A Phase 1 Clinical Trial to Assess the Safety and Pharmacokinetics of a Tenofovir Alafenamide/Elvitegravir Insert Administered Rectally for HIV Prevention.

BACKGROUND: On-demand topical products could be an important tool for HIV prevention. We evaluated the safety, pharmacokinetics, and ex vivo pharmacodynamics of a tenofovir alafenamide/elvitegravir (TAF/EVG; 16 mg/20 mg) insert administered rectally. METHODS: MTN-039 was a Phase 1, open-label, single-arm, 2-dose study. Blood, rectal fluid (RF), and rectal tissue (RT) were collected over 72 hours (hr) following rectal administration of one and two TAF/EVG inserts for each participant. ClinicalTrials.gov Identifier: NCT04047420. RESULTS: TAF/EVG inserts were safe and well tolerated. EVG and tenofovir (TFV) were detected in blood plasma at low concentrations: median peak concentrations after 2 inserts were EVG 2.4 ng/mL and TFV 4.4 ng/mL. RT EVG peaked at 2-hr (median 2 inserts= 9 ng/mg) but declined to BLQ in the majority of samples at 24-hr, whereas TFV-DP remained high >2,000 fmol/million cells for 72-hr with 2 inserts. Compared to baseline, median cumulative log10 HIV p24 antigen of ex vivo rectal tissue HIV infection was reduced at each timepoint for both 1 and 2 inserts (p<0.065 and p<0.039, respectively). DISCUSSION: Rectal administration of TAF/EVG inserts achieved high rectal tissue concentrations of EVG and TFV-DP with low systemic drug exposure and demonstrable ex vivo inhibition of HIV infection for 72 hours.

Extended Postexposure Protection Against Vaginal Simian/Human Immunodeficiency Virus Infection With Tenofovir Alafenamide Fumarate/Elvitegravir Inserts in Macaques.

Vaginal inserts that can be used on demand before or after sex may be a desirable human immunodeficiency virus (HIV) prevention option for women. We recently showed that inserts containing tenofovir alafenamide fumarate (TAF, 20 mg) and elvitegravir (EVG, 16 mg) were highly protective against repeated simian/human immunodeficiency virus (SHIV) vaginal exposures when administered to macaques 4 hours before or after virus exposure (93% and 100%, respectively). Here, we show in the same macaque model that insert application 8 hours or 24 hours after exposure maintains high efficacy (94.4% and 77.2%, respectively). These data extend the protective window by TAF/EVG inserts and inform their clinical development for on-demand prophylaxis in women.

Weight, anthropometric and metabolic changes after discontinuing antiretroviral therapy containing tenofovir alafenamide (TAF) in people with HIV.

BACKGROUND: Antiretroviral therapy (ART)-related weight gain is of particular concern in people with HIV (PWH). While weight gain was observed among PWH receiving tenofovir alafenamide (TAF), little is known about the potential reversibility after TAF discontinuation. We evaluated weight and metabolic changes 12 months after TAF discontinuation in the Swiss HIV Cohort Study. METHODS: We included participants who received at least six months of TAF-containing ART between January 2016 and March 2023. Using multivariable mixed-effect models, changes in weight and lipid levels were compared between individuals who continued TAF and those who switched to one of the following TAF-free regimens: TDF-based ART, dolutegravir/lamivudine (DTG/3TC), or long-acting cabotegravir/rilpivirine (CAB/RPV). RESULTS: Of 6555 participants (median age 54 years, 24.3% female, 13% Black), 5485 (83.7%) continued and 1070 (16.3%) stopped TAF. Overall, discontinuing TAF was associated with an adjusted mean weight change of -0.54 kg (95% CI -0.98 to -0.11) after 12 months. In stratified analyses, switching from TAF to TDF led to an adjusted mean weight decrease of -1.84 kg (CI -2.72 to -0.97), and to a decrease in mean total cholesterol (-0.44 mmol/L) and triglycerides (-0.38 mmol/L) after 12 months. Switching from TAF-based ART to DTG/3TC (-0.17 kg, CI -0.82 to 0.48) or long-acting CAB/RPV (-0.64 kg, CI -2.16 to 0.89) did not lead to reductions in weight. CONCLUSIONS: Replacing TAF with TDF in PWH led to a decrease in body weight and an improved lipid profile within one year. Weight changes were not observed among individuals who switched to DTG/3TC or long-acting CAB/RPV.

Tenofovir-Diphosphate and Emtricitabine-Triphosphate Adherence Benchmarks in Dried Blood Spots for Persons with HIV Receiving Tenofovir Alafenamide and Emtricitabine-based Antiretroviral Therapy (QUANTI-TAF).

BACKGROUND: QUANTI-TAF aimed to establish tenofovir-diphosphate/emtricitabine-triphosphate (TFV-DP/FTC-TP) adherence benchmarks in dried blood spots (DBS) for persons with HIV (PWH) receiving tenofovir alafenamide/emtricitabine (TAF/FTC)-based antiretroviral therapy (ART). METHODS: During a 16-week pharmacokinetic study, PWH received TAF/FTC-based ART co-encapsulated with an ingestible sensor to directly measure cumulative (enrollment to final visit) and 10-day adherence. At monthly visits, intraerythrocytic concentrations of TAF/FTC anabolites (TFV-DP/FTC-TP) in DBS were quantified by LC-MS/MS and summarized at steady-state (week 12 or 16) as median (IQR). Linear mixed-effects models evaluated factors associated with TFV-DP/FTC-TP. RESULTS: 84 participants (86% male, 11% female, and 4% transgender), predominantly receiving bictegravir/TAF/FTC (73%) enrolled. 92% completed week 12 or 16 (94% receiving unboosted ART). TFV-DP for <85% (7/72), ≥85%-<95% (9/72), and ≥95% (56/72) cumulative adherence was 2696 (2039-4108), 3117 (2332-3339), and 3344 (2605-4293) fmol/punches. All participants with ≥85% cumulative adherence had TFV-DP ≥1800 fmol/punches. Adjusting for cumulative adherence, TFV-DP was higher with boosted ART, lower BMI, and in non-Blacks. FTC-TP for <85% (14/77), ≥85%-<95% (6/77), and ≥95% (57/77) 10-day adherence was 3.52 (2.64-4.48), 4.58 (4.39-5.06), and 4.96 (4.21-6.26) pmol/punches. All participants with ≥85% 10-day adherence had FTC-TP ≥2.5 pmol/punches. Low-level viremia (HIV-1 RNA ≥20-<200 copies/mL) occurred at 60/335 (18%) visits in 33/84 (39%) participants (range: 20-149 copies/mL), with similar TFV-DP (3177 [2494-4149] fmol/punches) compared with HIV-1 RNA <20 copies/mL visits (3279 [2580-4407] fmol/punches). CONCLUSIONS: We propose PK-based TFV-DP (≥1800 fmol/punches)/FTC-TP (≥2.5 pmol/punches) benchmarks in DBS for PWH receiving unboosted TAF/FTC-based ART with ≥85% adherence. In the setting of high adherence, low-level viremia was common.

Effect of Two Forms of Tenofovir on Duodenal Enterocytes - a Hypothesis for Different Effect of TDF and TAF on Body Weight and Plasma Lipids.

BACKGROUND: Tenofovir disoproxil fumarate (TDF) compared to tenofovir alafenamide (TAF) leads to lower body weight and plasma lipids by an unknown mechanism. We hypothesize that TDF, when absorbed, may damage enterocytes of the proximal duodenum, leading to reduced absorption of nutrients. METHODS: People living with HIV, without significant gastrointestinal symptoms, receiving TDF (n=12) or TAF (n=12) containing regimen underwent esophagogastroduodenoscopies with duodenal biopsies. Plasma/serum concentrations of nutrients absorbed from proximal duodenum and serum intestinal fatty-acid-binding protein (I-FABP), a marker of enterocyte damage, were measured. COX/SDH histochemical staining and electron microscopy (EM) were conducted to evaluate mitochondria. RESULTS: Five patients in TDF (celiac disease (excluded from further analyses), helicobacter gastritis, and three esophagitis) and two in TAF group (two esophagitis) had a pathological finding in esophagogastroduodenoscopy. Villi were flatter (337 (59) vs. 397 (42) µm, p=0.016), crypts non-significantly deeper (200 (46) vs. 176 (27) µm, p=0.2), and villus to crypt ratio lower (1.5 (0.42) vs. 2.5 (0.51), p=0.009) in TDF vs. TAF group. I-FABP concentration was higher in TDF vs. TAF group (3.0 (1.07) vs. 1.8 (0.53) ng/ml, p=0.003). TDF group had numerically but not statistically significantly lower concentrations of folate, vitamins A, B1, D, and E. COX/SDH staining showed signs of mitochondrial damage in 10 participants in TDF and 11 in TAF group. EM studies showed similar mitochondrial damage in both groups. CONCLUSIONS: Duodenal villous alterations may explain TDF-associated decrease in body weight and plasma lipids. Larger studies are needed to evaluate concentrations of nutrients absorbed from duodenum among TDF users.

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.

Metabolic effects and cardiovascular disease risks of antiviral treatments in patients with chronic hepatitis B.

Different antiviral treatments for chronic hepatitis B (CHB) have been known to have different metabolic effects. This study aimed to reveal whether tenofovir alafenamide (TAF)-induced dyslipidemia and its associated outcomes are significant. This study utilized 15-year historical cohort including patients with CHB in Korea and consisted of two parts: the single-antiviral and switch-antiviral cohorts. In the single-antiviral cohort, patients were divided into four groups (entecavir [ETV]-only, tenofovir disoproxil fumarate [TDF]-only, TAF-only, and non-antiviral). Propensity score matching (PSM) and linear regression model were sequentially applied to compare metabolic profiles and estimated atherosclerotic cardiovascular disease (ASCVD) risks longitudinally. In the switch-antiviral cohort, pairwise analyses were conducted in patients who switched NAs to TAF or from TAF. In the single-antiviral cohort, body weight and statin use showed significant differences between groups before PSM, but well-balanced after PSM. Changes in total cholesterol were significantly different between groups (-2.57 mg/dL/year in the TDF-only group and +2.88 mg/dL/year in the TAF-only group; p = 0.002 and p = 0.02, respectively). In the TDF-only group, HDL cholesterol decreased as well (-0.55 mg/dL/year; p < 0.001). The TAF-only group had the greatest increase in ASCVD risk, followed by the TDF-only group and the non-antiviral group. In the switch-antiviral cohort, patients who switched from TDF to TAF had a higher total cholesterol after switching (+9.4 mg/dL/year) than before switching (-1.0 mg/dL/year; p = 0.047). Sensitivity analysis on data with an observation period set to a maximum of 3 years for NA treatment showed consistent results on total cholesterol (-2.96 mg/dL/year in the TDF-only group and +3.09 mg/dL/year in the TAF-only group; p = 0.001 and p = 0.005, respectively). Another sensitivity analysis conducted on statin-treated patients revealed no significant change in cholesterol and ASCVD risk. TAF was associated with increased total cholesterol, whereas TDF was associated with decreased total and HDL cholesterol. Both TAF and TDF were associated with increased ASCVD risks, and statin use might mitigate these risks.

Hepatitis B relapse after entecavir or tenofovir alafenamide cessation under anti-viral prophylaxis for cancer chemotherapy.

BACKGROUND: No study has comparing hepatitis B virus (HBV) relapse rates among patients with both cancer and hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) who completed anti-viral prophylaxis for chemotherapy and then stopped taking entecavir or tenofovir alafenamide (TAF). METHODS: A total of 227 HBeAg-negative cancer patients without cirrhosis who previously took entecavir (n = 144) or TAF (n = 83) for antiviral prophylaxis were enrolled. RESULTS: The cumulative incidence of virological and clinical relapse at 2 years was 37% and 10.4%, respectively, in the entecavir group, and 46.7% and 19.5%, respectively, in the TAF group. The multivariate analysis revealed that the use of hematologic malignancy, TAF use, and high-viremia group at baseline were independent risk factors for virological relapse, and use of rituximab, TAF use, higher FIB-4 index and high-viremia group at baseline were independent risk factors for clinical relapse. After propensity score-matching, the patients who discontinued TAF therapy still exhibited higher virological (P = 0.031) and clinical relapse rates (P = 0.012) than did those who discontinued entecavir therapy. The patients were allocated to high- (> 2000 IU/mL), moderate- (between 20 and 2000 IU/mL) and low- (< 20 IU/mL) viremia groups. In the high-viremia group, those who had taken TAF for antiviral prophylaxis had higher rates of virological and clinical relapse than did those who had taken entecavir; in the moderate- and low-viremia groups, no significant difference in virological and clinical relapse rates was detected between the entecavir and TAF groups. Three patients experienced hepatic decompensation upon clinical relapse. All three patients were lymphoma and underwent rituximab therapy. One patient developed acute on chronic liver failure and died even though timely retreatment. CONCLUSIONS: In patients with both cancer and CHB who underwent antiviral prophylaxis, TAF use was associated with a higher chance of HBV relapse than entecavir use after nucleos(t)ide analogue cessation, particularly in the high-viremia group. Patients who are hematologic malignancy and undergo a rituximab-containing cytotoxic therapy should be monitored closely after withdrawal from prophylactic NA treatment.

Safety and adherence of bictegravir/emtricitabine/tenofovir alafenamide for HIV post-exposure prophylaxis among adults in Guiyang China: a prospective cohort study.

BACKGROUND: The effectiveness of post-exposure prophylaxis (PEP) depends on participants adherence, making it crucial to assess and compare regimen options to enhance human immunodeficiency virus (HIV) prophylaxis strategies. However, no prospective study in China has shown that the completion rate and adherence of single-tablet regimens in HIV PEP are higher than those of multi-tablet preparations. Therefore, this study aimed to assess the completion rate and adherence of two HIV PEP regimens. METHODS: In this single-center, prospective, open-label cohort study, we included 179 participants from May 2022 to March 2023 and analyzed the differences in the 28-day medication completion rate, adherence, safety, tolerance, and effectiveness of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) and tenofovir disoproxil fumarate, emtricitabine, and dolutegravir (TDF/FTC + DTG). RESULTS: The PEP completion rate and adherence were higher in the BIC/FTC/TAF group than in the TDF/FTC + DTG group (completion rate: 97.8% vs. 82.6%, P = 0.009; adherence: 99.6 ± 2.82% vs. 90.2 ± 25.29%, P = 0.003). The incidence of adverse reactions in the BIC/FTC/TAF and TDF/FTC + DTG groups was 15.2% and 10.3% (P = 0.33), respectively. In the TDF/FTC + DTG group, one participant stopped PEP owing to adverse reactions (1.1%). No other participants stopped PEP due to adverse events. CONCLUSIONS: BIC/FTC/TAF and TDF/FTC + DTG have good safety and tolerance as PEP regimens. BIC/FTC/TAF has a higher completion rate and increased adherence, thus, is recommended as a PEP regimen. These findings emphasize the importance of regimen choice in optimizing PEP outcomes. TRIAL REGISTRATION: The study was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2200059994(2022-05-14), https://www.chictr.org.cn/bin/project/edit?pid=167391 ).

Risk of hepatocellular carcinoma after curative treatment when switching from tenofovir disoproxil fumarate or entecavir to tenofovir alafenamide: A real-world multicenter cohort study.

AIM: Antiviral treatment reduces the risk of developing hepatocellular carcinoma (HCC) in patients with chronic hepatitis B. However, there is a lack of high-quality evidence regarding the preventive effects of tenofovir alafenamide (TAF) on HCC. We evaluated the impact of TAF use after curative treatment on HCC recurrence. METHODS: Patients who underwent surgery or radiofrequency ablation as a curative treatment for HCC were selected. Those patients who continued antiviral treatment with nucleos(t)ide analogs (NAs; entecavir [ETV] or tenofovir disoproxil fumarate [TDF]) or switched to TAF were included. The primary outcome was HCC recurrence, and the time-varying effect of NA use on HCC recurrence was analyzed using various statistical methods. RESULTS: Among 2794 consecutive patients with chronic hepatitis B who received curative treatment for HCC, 199 subsequently switched from ETV or TDF to TAF. After a median of 3.0 years, 1303 patients (46.6%) experienced HCC recurrence. After propensity score matching (ratio 1:10), switching to TAF was not associated with an increased HCC recurrence (HR 1.00, 95% CI 0.68-1.47; p = 1.00) by time-varying Cox analysis. Switching to TAF was not associated with HCC recurrence in subgroups of NA (HR 1.06, 95% CI 0.67-1.67; p = 0.81 for TDF, and HR 1.09, 95% CI 0.51-2.33; p = 0.82 for ETV). Kaplan-Meier analysis showed comparable HCC recurrence-free survival between patients who switched to TAF and those who continued with their NA (p = 0.08). Time-varying Cox analyses in various subgroups confirmed the primary findings. CONCLUSIONS: TAF is as effective as TDF and ETV in preventing HCC recurrence after curative treatment.

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

AIM: Patients with chronic hepatitis B virus (HBV) infection experiencing viral breakthrough (BTH) or partial response (PR) during lamivudine (LAM) or entecavir hydrate (ETV) administration often took ETV plus tenofovir alafenamide fumarate (TAF) due to the emergence of a drug-resistance mutation. However, in patients lacking drug-resistance mutation against TAF, sufficient antiviral effects may be achievable with TAF monotherapy. We assessed the drug-resistance profile through nucleotide sequences of HBV pregenome RNA, and subsequently changed to TAF monotherapy from ETV plus TAF. METHODS: This prospective study included 25 patients with serum HBV-DNA below 20 IU/mL under ETV plus TAF administration. Pregenome RNA nucleotide sequences of HBV in the sera were analyzed using direct sequencing and deep sequencing. ETV was discontinued in patients without rtA194T and rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutations in direct sequencing. RESULTS: LAM-PR, LAM-BTH, ETV-PR, and ETV-BTH were observed in 1, 16, 7, and 1 patient(s), respectively. Pregenome RNA nucleotide sequences were analyzable in 20 patients. Among the 12 patients classified as LAM-BTH, six patients showed rtL180M + rtM204V/I in direct sequencing, and one patient showed minor clones containing rtL180M + rtM204V + A194T in deep sequencing at a frequency of 0.3%. In the six patients classified as ETV-PR, one patient harbored rtM204I. No clones showing rtS106C + rtH126Y + rtD134E + rtL269I quadruple mutation were detected in deep sequencing. Subsequently, ETV was discontinued, and serum HBV-DNA remained undetectable up to 48 weeks in all patients. CONCLUSION: Patients receiving ETV plus TAF due to partial response or BTH during initial LAM or ETV administration were able to safely transition to TAF monotherapy based on nucleotide sequences of HBV pregenome RNA in the sera.

Kinetics of the hepatitis B core-related antigen and treatment responses in chronic hepatitis B patients treated with tenofovir alafenamide.

AIM: An association between hepatitis B core-related antigen (HBcrAg) kinetics and hepatocarcinogenesis during nucleoside (t)id analog (NA) treatment has recently been reported. HBcrAg kinetics and factors associated with HBcrAg response during tenofovir alafenamide (TAF) administration remain unclear. In this multicenter retrospective study, we aimed to clarify the efficacy and safety of TAF in treatment-naïve patients with chronic hepatitis B, focusing on the reduction in HBcrAg levels. METHODS: Patients were treated with TAF monotherapy for 96 weeks, and the kinetics of HBcrAg during treatment and the factors associated with HBcrAg response (defined as a change in HBcrAg of -1 log IU/mL from baseline) were evaluated. RESULTS: The study population comprised 241 patients, 36.9% of whom were HBeAg-positive. The median baseline HBcrAg level was 4.7 log IU/mL. The median change in HBcrAg from baseline was -1.1 log IU/mL at 96 weeks after treatment. The HBcrAg response rate at 96 weeks was 56.6% (43/76). Multivariate analysis revealed high alanine transaminase level as an independent baseline factor associated with HBcrAg response at 96 weeks of treatment (p = 4.53 × 10-6). No correlation was found between the HBcrAg and hepatitis B surface antigen kinetics in patients treated with TAF monotherapy. CONCLUSIONS: In TAF monotherapy for patients with chronic hepatitis B, HBcrAg levels were significantly decreased and baseline alanine transaminase level is an important factor associated with HBcrAg reduction. As no correlation was found between HBcrAg and reduced hepatitis B surface antigen levels in this study, HBcrAg kinetics in addition to hepatitis B surface antigen may need to be monitored during TAF treatment.

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.

Effectiveness and Safety of Tenofovir Alafenamide Fumarate in the Prevention of Perinatal Hepatitis B Transmission: A Meta-Analysis.

AIM: This study aimed to assess the effectiveness and safety of tenofovir alafenamide fumarate (TAF) in the prevention of mother-to-child transmission (MTCT) of hepatitis B virus (HBV). METHODS: We performed a meta-analysis of studies from the Cochrane Library, PubMed, ClinicalTrials.gov, Web of Science, EMBASE, China National Knowledge Infrastructure (CNKI), China Medical Information Network, and Wanfang databases. The databases were searched from inception to January 7, 2023, for cohort studies and randomized controlled trials (RCTs) comparing the use of TAF antivirals to other antivirals during pregnancy. We combined the data by means of a random-effect DerSimonian-Laird model and risk ratios (RRs) or a random-effect inverse variance model and standardized mean differences (SMDs) to determine the influence on mothers and infants. Our primary outcomes were infant weight, height, head size, birth defects, and Apgar scores. Additionally, we assessed whether newborns tested positive for hepatitis B surface antigen (HBsAg) at birth and at six months of age. The secondary outcomes of our investigation were alterations in levels of HBV deoxyribonucleic acid (DNA), alanine aminotransferase (ALT), total bilirubin (TBIL), blood creatinine, and urine ß2-microglobulin (ß2-M) in mothers. RESULTS: An extensive literature search identified 216 relevant publications; three cohort studies and two RCTs were included in this study. A total of 341 mothers were treated with TAF, and 342 were treated with other antiviral agents. TAF was as effective as other antiviral medications at lowering HBV MTCT rates at birth and at 6 months of age and ALT, TBIL, and HBV DNA levels. Moreover, compared with other antiviral drugs, TAF did not affect infant weight, height, head size, Apgar scores, and birth defects or maternal blood creatinine or ß2-M levels. CONCLUSIONS: TAF antiviral therapy during pregnancy was found to be safe for both mothers and fetuses.

Evaluation of genotoxic and mitotoxic effects of TAF-loaded chitosan nanoparticles in HepG2 cells.

Tenofovir alafenamide (TAF) is a new drug from the nucleotide reverse transcriptase inhibitor group approved for the treatment of chronic Hepatitis B in 2016. With this study, we aimed to test whether possible cellular toxicity can be reduced by controlled drug release as a result of loading with chitosan nanoparticles (CHS). We investigated the genotoxic and mitotoxic effects of 45 µM TAF-loaded CHS and TAF-only on HepG2 cells by micronucleus (MN), comet assay, determination of mtDNA quantification, mitochondrial membrane potential (ΔΨm), and ROS levels. Additionally, we compared the samples by RNAseq analyses to reveal the transcriptional responses to each regimen. In terms of genotoxic tests, although MN and comet were found higher in all experimental treatment conditions, the encapsulation of CHS reduced the genotoxicity of TAF. MtDNA level was found to be lower in the TAF treatment, whereas it was higher in CHS and CHS-TAF treatments. The TAF-loaded CHS and TAF treatments had an impaired ΔΨm value. Cellular ROS levels were higher in all treatment conditions. According to the analyses of gene expression patterns; CHS-only changed the expression of relatively few genes (187 genes), while TAF changed the expression of the 1974 genes and TAF-loaded CHS changed the expression of 734 genes. Considering the gene expression numbers, CHS encapsulation of TAF significantly reduced the number of genes that were differentially expressed by TAF-only. Overall, we observed that TAF has genotoxic and mitotoxic effects on HepG2 cells, and upon encapsulation with CHS, its genotoxic and mitotoxic effects were decreased.

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.

Evaluation of Pharmacokinetics of a BCS Class III Drug with Two Different Study Designs: Tenofovir Alafenamide Monofumarate Film-coated Tablet.

Tenofovir alafenamide (TAF) is a BCS Class III compound and an oral pro-drug of Tenofovir (TFV) with limited oral bioavailability. The bioavailability of the oral intake increases with food as a result of the low stability of the active substance in the stomach. The reference drug is "Vemlidy® 25 mg Film Tablet", which contains 25 mg of TAF in "hemifumarate" form, is under patent protection until 15.08.2032 by Gilead, and so the "monofumarate" form was used in the present study. At first, a pilot study was conducted involving 12 subjects under fed conditions. The results of the pilot study revealed the test and reference products were not bioequivalent, as a result of insufficient statistical power and high inter-subject variability. Secondly, a physiologically based pharmacokinetic (PBPK) simulation was performed based on the pilot study results and literature data. Finally, the power of the design was increased and the pivotal study design was optimized into a four-period, full-replicated, cross-over study with 34 subjects under fed conditions and it was concluded that the test and reference products were bioequivalent. In conclusion, the present study proved the importance of a correct study design with higher statistical power for a BCS Class III compound with high variability, to present the pharmacokinetics.

Weight and Metabolic Changes After Switching From Tenofovir Alafenamide/Emtricitabine (FTC)+Dolutegravir (DTG), Tenofovir Disoproxil Fumarate (TDF)/FTC + DTG, and TDF/FTC/Efavirenz to TDF/Lamivudine/DTG.

Participants randomized to first-line tenofovir alafenamide (TAF)/emtricitabine (FTC)+dolutegravir (DTG), tenofovir disoproxil fumarate (TDF)/FTC + DTG, or TDF/FTC/efavirenz (EFV) for 192 weeks were then switched to TDF/lamivudine (3TC)/DTG for 52 weeks. Participants switching either TAF/FTC + DTG or TDF/FTC/EFV to TDF/3TC/DTG showed statistically significant reductions in weight, low-density lipoprotein, triglycerides, glucose and glycated hemoglobin.

Metabolic-Related Outcomes After Switching From Tenofovir Disoproxil Fumarate to Tenofovir Alafenamide in Adults With Human Immunodeficiency Virus (HIV): A Multicenter Prospective Cohort Study.

BACKGROUND: Tenofovir alafenamide (TAF) has replaced tenofovir disoproxil fumarate (TDF) in many clinical settings. However, concerns remain about potential metabolic complications of TAF. We aimed to evaluate changes in weight, laboratory markers, and metabolic-related clinical events after replacing TDF with TAF. METHODS: Multicenter prospective cohort study in the Spanish CoRIS cohort. We included virologically suppressed adults with human immunodeficiency virus (HIV) receiving TDF for more than 12 months who either switched to TAF or maintained TDF, with no changes in the core agent. Participants were matched by propensity score. We fitted generalized equation models to assess changes in weight, blood lipids, and hepatic steatosis index, and to compare the incidence of diabetes, hypertension, and lipid-lowering drug use after 144 weeks. RESULTS: In total, 1446 participants were matched in each group. Median age was 38 years, 85% were male, mean weight at baseline was 73 kg. Participants who switched to TAF had a mean weight increase of +0.5 kg at 144 weeks over those who maintained TDF, with no difference in the occurrence of overweight or obesity. Individuals who switched to TAF had a significant increase in total cholesterol (+7.9 mg/dL) and triglycerides (+11.2 mg/dL), with no differences in the total cholesterol-high-density lipoprotein (HDL) ratio. However, no increased incidence of diabetes, hypertension, or lipid-lowering drug use was observed after the follow-up period. CONCLUSIONS: Switching from TDF to TAF is associated with modest weight gain and increases in total cholesterol and triglycerides, without an impact on the incidence of obesity or metabolic-related clinical events, in this Spanish cohort with a majority White male population.

Urine Tenofovir Levels Strongly Correlate With Virologic Suppression in Patients With Human Immunodeficiency Virus on Tenofovir Alafenamide-Based Antiretroviral Therapy.

We found that urine tenofovir (TFV) levels >1500 ng/mL strongly predict virologic suppression among people with human immunodeficiency virus taking tenofovir alafenamide (odds ratio, 5.66; 95% confidence interval, 1.59-20.14; P = .007). This suggests an existing point-of-care assay developed for tenofovir disoproxil fumarate will support adherence monitoring for patients on all TFV-based antiretrovirals.