Adefovir Research Articles

Investigation of hepatitis B virus mutations associated with immune escape and drug resistance in human immunodeficiency virus-infected patients

Background Co-infection of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) has an impact on high HBV replication and progression to liver cancer. These may lead to cross-resistance of drugs due to therapeutic pressure or liver toxicity. These require continuous monitoring of HBV variants for better diagnosis and treatment strategies. Methods Convenience sampling was used to collect fifty archival sera from Inkosi Albert Luthuli Central Hospital. The Sera were subjected to HBsAg screening using ELISA, DNA extraction, PCR amplification, Sanger sequencing, phylogenetic and mutation analysis. A correlation test was performed to measure the association between polymerase and surface mutations. Results Of the 50 samples, 86% (N= 43/50) were HBsAg positive; 82% (N=41/50) PCR positive and 92% (N=38/41) sequenced. The HBV sequences showed similarity to genotype A (73% [N=19/26]) and (24% [N=7/26]) as genotypes B, C, D, E, F, and G. Prevalence of the mutations in the Surface region was (47% [N=18/38]); including diagnostic failure (K122R and T143S) and vaccines escape mutations (P127T, G145R, S207N, Y200T, E164D, Y206H and L209V). The mutations in the RT was at (36% [N=14/38]) with drug resistance mutations (DRM) at (50% [7/14]). Mutations showed resistance to lamivudine (LMV) at (35% [5/14]), telbivudine (LdT) at (29% [4/14]), (14% [2/14]) for entecavir (ETV) and (21% [3/14]) for adefovir (ADV). One sample had a combination of L180M, M204V, S202K, and M250I mutations. There was no statistical significance between S and RT mutations at P>0.005 and the statistical correlation between RT and SHB mutations was weak at 0.877. Conclusions Our findings highlight the prevalence of HBV genotype A in HIV-infected patients in South Africa. We provide evidence of mutations linked to immune evasion and drug resistance. Mutations have no statistical significance but can have clinical Implication on the diagnosis and treatment of HBV in HBV/HIV co-infected individuals.

Understanding adefovir pharmacokinetics as a component of a transporter phenotyping cocktail

PurposeAdefovir (as dipivoxil) was selected as a probe drug in a previous transporter cocktail phenotyping study to assess renal organic anion transporter 1 (OAT1), with renal clearance (CLR) as the primary parameter describing renal elimination. An approximately 20% higher systemic exposure of adefovir was observed when combined with other cocktail components (metformin, sitagliptin, pitavastatin, and digoxin) compared to sole administration. The present evaluation applied a population pharmacokinetic (popPK) modeling approach to describe adefovir pharmacokinetics as a cocktail component in more detail.MethodsData from 24 healthy subjects were reanalyzed. After establishing a base model, covariate effects, including the impact of co-administered drugs, were assessed using forward inclusion then backward elimination.ResultsA one-compartment model with first-order absorption (including lag time) and a combination of nonlinear renal and linear nonrenal elimination best described the data. A significantly higher apparent bioavailability (73.6% vs. 59.0%) and a lower apparent absorption rate constant (2.29 h−1 vs. 5.18 h−1) were identified in the combined period compared to the sole administration period, while no difference was seen in renal elimination. The population estimate for the Michaelis-Menten constant (Km) of the nonlinear renal elimination was 170 nmol/L, exceeding the observed range of adefovir plasma maximum concentration, while the maximum rate (Vmax) of nonlinear renal elimination was 2.40 µmol/h at the median absolute estimated glomerular filtration rate of 105 mL/min.ConclusionThe popPK modeling approach indicated that the co-administration primarily affected the apparent absorption and/or prodrug conversion of adefovir dipivoxil, resulting in the minor drug-drug interaction observed for adefovir as a victim. However, renal elimination remained unaffected. The high Km value suggests that assessing renal OAT1 activity by CLR has no relevant misspecification error with the cocktail doses used.

Role of mitochondrial autophagy and the curative effect of rehmannia glutinosa leaves total glycoside capsules on nucleos(t)ide drug-induced renal injury

Objective: To study the curative effect of rehmannia glutinosa leaves total glycoside capsules and the role of mitochondrial autophagy on nucleos(t)ide drug-induced renal injury. Methods: Adefovir dipivoxil (ADV) was used to construct a hepatitis B virus (HBV) transgenic mouse model for renal injury. Renal function was measured in each group at one and two weeks of modeling. Mitochondrial autophagy indicators were measured at two weeks of modeling in renal tissue. Transmission electron microscopy was used to detect mitochondrial autophagy phenomena in renal tissue. The model was established for two weeks. Mouse with renal injury were treated with rehmannia glutinosa leaves total glycoside capsules or isotonic saline for eight weeks by intragastric administration. Renal function was measured. Renal tissue morphology was observed. Mitochondrial autophagy indicators were detected in renal tissue. The protective effect of different concentrations of verbascoside (the main active ingredient of rehmannia glutinosa capsule) was observed on HK-2 cell damage induced by ADV. HK-2 cells were divided into control, ADV, and ADV plus verbascoside groups. The effects of verbascoside at different times and concentrations were observed on the HK-2 mitochondrial autophagy indicators. Fifty patients with chronic hepatitis B were collected who presented with renal injury after treatment with nucleos(t)ide analogs. The random number method was used to divide 29 cases into a control group that received conventional treatment. The treatment group of 21 cases was treated with rehmannia glutinosa leaves total glycoside capsules on the basis of the control group. Serum creatinine (Scr) and urinary protein were detected at eight weeks.The χ(2) test or t-test was used for statistical analysis. Results: Compared with the control group, two weeks of modeling in the ADV group induced renal function injury in HBV mice. The expression of autophagy indicators was higher in the renal tissue of the ADV group than that of the control group. Transmission electron microscopy had revealed mitochondrial autophagy in the renal tissue of the ADV group. Compared with the control group, the renal function of HBV mice treated with rehmannia glutinosa leaves total glycoside capsules improved for two months, and the expressions of autophagy indicators were down-regulated.Verbascoside promoted proliferation in ADV-damaged HK-2 cells, and the expression of autophagy indicators was down-regulated compared with the ADV alone group. In 50 patients with renal function injury, the urinary protein improvement was significantly superior in the treatment group than that in the control group, with eighteen and three cases being effective and ineffective in the treatment group and 12 and 17 cases being effective and ineffective in the control group, with a statistically significant difference (χ(2) = 9.975 0, P = 0.001 6). Serum creatinine was decreased in the treatment group compared with the control group, with 11 and 10 cases being effective and ineffective in the treatment group and 12 and 17 cases being effective and ineffective in the control group, with no statistically significant difference (χ(2) = 0.593 5, P = 0.441 1). Conclusion: Rehmannia glutinosa leaves total glycoside capsule can improve the nucleos(t)ide drug-induced renal function injury in chronic hepatitis B, possibly playing a role via inhibiting PINK1/Parkin-mediated mitochondrial autophagy.

Effect of Adefovir Dipivoxil on the Inhibition of Osteogenic Differentiation of Mesenchymal Stem Cells and Osteoblasts

Effect of Adefovir Dipivoxil on the Inhibition of Osteogenic Differentiation of Mesenchymal Stem Cells and Osteoblasts

Switching from tenofovir disoproxil fumarate to tenofovir alafenamide fumarate in a cohort of patients with HBV infection: A retrospective study

BackgroundTenofovir disoproxil fumarate (TDF) as first-line therapy for chronic HBV infection is related to nephrotoxicity. Tenofovir alafenamide fumarate (TAF) has been approved with a similar virological and serological response, but lower toxicity. TAF is available for older patients, with bone or kidney impairment. MethodsThe primary objective was the evaluation of renal function modification in patients who are switching from TDF to TAF; secondary objective was the use of urinary concentration of tenofovir (TFV) as early marker of renal function improvement or worsening.Retrospective study including all HBV patients treated with TDF or TAF. Two groups were selected: patients who are switched from TDF to TAF and who continued with TDF. Follow-up was six months. Results42 subjects were included; 17 were in TAF group (40 %) and 25 in TDF group (60 %). In TDF group, no estimated glomerular filtration rate (eGFR) improvement was observed, while in TAF group increased by 9 ml/min (p < 0.001). Urinary TFV levels increased by 3 ng/mL in TDF group and decreased by 4.5 ng/mL in TAF group (p < 0.001). The relationship between the eGFR and urinary TFV resulted in reverse proportionality (R2 = -0.740, p = 0.001) between the two variables. In multivariate analysis eGFR (β = 0.880, p = 0.043) and pretreatment wit adefovir dipivoxil (ADV) resulted significantly related to TFV urinary excretion. ConclusionsSwitching from TDF to TAF lead to significant improvement in eGFR and lower toxicity (estimated with TFV urinary excretion) at six months of follow-up. ADV pretreatment should be considered as adjunctive risk factor for nephrotoxicity independently from age and eGFR.

Synergistic Activity of Adefovir Dipivoxil and Venetoclax to Target the Bioenergetic Metabolism of Acute Myeloid Leukemia

Adefovir dipivoxil (ADV) is an oral prodrug of the nucleotide analogue adefovir that inhibits viral DNA polymerase and is an FDA-approved drug for the treatment of hepatitis B virus. Preliminary evidence of the antileukemic activity of ADV was recently reported in a patient with acute promyelocytic leukemia (APL; Gong, X., et al. Exp Hematol Oncol, 2022). Herein we report on the antileukemic activity of ADV, alone and in combination with venetoclax (VEN), an oral FDA-approved BCL-2 inhibitor for the treatment of acute myeloid leukemia (AML). Firstly, a significant dose-dependent reduction of cell growth and increase in apoptosis were observed in FLT3-ITD+ MV4-11 (IC50: 97nΜ) and Molm-13 (IC50: 0.816μM) cells, and in primary CD34+ blasts from refractory/relapsed (R/R) AML patients (n=5; IC50: 1.285-3.703μM), exposed to serial concentrations of ADV for 48 hours (hrs). In contrast, no significant changes were observed in ADV-treated CD34+ cells from healthy donors (n=5). Combination of ADV and VEN were synergistic (combination index &amp;lt; 1.0) in reducing cell viability of AML cells (i.e., MV-4-11, U937, KG1 and THP-1) and CD34+ blasts from R/R AML patients (n=3). To gain insights into the molecular mechanisms underlying the antileukemic activity of ADV alone and in combination with VEN, we performed RNA-Seq on AML CD34+ blasts from R/R AML patients (n=6) treated with vehicle, ADV (5 μΜ), VEN (100 nΜ), or ADV+VEN for 24 hrs. Gene set enrichment analysis (GSEA) highlighted upregulation of p53 pathway and apoptosis signaling, and downregulation of oxidative phosphorylation (OXPHOS), glycolysis, and MYC target hallmark gene sets in ADV- and ADV+VEN-treated cells compared with vehicle-treated controls. These results were confirmed by western blot analysis showing a dose-dependent reduction in c-MYC, anti-apoptotic proteins (i.e., BCL-2 and MCL-1), and carnitine palmitoyltransferase-1a [CPT1A, a key enzyme for fatty acid oxidation (FAO), a process that feeds into OXPHOS], and an increase in pro-apoptotic proteins (i.e., BAX and BAK) in ADV- and ADV+VEN-treated MV4-11 and primary AML CD34+ cells, compared with vehicle-treated control cells. Seahorse analysis confirmed a significant reduction of OXPHOS [measured by oxygen consumption rate (OCR)], associated with decreased mitochondrial numbers and sizes evaluated by electron microscopy imaging of AML CD34+ blasts treated with ADV or ADV+VEN compared with vehicle-treated controls. To test in vivo the antileukemic activity of ADV+VEN, we treated a cohort of CD45.1 recipient mice transplanted with BM cells from congenic CD45.2 Mll PTD/WT/Flt3 ITD/ITD AML mice with vehicle, ADV (100mg/kg, oral gavage), VEN (100mg/kg, oral gavage), or ADV+VEN (n=10 per group) for 4 weeks. ADV+VEN-treated mice lived longer (median survival: 60 days after treatment completion) than ADV (20 days, p=0.0001), VEN (20 days, p=0.0001), or vehicle (14 days, p=0.0002) -treated controls (Figure 1). We then performed secondary transplants by engrafting 10 6 BM cells from treated donors into CD45.1 recipient mice (n=10 per group). Recipients of BM from ADV+VEN-treated donors survived longer (median survival: 83 days) than recipients of BM from ADV (60.5 days, p&amp;lt;0.01), VEN (45.5 days, p&amp;lt;0.0001), and vehicle (42.5 days, p&amp;lt;0.0001) -treated donors (Figure 2), confirming a decrease in leukemic stem cell (LSC) burden by ADV+VEN. Next, we examined the antileukemic activity of ADV+VEN in human AML models. We first treated a cohort of NSG mice (n=10 per group) transplanted with luciferase-expressing Molm-13 cells. ADV+VEN-treated mice survived longer (median survival: 59.5 days) than ADV (52 days, p=0.04), VEN (40 days, p&amp;lt;0.0001), and vehicle (40.5 days, p&amp;lt;0.0001) -treated mice. We then treated a cohort of NSG mice (n=8 per group) transplanted with FLT3-ITD+ blasts from a patient with R/R AML. ADV+VEN-treated mice survived longer (median: 38.5 days) than ADV (34.5 days, p=0.035), VEN (25 days, p&amp;lt;0.0001), and vehicle (18.5 days, p&amp;lt;0.0001) -treated mice. In summary, ADV has in vivo anti-leukemic activity in AML likely by interfering with the bioenergetic metabolism of leukemic cells and decreasing their apoptotic threshold. The combination of ADV and VEN is seemingly synergistic and prolonged survival of murine and human AML models, providing a rationale of translating this “all oral” regimen to the clinic for treatment of AML patients, especially those requiring low intensity therapy.

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

Data on patients switched to tenofovir alafenamide (TAF) from nucleos(t)ide analogues (NUCs) other than tenofovir disoproxil fumarate are limited. To assess the treatment and renal/bone safety outcomes following the switch to TAF. We prospectively enrolled adult patients with chronic hepatitis B (CHB) who switched from any NUC to TAF at 14 centres in Japan, Korea, Taiwan and the U.S. Study outcomes were viral suppression (VR; HBV DNA < 20 IU/mL), biochemical response (BR; alanine aminotransferase normalisation), and changes in estimated glomerular filtration rate (eGFR) and T-scores (L-spine) by bone absorptiometry by 24 months after switch to TAF. We enrolled 270 eligible patients. Mean age was 58.1; 58.2% were male; 12.2% had cirrhosis and 73.3% previously received entecavir monotherapy. VR rate increased significantly from 95.2% to 98.8% by 24 months after the switch to TAF (p = 0.014). Between the switch and 24 months later, the mean spine T-score improved significantly from -1.43 ± 1.36 to -1.17 ± 1.38 (p < 0.0001), while there was no significant change in mean eGFR (88.4 ± 16.9-89.5 ± 16.3 mL/min/1.73 m2 , p = 0.13). On multivariable analysis adjusted for age, sex, baseline spine T-score and prior TDF or adefovir dipivoxil use, male sex was significantly associated with lower risk of worsening spine T-score (odds ratio: 0.29, p = 0.020), while age was significantly associated with a higher risk of worsening chronic kidney disease stage (OR: 1.07, p = 0.019). At 24 months after the switch to TAF, VR rates and spine bone density improved significantly while renal function remained stable.

High Frequency of Antiviral Resistance Mutations in HBV Genotypes A2 and H: Multidrug Resistance Strains in Mexico.

Lamivudine (3TC), telbivudine (LdT), entecavir (ETV), adefovir (ADF), and tenofovir (TFV) are drugs used to treat hepatitis B virus (HBV) infection, but specific mutations allow some viruses to become resistant to antiviral drugs or to acquire immune escape capacities. These mutations have not been thoroughly investigated in Mexico. This study aimed to estimate the prevalence of HBV antiviral resistance and escape mutations. This cross-sectional study analyzed 158 samples. HBV DNA was extracted, amplified, and sequenced in serum samples using the spin column method, PCR assay, and Sanger's sequencing, respectively. HBV genotypes were determined, and HBV mutations were tested using the Geno2pheno tool. Overall, 68.4% (108/158) of HBV patients were infected with genotype H, followed by G (11.4%, 18/158), A2 (10.8%, 17/158), F1b (6.9.0%, 11/158), D (1.9%, 3/158), and E (0.6%, 1/158), and 5.1% (8/158) had evidence of recombination. The prevalence of resistance mutations was 8.2% (13/158) and the most common combined mutation was rt180M+rt204V. Notably, we found the combinations rt180M+rt204V+rt173L (n=2) and rt180M+rt204V+rt202G (n=1) that confer multidrug resistance to 3TC, LdT, and ETV. Resistance mutations were found in genotypes A2 (11.8%, 2/17), and H (10.2%, 11/108), and escape mutations were detected in HBV genotypes A2 (11.8%, 2/17), H (10.2%, 11/108), F1b (9.1%, 1/11) and G (5.6%, 1/18). The highest prevalence of antiviral resistance mutations or escape mutations was detected in HBV genotypes A2 and H. The earliest cases of HBV multidrug resistance were detected in Mexico.

Antiviral activities of two nucleos(t)ide analogs against vaccinia, mpox, and cowpox viruses in primary human fibroblasts

Many poxviruses are significant human and animal pathogens, including viruses that cause smallpox and mpox (formerly monkeypox). Identifying novel and potent antiviral compounds is critical to successful drug development targeting poxviruses. Here we tested two compounds, nucleoside trifluridine, and nucleotide adefovir dipivoxil, for antiviral activities against vaccinia virus (VACV), mpox virus (MPXV), and cowpox virus (CPXV) in physiologically relevant primary human fibroblasts. Both compounds potently inhibited the replication of VACV, CPXV, and MPXV (MA001 2022 isolate) in plaque assays. In our recently developed assay based on a recombinant VACV expressing secreted Gaussia luciferase, they both exhibited high potency in inhibiting VACV replication with EC50s in the low nanomolar range. In addition, both trifluridine and adefovir dipivoxil inhibited VACV DNA replication and downstream viral gene expression. Our results characterized trifluridine and adefovir dipivoxil as strong poxvirus antiviral compounds and further validate the VACV Gaussia luciferase assay as a highly efficient and reliable reporter tool for identifying poxvirus inhibitors. Given that both compounds are FDA-approved drugs, and trifluridine is already used to treat ocular vaccinia, further development of trifluridine and adefovir dipivoxil holds great promise in treating poxvirus infections, including mpox.

Adefovir Dipivoxil as a Therapeutic Candidate for Medullary Thyroid Carcinoma: Targeting RET and STAT3 Proto-Oncogenes.

Aberrant gene expression is often linked to the progression of various cancers, making the targeting of oncogene transcriptional activation a potential strategy to control tumor growth and development. The RET proto-oncogene's gain-of-function mutation is a major cause of medullary thyroid carcinoma (MTC), which is part of multiple endocrine neoplasia type 2 (MEN2) syndrome. In this study, we used a cell-based bioluminescence reporter system driven by the RET promoter to screen for small molecules that potentially suppress the RET gene transcription. We identified adefovir dipivoxil as a transcriptional inhibitor of the RET gene, which suppressed endogenous RET protein expression in MTC TT cells. Adefovir dipivoxil also interfered with STAT3 phosphorylation and showed high affinity to bind to STAT3. Additionally, it inhibited RET-dependent TT cell proliferation and increased apoptosis. These results demonstrate the potential of cell-based screening assays in identifying transcriptional inhibitors for other oncogenes.

1248. Relationship Between ALT and New HBV Biomarkers in HBV/HIV Coinfected Persons Started on Antiviral Therapy

Abstract Background While HBV DNA has served as a primary biomarker of HBV infection, newer biomarkers including pre-genomic HBV RNA (pgRNA) and quantitative HBV surface antigen (qHBsAg) may prognosticate treatment responses better. We analyzed the changes in these biomarkers over time following initiation of antiviral therapy in persons living with HIV (PLWH) to determine the relationship to ALT, a key marker of liver injury. FigureBiomarker changes Methods NIH AIDS Clinical Trials Group Study 5127 enrolled HBV/HIV PLWH into a Phase 2 treatment trial that randomized them to receive 48 weeks of either tenofovir (TDF) or adefovir (ADV). ALT and HBV DNA were evaluated as measures of treatment response. Stored samples were tested for HBV pgRNA and qHBsAg at baseline, 4, 12, 24, 36, and 48 weeks. HBV pgRNA was isolated using RNA-selective extraction chemistry followed by a multiplex RT-qPCR that targets the HBV X and core targets on the m2000 system (Abbott Molecular, Des Plaines, Illinois). A sensitive second-generation assay with a lower limit of quantification (LLOQ) of 10 copies/mL was utilized. Quantitative HBsAg was determined by Abbott ARCHITECT (List# 6C36) with a LLOQ of 0.05 IU/mL. Data were analyzed using SAS® version 9.4. Results Overall, 47 study participants had sufficient samples for biomarker testing. Participants were predominantly male (93.6%) and identified as white, non-Hispanic (55.3%) or black (34%). Groups were evenly randomized to receive either TDF (n=23) or ADV (n=24). Baseline ALT mean was 64.9 U/L, and HBV DNA was 9.1 (+1.6) copies/mL. Pre-treatment pgRNA serum concentration was 7.0 (+1.3) log U/mL, and qHBsAg was 195,574 (+272,190) IU/mL. Over the course of treatment, pgRNA was significantly correlated with the change in serum ALT levels (r=0.48; p=0.0035) but not HBV DNA (r=0.21; p=0.226). ALT was negatively correlated with qHBsAg (r=-0.52; p=0.02). pgRNA was also highly negatively correlated with qHBsAg (r=-0.49l; p=0.03) but not HBV DNA (r=0.13; p=0.59). (Figure). Conclusion HBV pgRNA is a better predictor of ALT change – a key measure of hepatocyte injury – than HBV DNA in PLWH who are initiated on nucleotide/nucleoside therapy. Quantitative HBsAg is inversely associated with ALT levels, supporting the hypothesis that HBsAg inhibits immune mediated injury to hepatocytes. Disclosures Michael E. Stec, MSc, Abbott Laboratories: Employee of Abbott|Abbott Laboratories: Stocks/Bonds mark C. Anderson, PhD, Abbott Laboratories: Employment|Abbott Laboratories: Stocks/Bonds Marion G. Peters, MD, Aligos: Advisor/Consultant|antios: Advisor/Consultant|Excision Biotherapeutics: DSMB Gavin Cloherty, PhD, Abbott: Employee|Abbott: Stocks/Bonds|Abbott Labs: Employee.

Zirconium Molybdate Nanocomposites' Sensing Platform for the Sensitive and Selective Electrochemical Detection of Adefovir.

Adefovir (ADV) is an anti-retroviral drug, which can be used to treat acquired immune deficiency syndrome (AIDS) and chronic hepatitis B (CHB), so its quantitative analysis is of great significance. In this work, zirconium molybdate (ZrMo2O8) was synthesized by a wet chemical method, and a composite with multi-walled carbon nanotubes (MWCNTs) was made. ZrMo2O8-MWCNTs composite was dropped onto the surface of a glassy carbon electrode (GCE) to prepare ZrMo2O8-MWCNTs/GCE, and ZrMo2O8-MWCNTs/GCE was used in the electrochemical detection of ADV for the first time. The preparation method is fast and simple. The materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and cyclic voltammetry (CV). It was electrochemically analysed by differential pulse voltammetry (DPV). Compared with single-material modified electrodes, ZrMo2O8-MWCNTs/GCE showed a vastly improved electrochemical response to ADV. Moreover, the sensor complements the study of the electrochemical detection of ADV. Under optimal conditions, the proposed electrochemical method showed a wide linear range (from 1 to 100 μM) and a low detection limit (0.253 μM). It was successfully tested in serum and urine. In addition, the sensor has the advantages of a simple preparation, fast response, good reproducibility and repeatability. It may be helpful in the potential applications of other substances with similar structures.

Comparing the efficacy and safety of tenofovir and adefovir or combined drug treatment for the treatment of chronic hepatitis B infection: a systematic review and meta-analysis.

BackgroundChronic hepatitis B (CHB) affects a vast population globally. A variety of drugs are available for the treatment of CHB, including tenofovir (TDF) and adefovir (ADV). However, the efficacy of monotherapy drug treatment is inconclusive, the safety and efficacy of TDF remain unclear, more data are needed to be included and combined drug treatment is considered to exhibit higher efficacy. To explore this issue, we performed a current literature review and meta-analysis to compare the efficacy and safety of ADV vs. TDF, TDF vs. ADV + lamivudine (LAM); TDF vs. ADV + entecavir (ETV).MethodsWe systematically searched China National Knowledge Infrastructure, the Cochrane Library, Embase, PubMed, Chinese VIP, and Wanfang Data, for relevant clinical trials since July 2015, all included studies were based on PICOS principles and evaluated independently by the reviewers in accordance with the Cochrane Handbook (Rob2.0). A meta-analysis was performed by using Review Manager 5.4.ResultsWe included a total of 32 studies, including 31 randomized controlled trials and one retrospective study involving 2,473 patients. The results revealed a low risk of bias in included studies, that the virologic response of TDF was superior to ADV (P<0.05). And TDF was also superior to ADV in Serum creatinine levels, Immunologic function, and safety profile. However, when ADV was combined with other medications, it was superior to TDF in alanine aminotransferase (ALT) level and Tbil level and adverse reactions, but on other indicators, TDF was superior to drug combination therapy.ConclusionsResults showed that TDF was superior to ADV in the parameters of ALT, hepatitis B virus (HBV)-DNA reduction, HBeAg-negative conversion rate, safety, and total bilirubin levels in patients with CHB. However, when ADV was combined with LAM or ETV, they often showed the same therapeutic effect as TDF in parameters such as ALT level and Tbil level and combined therapy can effectively reduce the occurrence of adverse reactions. In this study, because the sample source countries were limited, a greater number of global studies are needed in the future to verify the current findings.

Drug-induced Fanconi syndrome in patients with kidney allograft transplantation

BackgroundPatients after kidney transplantation need to take long-term immunosuppressive and other drugs. Some of these drug side effects are easily confused with the symptoms of Fanconi syndrome, resulting in misdiagnosis and missed diagnosis, and causing serious consequences to patients. Therefore, improving awareness, early diagnosis and treatment of Fanconi syndrome after kidney transplantation is critical.MethodsThis retrospective study analyzed 1728 cases of allogeneic kidney transplant patients admitted to the Second Xiangya Hospital of Central South University from July 2016 to January 2021. Two patients with Fanconi syndrome secondary to drugs, adefovir dipivoxil (ADV) and tacrolimus, were screened. We summarized the diagnostic process, clinical data, and prognosis.ResultsThe onset of Fanconi syndrome secondary to ADV after renal transplantation was insidious, and the condition developed after long-term medication (>10 years). It mainly manifested as bone pain, osteomalacia, and scoliosis in the late stage and was accompanied by obvious proximal renal tubular damage (severe hypophosphatemia, hypokalemia, hypocalcemia, hypouricemia, glycosuria, protein urine, acidosis, etc.) and renal function damage (increased creatinine and azotemia). The pathological findings included mitochondrial swelling and deformity in renal tubular epithelial cells. The above symptoms and signs were relieved after drug withdrawal, but the scoliosis was difficult to rectify. Fanconi syndrome secondary to tacrolimus has a single manifestation, increased creatinine, which can be easily confused with tacrolimus nephrotoxicity. However, it is often ineffective to reduce the dose of tacrolomus, and proximal renal failure can be found in the later stage of disease development. There was no abnormality in the bone metabolism index and imageological examination findings. The creatinine level decreased rapidly, the proximal renal tubule function returned to normal, and no severe electrolyte imbalance or urinary component loss occurred when the immunosuppression was changed from tacrolimus to cyclosporine A.ConclusionsFor the first time, drug-induced Fanconi syndrome after kidney transplantation was reported. These results confirmed that the long-term use of ADV or tacrolimus after kidney transplantation may have serious consequences, some of which are irreversible. Greater understanding of Fanconi syndrome after kidney transplantation is necessary in order to avoid incorrect and missed diagnosis.

Susceptibility of Drug Resistant Hepatitis B Virus Mutants to Besifovir.

Currently, interferon alpha and nucleos(t)ide analogues (NAs) are clinically available to treat hepatitis B virus (HBV) infection. Several NAs, including lamivudine (LMV), adefovir (ADV), entecavir (ETV) and tenofovir (TDF or TAF) have been approved and administered to chronic hepatitis B (CHB) patients. NAs inhibit HBV DNA synthesis by targeting the reverse transcriptase (RT) domain of HBV polymerase. Several mutations in the RT domain which lead to drug resistance against NAs have been reported, even for TDF and TAF which are highly potent with very low resistance rate. Besifovir (BFV) is a new antiviral dGMP analogue able to be used as a new NA drug for the control of CHB infection. Drug resistance to BFV is not well known due to its shorter duration of clinical use. Recently, we reported that rtL180M (M) and rtM204V (V) mutations, already resistant to LMV, are associated with BFV resistance. However, the susceptibility to BFV of previously known HBV mutants resistant to various drugs has not been studied. To investigate this, we performed in vitro drug susceptibility assays using natural and artificial mutants that are associated with resistance to LMV, ADV, ETV or TDF. As a result, LMV-resistant mutants were not susceptible to BFV and ETV-resistant clones showed partial resistance against BFV as well. However, ADV-resistant mutants were highly sensitive to BFV. In case of tenofovir-resistant mutations, the HBV mutants harboring primary mutations to tenofovir resistance were susceptible to BFV. Therefore, our study revealed that BSV may serve as an alternative drug for patients with ADV-, ETV-, TDF- or TAF-resistance.

Role of plasmatic and urinary concentration of tenofovir disoproxil fumarate in a cohort of patients affected by chronic hepatitis B.

The aim of this study was to evaluate plasmatic and urinary therapeutic drug monitoring (TDM) of tenofovir disoproxil fumarate (TDF) in a cohort of patients with chronic hepatitis B (CHB). In 68 enrolled patients, the estimated glomerular filtration rate (eGFR) was 68 mL/min in naive subjects, while in adefovir dipivoxil (ADV)-pretreated patients, it was 55.5 mL/min (p < 0.001). The HBV E genotype was associated with lower TDF levels (β = -0.698, p < 0.001). The urinary TDF concentration was associated with ADV pretreatment (β = 0.829, p < 0.001). Determination of urinary concentrations of TDF may be useful in the clinical management of older CHB patients and those with previous treatment with ADV.

Effects of nucleos(t)ide analogs on hepatitis B surface antigen reduction with interferon-lambda 3 induction in chronic hepatitis B patients.

Benefits of nucleos(t)ide analogs (NAs) on hepatitis B surface antigen (HBsAg) reduction and interferon-lambda3 (IFN-λ3) induction are still not known. This study aimed to investigate the effects of NAs on HBsAg reduction and association with serum IFN-λ3 levels in chronic hepatitis B (CHB) patients. A total of 91 patients [51 treated with nucleoside analog entecavir hydrate (ETV) and 40 treated with nucleotide analog adefovir dipivoxil (ADV) or tenofovir disoproxil fumarate (TDF)] with clinically evident CHB (chronic hepatitis, 57; liver cirrhosis, 34) were enrolled in this study. Serum IFN-λ3 levels among patients receiving ETV and ADV/TDF were measured before the initiation of therapy and 1, 3, and 5years post-therapy. The change (mean±standard deviation) in serum HBsAg levels from baseline to year five was -0.38±0.46 and -0.84±0.64 log10 IU/ml in ETV and ADV/TDF groups, respectively (p=0.0004). Higher serum IFN-λ3 levels were observed in ADV/TDF group compared with ETV group during treatment (p<0.001). Serum IFN-λ3 levels showed negative correlation with HBsAg reduction in ADV/TDF group (r = -0.386, p = 0.038) at week 48. Nucleotide analogs (ADV/TDF) treatment has associated factors with -0.3 log HBsAg decline at 1year, -0.5 log HBsAg decline at 3years, and -0.8 log HBsAg decline at 5years after NAs treatment on multivariate analysis. Nucleotide analog (ADV/TDF) treatment reduced HBsAg levels greater compared with nucleoside analog (ETV) in parallel with IFN-λ3 induction.

Purification and mass spectrometry study of Maillard reaction impurities in five acyclic nucleoside antiviral drugs

Maillard degradation products may lead to a decrease in active pharmaceutical ingredients and an increase in harmful substances. In this study, five acyclic nucleoside antiviral drugs (adefovir dipivoxil, famciclovir, tenofovir dipivoxil, acyclovir, and ganciclovir) were studied. Compatibility of APIs and lactose was performed, and the Maillard reaction products were monitored by HPLC–photodiode array detection and UHPLC–ESI–MS. Eight Maillard reaction products were detected, of which six were found to be new stable compounds (impurities 1–6) and were purified and identified by NMR spectroscopy. Moreover, the six new impurities were analyzed by MS/MS, and their mass spectrometric fragmentation mechanisms were proposed. The loss of a neutral fragment at 282 Da by the fragmentation of the lactose moiety was observed in the tandem mass spectra of all the impurities. This is the first systematic study of the Maillard reaction in the case of acyclic nucleosides antiviral drugs, and it has achieved good results. The results will be helpful for understanding the mass spectrometric fragmentation mechanisms of Maillard reaction products and the stability of acyclic nucleosides, and will provide suggestions for maintaining the stability and optimizing the storage and transportation conditions of these drugs.

Adefovir accumulation in the renal interstitium triggers mast cell degranulation and promotes renal interstitial fibrosis

Organic anion transporters 1 (OAT1) and OAT3 are responsible for transporting adefovir (ADV) into renal tubular epithelial cells. Our previous research found that ADV accumulated in the renal interstitium and caused renal interstitial fibrosis when Oat1/3 were inhibited by OATs inhibitor probenecid for long-term. Mast cells (MCs) in the interstitial space are considered to be key drivers of renal fibrosis. The current work investigated the effect of ADV on MCs in vitro and during the development of interstitial fibrosis in rats. Results indicate that ADV triggers chymase release from cultured RBL-2H3 mast cells in a time-and concentration-dependent manner. Angiotensin II (Ang II) in renal interstitium is generated mainly by chymase, renin and other products released from MCs, and has a direct effect on fibrosis through the angiotensin receptor. The concentrations of Ang II and fibrosis was significantly increased after administration of ADV alone or with probenecid for 4 weeks. The MCs membrane stabilizer sodium cromoglycate (SCG) and the angiotensin receptor antagonist Valsartan (VAL) could ameliorate ADV-induced nephrotoxicity. Additionally, SCG or VAL could reduce the accumulation of ADV in the renal interstitium by upregulating the expression of Oat1/3 and multidrug resistance-associated protein 4. Therefore, ADV accumulation in the renal interstitium could promote the degranulation of interstitial MCs and drive the development of renal fibrosis. SCG or VAL could ameliorate ADV-associated fibrosis by decreasing degranulation of MCs and accelerating renal clearance of ADV.

Telbivudine Plus Adefovir Versus Lamivudine Plus Adefovir for Lamivudine-Resistant Chronic Hepatitis B: TeSLA Randomized Trial

Background: In countries with unavailable tenofovir, a combination of lamivudine (LMV) and adefovir (ADV) is recommended for the treatment of LMV-resistant chronic hepatitis B (CHB). Considering that telbivudine (L-dT) was demonstrated to be superior to LMV in previous studies, L-dT and ADV combination therapy is expected to show better antiviral efficacy than the combination of LMV and ADV in patients with LMV-resistant CHB. Methods: This was a prospective randomized multicenter study. The primary endpoint was Hepatitis B Virus (HBV) DNA reduction after 52 weeks of treatment. The secondary endpoints were HBV DNA undetectability, hepatitis B e antigen seroconversion, the incidence of virological and biochemical breakthroughs, and safety during the study period. Results: A total of 43 LMV-resistant CHB patients were enrolled. Twenty-one were treated with LMV + ADV and 22 with L-dT + ADV. After 52 weeks of antiviral treatment, the HBV DNA reduction showed no significant intergroup difference (-4.54 ± 1.23 log IU/mL in the LMV + ADV group, -4.24 ± 1.46 log IU/mL in the L-dT + ADV group, P = 0.475). There were no significant intergroup differences in HBV DNA undetectability rates, mean HBV DNA level, or hepatitis B e antigen seroconversion rate at 13, 26, 39, and 52 weeks of treatment. In terms of safety, the mean creatine phosphokinase level was significantly higher in the L-dT + ADV group. Conclusions: In the treatment of LMV-resistant CHB, the combination of L-dT and ADV did not show any clinical benefit compared to the combination of LMV and ADV.