractures/etiology
• Prevalence
• Risk Factors
• Surveys and Questionnaires
• Taiwan/epidemiology

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Affiliation(s)

Mao‐Song Tsai Department of Internal MedicineFar Eastern Memorial HospitalNew Taipei CityTaiwan School of MedicineCollege of MedicineFu Jen Catholic UniversityNew Taipei CityTaiwan
Jun‐Yu Zhang Center of Infection ControlNational Taiwan University HospitalTaipeiTaiwan
Hsin‐Yun Sun Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan
Wen‐Chun Liu Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan
Pei‐Ying Wu Center of Infection ControlNational Taiwan University HospitalTaipeiTaiwan
Chia‐Jui Yang Department of Internal MedicineFar Eastern Memorial HospitalNew Taipei CityTaiwan School of MedicineNational Yang‐Ming UniversityTaipeiTaiwan
Chien‐Ching Hung Department of Internal MedicineNational Taiwan University Hospital and NationalTaiwan University College of MedicineTaipeiTaiwan Department of Tropical Medicine and ParasitologyNational Taiwan University College of MedicineTaipeiTaiwan

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