Predictive role of early treatment dynamics of HBV RNA and HBcrAg for HBeAg seroconversion in children with chronic hepatitis B.

This study aimed to assess the predictive capacity of emerging serological markers, serum HBV RNA and HBcrAg, for HBeAg seroconversion in children with HBeAg-positive chronic hepatitis B (CHB). Treatment-naïve HBeAg-positive CHB children who admitted to the Liver Disease Center of Hunan Children's Hospital between April 2021 and September 2022 and received treatment with the combined entecavir and interferon-alpha treatment were recruited. Serum HBV RNA and HBcrAg were measured at baseline and Weeks 12, 24, and 48 of treatment. Our study showed that serum HBV RNA (HR = 0.71, 95% CI: 0.56-0.91, p = 0.006), HBcrAg (HR = 0.60, 95% CI: 0.43-0.84, p = 0.003), and HBsAg (HR = 0.49, 95%CI: 0.36-0.69, p < 0.001) at Week 12 were independent predictors of HBeAg seroconversion. ROC curve analysis presented that serum HBV RNA decline value (ΔHBV RNA) at Week 36 and HBcrAg decline value (ΔHBcrAg) at Week 12 (AUC = 0.871, p = 0.003 and AUC = 0.810, p = 0.003, respectively) could effectively predict HBeAg seroconversion. Furthermore, the optimal critical values were determined and the children with ΔHBV RNA > 3.759 log10 copies/mL at Week 36 or ΔHBcrAg >0.350 log10 U/mL at Week 12 more likely to achieve HBeAg seroconversion. The serum HBV RNA and HBcrAg provide new insights into the treatment of CHB in children. Early assessment of serum HBV RNA and HBcrAg during treatment can assist clinical decision-making and optimize individualized therapeutic approaches.

Long-term antiviral therapy is associated with changes in the profile of transcriptionally active HBV integration in the livers of patients with CHB.

Hepatitis B virus (HBV) integration exists throughout the clinical course of chronic hepatitis B (CHB). This study investigated the effects of long-term antiviral therapy on the level and profiles of transcriptionally active HBV integration. Serial liver biopsies and paired blood samples were obtained from 16, 16, and 22 patients with CHB at baseline, 78, and 260 weeks of entecavir monotherapy or combined with pegylated interferon alfa, respectively. Serum HBV biomarkers were longitudinally assessed. RNA-seq and HIVID2 program was used to identify HBV-host chimeric RNAs transcribed from integrated DNA. The counts of HBV integration reads were positively related to both serum HBV DNA levels (r = 0.695, p = 0.004) and HBeAg titers (r = 0.724, p = 0.021) at baseline, but the positive correlation exited only to the serum HBsAg levels after 260 weeks of antiviral therapy (r = 0.662, p = 0.001). After 78 weeks of antiviral therapy, the levels of HBV integration expression decreased by 12.25 folds from baseline. The viral junction points were enriched at the S and HBx genes after the long-term antiviral therapy. HBs-FN1 became one of the main transcripts, with the mean proportion of HBs-FN1 in all integrated expression increased from 2.79% at baseline to 10.54% at Week 260 of antiviral treatment. Antiviral therapy may reduce but not eliminate the HBV integration events and integration expression. Certain integration events, such as HBs-FN1 can persist in long-term antiviral treatment.

Pilot Study of High-Dose Pemetrexed in Patients with Progressive Chordoma.

PURPOSE: Chordomas are ultrarare tumors of the axial spine and skull-base without approved systemic therapy. Most chordomas have negative expression of thymidylate synthase (TS), suggesting a potential for responding to the antifolate agent pemetrexed, which inhibits TS and other enzymes involved in nucleotide biosynthesis. We evaluated the therapeutic activity and safety of high-dose pemetrexed in progressive chordoma. PATIENTS AND METHODS: Adult patients with previously treated, progressive chordoma participated in an open-label, single-institution, single-arm, pilot clinical trial of intravenous pemetrexed 900 mg/m2 every 3 weeks and supportive medications of folic acid, vitamin B12, and dexamethasone. The primary endpoint was objective response rate according to RECIST v1.1. Secondary endpoints included adverse events, progression-free survival (PFS), tumor molecular profiles, and alterations in tissue and blood-based biomarkers. RESULTS: Fifteen patients were enrolled and the median number of doses administered was 15 (range, 4-31). One patient discontinued treatment due to psychosocial issues after four cycles and one contracted COVID-19 after 13 cycles. Of the 14 response-evaluable patients, 2 (14%) achieved a partial response and 10 (71%) demonstrated stable disease. Median PFS was 10.5 months (95% confidence interval: 9 months-undetermined) and 6-month PFS was 67%. Adverse events were expected and relatively mild, with one grade 3 creatinine increased, and one each of grade 3 and 4 lymphopenia. No grade 5 adverse events, unexpected toxicities, or dose-limiting toxicities were observed. Several patients reported clinical improvement in disease-related symptoms. CONCLUSIONS: High-dose pemetrexed appears tolerable and shows objective antitumor activity in patients with chordoma. Phase II studies of high-dose pemetrexed are warranted.

Activity of pemetrexed in pre-clinical chordoma models and humans.

Chordomas are rare slow growing tumors, arising from embryonic remnants of notochord with a close predilection for the axial skeleton. Recurrence is common and no effective standard medical therapy exists. Thymidylate synthase (TS), an intracellular enzyme, is a key rate-limiting enzyme of DNA biosynthesis and repair which is primarily active in proliferating and metabolically active cells. Eighty-four percent of chordoma samples had loss of TS expression which may predict response to anti-folates. Pemetrexed suppresses tumor growth by inhibiting enzymes involved in folate metabolism, resulting in decreased availability of thymidine which is necessary for DNA synthesis. Pemetrexed inhibited growth in a preclinical mouse xenograft model of human chordoma. We report three cases of metastatic chordoma that had been heavily treated previously with a variety of standard therapies with poor response. In two cases, pemetrexed was added and objective responses were observed on imaging with one patient on continuous treatment for > 2 years with continued shrinkage. One case demonstrated tumor growth after treatment with pemetrexed. The two cases which had a favorable response had a loss of TS expression, whereas the one case with progressive disease had TS present. These results demonstrate the activity of pemetrexed in recurrent chordoma and warrant a prospective clinical trial which is ongoing (NCT03955042).

Excess of blood eosinophils prior to therapy correlates with worse prognosis in mesothelioma.

Background: Only a fraction of patients with malignant pleural mesothelioma (MPM) will respond to chemo- or immunotherapy. For the majority, the condition will irremediably relapse after 13 to 18 months. In this study, we hypothesized that patients' outcome could be correlated to their immune cell profile. Focus was given to peripheral blood eosinophils that, paradoxically, can both promote or inhibit tumor growth depending on the cancer type. Methods: The characteristics of 242 patients with histologically proven MPM were retrospectively collected in three centers. Characteristics included overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and disease control rate (DCR). The mean absolute eosinophil counts (AEC) were determined by averaging AEC data sets of the last month preceding the administration of chemo- or immunotherapy. Results: An optimal cutoff of 220 eosinophils/µL of blood segregated the cohort into two groups with significantly different median OS after chemotherapy (14 and 29 months above and below the threshold, p = 0.0001). The corresponding two-year OS rates were 28% and 55% in the AEC ≥ 220/µL and AEC < 220/µL groups, respectively. Based on shorter median PFS (8 vs 17 months, p < 0.0001) and reduced DCR (55.9% vs 35.2% at 6 months), the response to standard chemotherapy was significantly affected in the AEC ≥ 220/µL subset. Similar conclusions were also drawn from data sets of patients receiving immune checkpoint-based immunotherapy. Conclusion: In conclusion, baseline AEC ≥ 220/µL preceding therapy is associated with worse outcome and quicker relapse in MPM.

The Predictive Value of ERCC1, RRM1, and Thymidylate Synthase in Advanced Malignant Pleural Mesothelioma Patients Treated with Platinum-Based Chemotherapy.

BACKGROUND: A rare yet severe neoplasia called malignant pleural mesothelioma (MPM) typically manifests itself in advanced stages. Despite some improvements in the treatment of patients with MPM, this malignancy continues to have a detrimental prognosis . The primary goal of the present study was to assess the associatin between ERCC1, RRM1, and thymidylate synthase (TS) expression and disease outcome in patients with malignant pleural mesothelioma (MPM) treated with either pemetrexed plus cisplatin or gemcitabine plus cisplatin. METHODS: This prospective cohort study was done on ninety-one advanced MPM patients. The patients received either pemetrexed plus platinum (55 of 91) or gemcitabine plus platinum chemotherapy (36 of 91). Tissue biopsy was taken at time of diagnosis. Immunohistochemistry was used to assess the levels of ERCC1, RRM1, and TS transcription in tissue biopsies (paraffin embedded). RESULTS: Based on the findings, 70% of patients with low expression of TS had low expression of ERCC1, and 68% of patients with high expression of TS had high expression of ERCC1, suggesting  a significat association between ERCC1 expression and TS expression (p=0.005). However, there was no relation between ERCC1 and RRM1 expression patterns (p= 0.296). In patients underwen platinum-based theraphy (n 91), a significant correlation was detected between low ERCC1 median High-scoring and longer progression time (TTP;9.6 v 5.3 months;P< .001) or overall survival (OS) (OS;18.1 v 9.1 months; P<0.001). A significant correlation was found between low TS protein expression and longer time progression (TTP; 11.8 v 5.4 months; P< .001) or OS (OS; 19.8 v 8.5 months; P <0.001) in patients undergoing pemetrexed plus platinum chemotherapy (n 55). Low RRM1 expression was accompanied by high progression free survival (TTP; 10.6 v 3.8 months) and OS (OS; 20.6 v 8.6 months) in patients receiving gemcitabine plus platinum chemotherapy. Based on the multivariate test results, the independent variables significantly affecting OS were tumor stage (HR: 2.3; 95% CI: 1.1-4.9; p= 0.021) and ERCC1 (HR: 2.7; 95% CI: 1.7-4.3; p < 0.001). CONCLUSION: Decreased TS protein expression can be indicative of greater responsivness to pemtrexed and of longer TTP and OS in individuals with advanced MPM (locally progressed or metastatic) who are receiving pemetrexed-based chemotheraphy. Low ERCC1 expressions in individuals with advanced MPM can predict increased PFS and OS, as well as a better responsivness to platinum-based chemotherapy. In patients with progressed MPM receiving gemcitabine plus cisplatin chemotherapy, lower RRM1 expression was associated with a better prognosis, longer PFS, and longer OS.

Thymoquinone induces apoptosis in temozolomide-resistant glioblastoma cells via the p38 mitogen-activated protein kinase signaling pathway.

Temozolomide (TMZ) can cross the blood-brain barrier (BBB) and deliver methyl groups to the purine (guanine) bases of DNA, leading to mispairing during DNA replication and subsequent cell death. However, increased expression of the repair enzyme methyl guanine methyltransferase (MGMT), which removes methyl groups from purine bases, counteracts methylation by TMZ. We evaluated the anticancer potential of thymoquinone (TQ), a hydrophobic flavonoid that inhibits resistance and induces apoptosis in various cancer cells, both in vitro and in vivo. In vitro experiments showed that compared with the Hs683 and M059J cell lines, U251 cells were more sensitive to TMZ. Compared to U251 cells, U251R cells, a TMZ drug-resistant strain established in this study, are characterized by increased expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and MGMT. TQ treatments induced apoptosis in all cell lines. The p38 mitogen-activated protein kinase signal pathway was mainly activated in U251 and U251R cells; however, p-ERK and MGMT upregulation could not suppress TQ effects. Furthermore, si-p38 pretreatment of U251R cells in TQ treatments inhibited cell apoptosis. We speculate that TQ contributed to the phosphorylation and activation of p38, but not of ERK-induced apoptosis (irrespective of TMZ resistance). In vivo, U251R-derived tumors subcutaneously inoculated in nude mice exhibited significant tumor volume reduction after TQ or TQ + TMZ cotreatments. High-performance liquid chromatography assay confirmed the presence of TQ in murine brain tissues. Our findings demonstrate that TQ can effectively cross the BBB and function alone or in combination with TMZ to treat glioblastoma.

Temozolomide: An Overview of Biological Properties, Drug Delivery Nanosystems, and Analytical Methods.

Temozolomide (TMZ) is an imidazotetrazine prodrug used to treat glioblastoma multiforme. Its physicochemical properties and small size confer the ability to cross the blood-brain barrier. The antitumor activity depends on pH-dependent hydrolysis of the methyldiazonium cation, which is capable of methylating purine bases (O6-guanine; N7-guanine, and N3-adenine) and causing DNA damage and cell death. TMZ is more stable in acidic media (pH ≤ 5.0) than in basic media (pH ≥ 7.0) due to the protonated form that minimizes the catalytic process. Due to this, TMZ has high oral bioavailability, but it has a half-life of 1.8 h and low brain distribution (17.8%), requiring a repeated dosing regimen that limits its efficacy and increases adverse events. Drug delivery Nanosystems (DDNs) improve the physicochemical properties of TMZ and may provide controlled and targeted delivery. Therefore, DDNs can increase the efficacy and safety of TMZ. In this context, to ensure the efficiency of DDNs, analytical methods are used to evaluate TMZ pharmacokinetic parameters, encapsulation efficiency, and the release profile of DDNs. Among the methods, high-performance liquid chromatography is the most used due to its detection sensitivity in complex matrices such as tissues and plasma. Micellar electrokinetic chromatography features fast analysis and no sample pretreatment. Spectrophotometric methods are still used to determine encapsulation efficiency due to their low cost, despite their low sensitivity. This review summarizes the physicochemical and pharmacological properties of free TMZ and TMZ-loaded DDNs. In addition, this review addresses the main analytical methods employed to characterize TMZ in different matrices.

Risk of hepatocellular carcinoma in antiviral treatment-naïve chronic hepatitis B patients treated with entecavir or tenofovir disoproxil fumarate: a network meta-analysis.

BACKGROUND: Long-term antiviral treatments are associated with a significantly lower hepatocellular carcinoma (HCC) incidence in chronic hepatitis B (CHB) patients by reducing HBV DNA concentrations. However, it is still controversial whether antiviral strategies affect HCC development in antiviral treatment-naïve CHB patients. This study aimed to estimate the incidence of HCC in antiviral treatment-naïve CHB patients who were treated with Entecavir (ETV) and Tenofovir Disoproxil Fumarate (TDF) and compare the efficacy of two treatment regimens in HCC reduction. METHODS: The PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases were systematically searched until June 24, 2021. The pooled incidence and 95% confidence interval of HCC were calculated by the Freeman-Tukey double arcsine transformation method. The efficacies of ETV and TDF treatments in HCC reduction were compared through a network meta-analysis. RESULTS: A total of 27 studies were identified as eligible for this systematic review. The incidence densities in the ETV and TDF treatment groups were 2.78 (95% CI: 2.21-3.40) and 2.59 (95% CI: 1.51-3.96) per 100 persons-year among patients with preexisting cirrhosis and 0.49 (95% CI: 0.32-0.68) and 0.30 (95% CI: 0.06-0.70) per 100 persons-year among patients without preexisting cirrhosis. As the proportion of CHB patients with preexisting cirrhosis increased, the incidence density of HCC also increased gradually. Compared with other Nucleos(t)ide analogs (NAs) treatments, ETV and TDF treatments significantly lowered the risk of HCC, with hazard ratios (HRs) of 0.60 (95% CI: 0.40-0.90) and 0.56 (95% CI: 0.35-0.89), respectively. However, there was no difference in the incidence density of HCC between ETV and TDF treatments (HR = 0.92, 95% CI: 0.71-1.20) regardless of preexisting cirrhosis. CONCLUSION: ETV and TDF treatments were associated with significantly lower risks of HCC than other NAs treatments. However, no difference was observed between ETV and TDF treatments in the risk of HCC development regardless of preexisting cirrhosis among treatment-naïve CHB patients.

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

BACKGROUND: To evaluate the long-term efficacy of switching of the nucleos(t)ide analog used for treatment from entecavir (ETV) to tenofovir alafenamide fumarate (TAF) in patients with chronic HBV infection. METHODS: A total of 103 patients with serum HBsAg levels of ≥100 IU/mL who had received ETV were enrolled. The nucleos(t)ide analog used for the treatment was switched from ETV to TAF, and the changes in serum HBsAg levels during the 144-week period before and after the drug switching were compared in 74 patients who had received ETV at least for 192 weeks. RESULTS: Significant decreases of serum HBsAg levels were observed during both the ETV and the TAF administration period, although the degree of reduction was greater during the latter period than during the former period (P<0.001). Significant decreases of serum HBsAg levels were seen in both patients with genotype B HBV infection and genotype C HBV infection, irrespective of the serum HBsAg and HBcrAg levels at the time of the drug switching. CONCLUSION: Switching of the nucleos(t)ide analog used for treatment from ETV to TAF merits consideration in patients with chronic HBV infection, since the extent of reduction of the serum HBsAg level was greater during the TAF treatment period than during the ETV treatment period.

Current Trend in Antiviral Therapy for Chronic Hepatitis B.

Since active hepatitis B virus (HBV) replication is the key driver of hepatic necroinflammation and disease progression, the treatment aim of chronic hepatitis B (CHB) is to suppress HBV replication permanently to prevent hepatic decompensation, liver cirrhosis and/or hepatocellular carcinoma and prolong survival. Currently, pegylated interferon (Peg-IFN), entecavir (ETV), tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF) are the first-line drugs of choice. Peg-IFN therapy has been used rarely due to its subcutaneous injection and significant side effect profile. Once daily oral ETV, TDF and TAF can suppress HBV DNA profoundly but have no direct action on cccDNA of the HBV-infected hepatocytes, hence continuing long-term therapy is usually needed to maintain HBV suppression, but the ultimate goal of HBsAg loss was rarely achieved (10 year 2%). In addition, long-term NUC therapy comes with several concerns such as increasing cost, medication adherence and loss-to-follow-up. Studies, mainly from Taiwan, have shown that finite NUCs therapy of two to three years in HBeAg-negative patients is feasible, safe and has a great benefit of much increasing HBsAg loss rate up to 30%/5 year. These have led an emerging paradigm shift to finite NUC therapy in HBeAg-negative patients globally. However, off-NUC relapse with hepatitis B flares may occur and have a risk of decompensation or even life-threatening outcomes. Therefore, proper monitoring, assessment, and retreatment decisions are crucial to ensure safety. Ideally, retreatment should be not too late to ensure safety and also not too early to allow further immune response for further HBsAg decline toward HBsAg loss. Assessment using combined HBsAg/ALT kinetics during hepatitis flare is better than biochemical markers alone to make a right retreatment decision. The strategy of finite NUC therapy has set a benchmark of high HBsAg loss rate to be achieved by the new anti-HBV drugs which are under preclinical or early phase study.

Effectiveness of prophylactic antiviral therapy in reducing HBV reactivation for HBsAg-positive recipients following allogeneic hematopoietic stem cell transplantation: a multi-institutional experience from an HBV endemic area.

Hepatitis B virus reactivation (HBVr) is not uncommon in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Hepatitis B surface antigen (HBsAg)-positive patients receiving allo-HSCT have a very high risk of HBVr. However, the validity of prophylactic antiviral treatment in HBsAg-positive allo-HSCT recipients has not been well studied. We aimed to add experience in dealing with HBsAg-positive patients following allo-HSCT. We conducted a cohort study that included 11 years of data of HBsAg-positive allo-HSCT patients in multiple centers. The cumulative incidence of HBVr with antiviral prophylaxis at 60 months following transplantation was 8.9%. Both lamivudine (LAM) and entecavir (ETV) effectively reduced the incidence of HBVr. Patients with absent-mild cGVHD had a lower HBVr rate than that of patients with moderate-severe cGVHD (HR = 0.201, P = 0.020). The incidence of HBsAg seroclearance at 60 months following transplantation was 34.3%. Recipients accepting from anti-HBs-negative donors were associated with a lower HBsAg seroclearance rate than that of those accepting from anti-HBs-positive donors (HR=0.255, P < 0.001). The peripheral blood stem cell (PBSC) donor source had a higher HBsAg seroclearance rates than that of the PBSC plus bone marrow stem cell source (HR = 4.700, P = 0.047). The prophylactic antiviral treatment effectively reduced HBVr in HBsAg-positive recipients receiving allo-HSCT. HBsAg-positive recipients accept anti-HBs-positive PBSC donor sources may facilitate the acquisition of HBsAg seroclearance after transplantation.

Soluble programmed cell death-1 predicts hepatocellular carcinoma development during nucleoside analogue treatment.

Soluble immune checkpoint molecules are emerging novel mediators of immune regulation. However, it is unclear whether soluble immune checkpoint proteins affect the development of hepatocellular carcinoma (HCC) during nucleos(t)ide analogue (NA) treatment in patients with chronic hepatitis B virus infection. This study included 122 NA-naïve patients who received NA therapy. We assessed the associations of clinical factors, including soluble immune checkpoint proteins, with HCC development during NA treatment. The baseline serum concentrations of 16 soluble immune checkpoint proteins were measured using multiplexed fluorescent bead-based immunoassay. In total, 13 patients developed HCC during the follow-up period (median duration, 4.3 years). Of the 16 proteins, soluble inducible T-cell co-stimulator (≥ 164.71 pg/mL; p = 0.014), soluble programmed cell death-1 (sPD-1) (≤ 447.27 pg/mL; p = 0.031), soluble CD40 (≤ 493.68 pg/mL; p = 0.032), and soluble herpes virus entry mediator (≤ 2470.83 pg/mL; p = 0.038) were significantly associated with HCC development (log-rank test). In multivariate analysis, an sPD-1 level ≤ 447.27 pg/mL (p = 0.014; hazard ratio [HR], 4.537) and α-fetoprotein level ≥ 6.4 ng/mL (p = 0.040; HR, 5.524) were independently and significantly associated with HCC development. Pre-treatment sPD-1 is a novel predictive biomarker for HCC development during NA treatment.

Variability in the Responses of Hepatitis B Virus D-Subgenotypes to Antiviral Therapy: Designing Pan-D-Subgenotypic Reverse Transcriptase Inhibitors.

Nucleos(t)ide analogues entecavir (ETV) and tenofovir disoproxil fumarate (TDF) are recommended as first-line monotherapies for chronic hepatitis B (CHB). Multiple HBV genotypes/subgenotypes have been described, but their impact on treatment response remains largely elusive. We investigated the effectiveness of ETV/TDF on HBV/D-subgenotypes, D1/D2/D3/D5, studied the structural/functional differences in subgenotype-specific reverse transcriptase (RT) domains of viral polymerase, and identified novel molecules with robust inhibitory activity on various D-subgenotypes. Transfection of Huh7 cells with full-length D1/D2/D3/D5 and in vitro TDF/ETV susceptibility assays demonstrated that D1/D2 had greater susceptibility to TDF/ETV while D3/D5 exhibited poorer response. Additionally, HBV load was substantially reduced in TDF-treated CHB patients carrying D1/D2 but minimally reduced in D3/D5-infected patients. Comparison of RT sequences of D-subgenotypes led to identification of unique subgenotype-specific residues, and molecular modeling/docking/simulation studies depicted differential bindings of TDF/ETV to the active site of their respective RTs. Replacement of signature residues in D3/D5 HBV clones with corresponding amino acids seen in D1/D2 improved their susceptibility to TDF/ETV. Using high throughput virtual screening, we identified N(9)-[3-fluoro-2-(phosphonomethoxy)propyl] (FPMP) derivatives of purine bases, including N6-substituted (S)-FPMP derivative of 2,6-diaminopurine (DAP) (OB-123-VK), as potential binders of RT of different D-subgenotypes. We synthesized (S)-FPMPG prodrugs (FK-381-FEE/FK-381-SEE/FK-382) and tested their effectiveness along with OB-123-VK. Both OB-123-VK and FK-381-FEE exerted similar antiviral activities against all D-subgenotypes, although FK-381-FEE was more potent. Our study highlighted the natural variation in therapeutic response of D1/D2/D3/D5 and emphasized the need for HBV subgenotype determination before treatment. Novel molecules described here could benefit future design/discovery of pan-D-subgenotypic inhibitors. IMPORTANCE Current treatment of chronic hepatitis B relies heavily on nucleotide/nucleoside analogs in particular, tenofovir disoproxil fumarate (TDF) and entecavir (ETV) to keep HBV replication under control and prevent end-stage liver diseases. However, it was unclear whether the therapeutic effects of TDF/ETV differ among patients infected with different HBV genotypes and subgenotypes. HBV genotype D is the most widespread of all HBV genotypes and multiple D-subgenotypes have been described. We here report that different subgenotypes of HBV genotype-D exhibit variable response toward TDF and ETV and this could be attributed to naturally occurring amino acid changes in the reverse transcriptase domain of the subgenotype-specific polymerase. Further, we identified novel molecules and also synthesized prodrugs that are equally effective on different D-subgenotypes and could facilitate management of HBV/D-infected patients irrespective of D-subgenotype.