The bioavailability time of commonly used thymidine analogues after intraperitoneal delivery in mice: labeling kinetics in vivo and clearance from blood serum.

Detection of synthetic thymidine analogues after their incorporation into replicating DNA during the S-phase of the cell cycle is a widely exploited methodology for evaluating proliferative activity, tracing dividing and post-mitotic cells, and determining cell-cycle parameters both in vitro and in vivo. To produce valid quantitative readouts for in vivo experiments with single intraperitoneal delivery of a particular nucleotide, it is necessary to determine the time interval during which a synthetic thymidine analogue can be incorporated into newly synthesized DNA, and the time by which the nucleotide is cleared from the blood serum. To date, using a variety of methods, only the bioavailability time of tritiated thymidine and 5-bromo-2'-deoxyuridine (BrdU) have been evaluated. Recent advances in double- and triple-S-phase labeling using 5-iodo-2'-deoxyuridine (IdU), 5-chloro-2'-deoxyuridine (CldU), and 5-ethynyl-2'-deoxyuridine (EdU) have raised the question of the bioavailability time of these modified nucleotides. Here, we examined their labeling kinetics in vivo and evaluated label clearance from blood serum after single intraperitoneal delivery to mice at doses equimolar to the saturation dose of BrdU (150 mg/kg). We found that under these conditions, all the examined thymidine analogues exhibit similar labeling kinetics and clearance rates from the blood serum. Our results indicate that all thymidine analogues delivered at the indicated doses have similar bioavailability times (approximately 1 h). Our findings are significant for the practical use of multiple S-phase labeling with any combinations of BrdU, IdU, CldU, and EdU and for obtaining valid labeling readouts.

Effects of entecavir, tenofovir and telbivudine treatment on renal functions in chronic hepatitis B patients.

BACKGROUND AND STUDY AIMS: The aim of this study was to enlighten the controversy about the renal safety of entecavir, tenofovir, and telbivudine treatments in chronic hepatitis B (CHB) patients by comparing these treatments in real-world conditions. PATIENTS AND METHODS: We retrospectively enrolled 104 treatment-naive patients with CHB monoinfection into our study. Patients were treated with entecavir monotherapy (n=38), tenofovir monotherapy (n=35), or telbivudine monotherapy (n=31). We then compared and statistically analyzed the effects of these drugs on the estimated glomerular filtration rate (eGFR) over a 24-month follow-up period. RESULTS: In the entecavir group, time-dependent change in eGFR was not statistically significant (p = 0.357). There was a statistically significant increase in eGFR in the telbivudine group at 12 months (p<0.001) and at 24 months (p<0.001) and, in contrast, a statistically significant decrease in the tenofovir group at 12 months (p<0.001) and at 24 months (p<0.001). There was no significant relationship between entecavir and eGFR change (p = 0.763). We found that tenofovir and telbivudine were independent predictors of eGFR change (decrease in eGFR, p<0.001 and increase in eGFR, p = 0.001, respectively). CONCLUSIONS: We recommend close follow-up of renal functions, especially for patients treated with tenofovir. Telbivudine was superior to the other drugs in terms of renal function. We conclude that an individualized therapy program considering treatment efficacy and side effects is the best option for patients.

Prior exposure to thymidine analogs and didanosine is associated with long-lasting alterations in adipose tissue distribution and cardiovascular risk factors.

BACKGROUND: Thymidine analogs and didanosine (ddI) have been associated with redistribution of body fat from subcutaneous adipose tissue (SAT) to visceral adipose tissue (VAT), which, in turn, is a risk factor for cardiovascular disease. We explored differences in adipose tissue distribution between people living with HIV (PLWH) with prior exposure to thymidine analogs and/or ddI, without exposure, and uninfected controls and the association with cardiovascular disease risk factors. METHODS: In all, 761 PLWH from the Copenhagen Comorbidity in HIV Infection study, and 2283 age and sex-matched uninfected controls from the Copenhagen General Population Study were included. PLWH were stratified according to prior exposure to thymidine analogs and/or ddI. VAT and SAT were determined by abdominal computed tomography scan. Hypotheses were tested using regression analyses. RESULTS: Exposure to thymidine analogs and/or ddI was associated with 21.6 cm larger VAT (13.8-29.3) compared to HIV infection without exposure. HIV-negative status was associated with similar VAT compared to HIV infection without exposure. Cumulative exposure to thymidine analogs and/or ddI [3.7 cm per year (2.3-5.1)], but not time since discontinuation [-1.1 cm per year (-3.4 to 1.1)], was associated with VAT. Prior exposure to thymidine analogs and/or ddI was associated with excess risk of hypertension [adjusted odds ratio (aOR) 1.62 (1.13-2.31)], hypercholesterolemia [aOR 1.49 (1.06-2.11)], and low high-density lipoprotein [aOR 1.40 (0.99-1.99)]. CONCLUSIONS: This study suggests a potentially irreversible and harmful association of thymidine analogs and ddI with VAT accumulation, which appears be involved in the increased risk of hypertension, hypercholesterolemia, and low high-density lipoprotein found in PLWH with prior exposure to thymidine analogs and/or ddI, even years after treatment discontinuation.

Effectiveness of telbivudine antiviral treatment in patients with hepatitis B virus-associated glomerulonephritis: A 104-week pilot study.

The aim of this study was to evaluate clinical efficacy of telbivudine in treatment of hepatitis B virus-associated glomerulonephritis (HBV-GN).A total of 43 HBV-GN patients combined with chronic hepatitis B were treated with telbivudine for 104 weeks. Serum levels of HBV DNA viral load, HBeAg, HBeAb, alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum creatinine (Cr), and 24-hour urinary protein were evaluated after telbivudine treatment of 12, 24, 52, 76, and 104 weeks. Estimated glomerular filtration rate (eGFR) was calculated at baseline, 24 weeks, 52 weeks, and 104 weeks of treatment, respectively. Complete remission (CR) was defined as urinary protein <0.3 g/day, with normal ALT, AST, Cr, and eGFR. Criteria for partial remission include: 24-hour urinary protein excretion decreased by >50% compared with baseline level, and ALT and AST decreased >50%.Proteinuria level gradually decreased in patients with HBV-GN after telbivudine treatment. The percentages of PR + CR were 90.7% and 95.3%, respectively, at 52 and 104 weeks. Compared to baseline, eGFR were significantly increased from 69.2 ±â€Š23.1 mL/min/1.73 m to 116.2 ±â€Š26.3 mL/min/1.73 m at 104 weeks of treatment. Multivariate analysis indicated that baseline HBV DNA viral load (odds ratio [OR] = 1.19, 95% confidence interval [CI] 1.11-2.19, P = .02) and baseline urinary protein (OR = 1.08, 95% CI 1.04-2.44, P = .03) were independent risk factors associated with CR after telbivudine treatment among patients with HBV-GN.Our study demonstrates that telbivudine can be used to treat HBV-GN and effectively improve eGFR in these patients.

Increase of Serum Kallikrein-8 Level After Long-term Telbivudine Treatment.

BACKGROUND/AIM: Our previous cDNA microarray study revealed increased cellular mRNA levels of a panel of genes, including kallikrein-8 (KLK8), after long-term telbivudine treatment in chronic hepatitis B patients. The aim of this study was to verify whether serum protein levels of KLK8, a cancer-related enzyme, are indeed increased after telbivudine treatment. PATIENTS AND METHODS: A total of 83 chronic hepatitis B patients receiving telbivudine for >2 years were retrospectively analyzed. Serum KLK8 protein and estimated glomerular filtration rate (eGFR) changes were compared before and after treatment. RESULTS: Both serum KLK8 protein and eGFR increased significantly after long-term telbivudine treatment (paired t-test: KLK8, p<0.001; eGFR, p=0.001). No direct correlation was found between KLK8 increase and eGFR change. However, eGFR change was positively associated with post-treatment KLK8 levels following adjustment for body height (p<0.001). CONCLUSION: Telbivudine treatment resulted in increased levels of serum KLK8 protein. Furthermore, eGFR increase was associated with body height-adjusted, post-treatment KLK8 levels.

Determination of telbivudine in the plasma of chronic hepatitis B patients in long-term treatment by high-performance liquid chromatographic-tandem mass spectrometry.

Creatine kinase elevation is commonly reported in telbivudine-treated patients. However, little is known about the relationship between this adverse drug reaction and plasma concentration. In this study, a sensitive, rapid and safe quantitative bioanalytical method has been established by using LC-MS/MS for the determination of telbivudine in a clinical study of chronic hepatitis B patients. The assay was linear in a dynamic 10-10,000 ng/mL range (r2 > 0.999) and total analysis time was 6 min in this method. The validated method was applied to quantitatively determine plasma concentration in chronic hepatitis B patients during long-term telbivudine treatment. The results revealed that telbivudine concentration in the creatine kinase-elevated group (707.92-2788.78 ng/mL) was significantly higher than those with normal creatine kinase (412.63-1108.32 ng/mL). This method was adapted for therapeutic drug monitoring.

Rhabdomyolysis, lactic acidosis, and multiple organ failure during telbivudine treatment for hepatitis B: a case report and review of the literature.

BACKGROUND: Telbivudine can cause severe side effects, including myositis, neuritis, rhabdomyolysis, and lactic acidosis. However, reported cases of telbivudine leading to multiple organ failure are rare. Here, we report a case of telbivudine-induced severe polymyositis, lactic acidosis, and multiple organ failure. CASE PRESENTATION: A 30-year-old Chinese man with hepatitis B virus infection received antiviral treatment with 600 mg of telbivudine daily for more than 11 months. He developed progressive weakness and myalgia, and subsequently experienced palpitations, chest tightness, lethargy, hypotension, and hypoxemia. Blood tests showed markedly elevated levels of alanine aminotransferase (955 U/L), aspartate aminotransferase (1375 U/L), blood urea nitrogen (14.9 mmol/L), creatine kinase (peak at 8050 U/L), and blood lactate (>20.0 mmol/L). His symptoms improved after continuous renal replacement therapy and short-term methylprednisolone treatment. Hyperbaric oxygen therapy, physical therapy, and rehabilitation for more than 2 months led to recovery of muscle strength to the normal range. CONCLUSIONS: We conclude that continuous renal replacement and steroid therapies play key roles in stabilizing telbivudine-induced severe rhabdomyolysis, lactic acidosis, and multiple organ failure. Hyperbaric oxygen, physical therapy, and rehabilitation may aid in functional recovery after the acute phase of lactic acidosis and organ failure.

Safety and efficacy of telbivudine for chronic hepatitis B during the entire pregnancy: Long-term follow-up.

The management of hepatitis B virus (HBV) infection in pregnancy is a unique issue. Telbivudine (LdT) is recommended to block HBV mother-to-child transmission (MTCT) in the third trimester. However, the safety of LdT treatment during the entire pregnancy for the long-term growth of infants is unclear. The aim of this study was to evaluate the efficacy and long-term safety of LdT for the entire pregnancy period. This retrospective cohort study included 40 pregnant women and 43 children from 2011 to 2017. The antiviral effects and maternal abnormalities were evaluated. In addition, adverse events regarding infants at delivery and HBV vaccination outcomes were recorded. The status of physical development in the children during follow-up was also evaluated. Among pregnant women, the rates of HBV DNA flare were 5.00% during pregnancy and 7.50% postpartum, and the HBeAg seroconversion rates were 7.50% during pregnancy and 7.50% postpartum. No severe maternal abnormalities were observed. Regarding the infants, no one was positive for HBsAg, and only one infant was negative for anti-HBs in children over 7 months of age. Furthermore, no birth defects or severe adverse events were observed at delivery, and 97.67% normal height and 93.02% normal weight in children were observed on follow-up until 5 years of age. In conclusion, LdT use for the entire pregnancy is both effective for treating pregnant women and blocking HBV MTCT. Moreover, LdT is safe for women and infants. Most importantly, the long-term follow-up indicated that LdT is safe and does not affect the growth of children.

Prospective cohort study on the efficacy and safety of telbivudine used throughout pregnancy in blocking mother-to-child transmission of hepatitis B virus.

Women with chronic hepatitis B should maintain nucleotide analogue treatment to prevent disease progression during pregnancy. The aim of this study was to prospectively evaluate the efficacy and safety of telbivudine used throughout pregnancy for preventing hepatitis B virus (HBV) mother-to-child transmission (MTCT). From January 2012 to June 2014, women who were receiving telbivudine therapy and became pregnant were enrolled in group A at 28 weeks of gestation. Pregnant women with an HBV DNA level >106  IU/mL were enrolled in either group B (telbivudine started at 28 weeks of gestation) or group C (control group without treatment). MTCT was defined as infants who were positive for serum hepatitis B surface antigen at 7 months after birth. There were 41, 179 and 177 pregnant women (397 infants) enrolled in groups A, B and C, respectively. The HBV DNA load at 28 weeks of gestation and delivery was 1.50 ± 0.62 vs 1.45 ± 0.61, 8.05 ± 0.37 vs 4.24 ± 0.89 and 7.94 ± 0.62 vs 7.86 ± 0.73 log10 IU/mL in groups A, B and C, respectively. The rate of MTCT in group C was 4.60%, which was significantly higher than the rates in groups A and B (0% and 0.6%, respectively) (P = .043). The difference between group A and group B was not significant. The rates of neonatal congenital abnormalities were 2.4%, 0.6% and 2.3% in groups A, B and C, respectively, and there were no significant differences (P = .140). Telbivudine used throughout pregnancy may be safe and effective for mothers and infants, but it may not enhance the efficacy of an HBV MTCT block compared with treatment starting at 28 weeks of gestation (NCT02253485).

Comparison of 208-week sequential therapy with telbivudine and entecavir in HBeAg-positive chronic hepatitis B patients with suboptimal responses to 24 weeks of Peg-IFNα-2a therapy: An open-labelled, randomized, controlled, "real-life" trial.

The purpose of the study was to compare the efficacy and safety of 208-week sequential therapy with telbivudine and entecavir in HBeAg-positive chronic hepatitis B (CHB) patients with suboptimal responses to 24 weeks of Peg-IFNα-2a therapy. This was an open-label, randomized, controlled, "real-life" trial. HBeAg-positive CHB patients with serum HBV DNA ≥5.0 lg IU/mL and a < 1 lg IU/mL decline of HBsAg level from baseline who underwent at least 24 weeks of Peg-IFNα-2a therapy were included. Enrolled patients were randomized to receive either telbivudine (600 mg/d, n = 95) or entecavir (0.5 mg/d, n = 95) for 208 consecutive weeks. Six patients were lost to follow-up (4 patients in the telbivudine group and 2 in the entecavir group). Treatment was combined with adefovir when week 24 HBV DNA levels declined to <2 lg IU/mL versus baseline, when viral breakthrough occurred during treatment,or when HBV DNA remained detectable at 52 weeks (HBV DNA ≥500 IU/mL). Responses and safety were assessed after 208 weeks of treatment. There were no significant differences among the baseline characteristics, including age, gender, and ALT, HBV DNA, HBsAg or HBeAg levels. After 208 weeks of treatment, there was no significant difference in the rates of undetectable HBV DNA (HBV DNA<500 IU/mL) between the telbivudine group and the entecavir group (84/91,92.31% vs 88/93,94.62%, respectively, P = .525). More patients in the telbivudine group than the entecavir group achieved HBeAg clearance (74.73% vs 46.24%, respectively, P < .001) and HBeAg seroconversion (64.84% vs 38.71%, respectively, P < .001). Univariate analysis (Enter, a = 0.05) of both groups showed that telbivudine, male gender and baseline HBeAg levels were significantly correlated with HBeAg seroconversion after 208 weeks of sequential therapy. Cox regression analysis (Enter, a = 0.05) of the telbivudine group showed that the HBeAg seroconversion rate at 208 weeks was significantly correlated with gender (male) (P = .006, HR=4.406), baseline HBeAg level (P = .005, HR=0.433) and 24 w-HBeAg level reduction of more than 0.5 lg IU/ml from baseline (P = .027, HR=0.487). All patients tolerated sequential telbivudine treatment; only slightly elevated creatine kinase levels were observed. Stratification analysis found that patients with baseline HBeAg levels less than 3 lg COI who switched to telbivudine may have had significantly improved HBeAg seroconversion rates. In conclusion, telbivudine promotes HBeAg seroconversion that merits investigation in HBeAg-positive CHB patients with suboptimal responses to 24 weeks of Peg-IFNα-2a therapy. We would suggest that patients with baseline HBeAg levels under 3 lg COI switch to telbivudine to achieve higher HBeAg seroconversion rates and use the early reductions in HBeAg levels (24 weeks) to guide treatment.

Long-term outcome of telbivudine versus entecavir in treating higher viral load chronic hepatitis B patients without cirrhosis.

Chronic hepatitis B (CHB) patients with higher hepatitis B virus (HBV) load (higher viral load [HVL], HBV DNA ≥1 × 107 copies/mL) require antiviral therapy, but data for evaluating the long-term outcome of this therapy with antiviral agents remain limited. We comparatively evaluated the efficacy and the safety of nucleoside analogues in 179 noncirrhotic CHB patients with HVL over 5 years. The HBeAg-positive (n = 104) or HBeAg-negative (n = 75) patients were treated consecutively with telbivudine (LdT, n = 88) or entecavir (ETV, n = 91) and evaluated for viral response, drug resistance and safety. HBV DNA, viral serology, biochemistries, HBV mutation and off-therapy relapse were determined. The cumulative rates of HBV DNA negativity were 86.4% and 94.5% for LdT and ETV at year 5, respectively. The rates of early viral response (EVR, HBV DNA <103 copies/mL at month 6) under LdT and ETV treatments were 58.0% and 34.1%, respectively (P < .05). Hepatitis B e antigen (HBeAg) and Hepatitis B surface antigen (HBsAg) loss-seroconversions were 47.7% and 18.2% on LdT and 16.5% and 2.2% on ETV (P < .01). Eighteen patients (age 28.2 ± 3.1) experienced HBsAg loss-seroconversion, followed by 33 ± 4.6 month off-therapy without a relapse. Viral mutations and serum creatine kinase elevation were 9.1% and 8.0% on LdT, but only 1.1% and 0% on ETV. Both LdT and ETV suppressed HBV replication in HVL CHB patients within 5 years. LdT therapy achieved a higher EVR, HBeAg and HBsAg seroconversion, especially in the younger patients, whereas ETV caused lower drug resistance and fewer adverse events. This finding might help to identify the optimal treatment for CHB patients with HVL.

Telbivudine therapy for gravidas with chronic hepatitis B infection and patients at risk of renal impairment.

Hepatitis B virus infection is currently the most important cause of chronic viral hepatitis worldwide and is one of the most frequent causes of end-stage liver disease. With the international implementation of the hepatitis B vaccine and combined prophylaxis for infants born to HBsAg(+) mothers, the prevalence of hepatitis B has decreased remarkably. However, intra-uterine transmission has become a critical bottleneck for eliminating hepatitis B infection. The efficacy of nucleos(t)ide analogs on inhibiting hepatitis B replication has been widely confirmed, and the quality of life and the survival of individuals with chronic hepatitis B (CHB) have improved to a great degree. However, with the availability of long-term antiviral treatment and the ever increasing ageing population, renal disorders should be considered when choosing antiviral medicines. The antiviral efficacy and safety of telbivudine (LdT) have been shown in patients with CHB infection, and LdT is approved as a class B drug for pregnancy. Furthermore, the renal protective function of LdT has been demonstrated recently. In this review, we will focus on the efficacy and safety of LdT in gravidas with CHB infection, as well as the renal protective function of LdT in CHB patients. LdT might provide physicians with a solid option for effectively treating patients with CHB, especially gravidas or those either with or at risk of renal impairment.

Renal Function Improvement by Telbivudine in Liver Transplant Recipients with Chronic Kidney Disease.

Chronic renal failure is a frequent complication in liver transplantation. Telbivudine, anti-hepatitis B virus (HBV) nucleoside, can improve renal function. It is interesting if using telbivudine for prophylaxis of HBV recurrence has additional value on renal function improvement. 120 liver transplant recipients with lamivudine prophylaxis for HBV recurrence were 1 : 1 randomized into lamivudine-continuous (n = 60) and telbivudine-replacement (n = 60) groups. Fifty-eight patients in lamivudine-continuous group and 54 in telbivudine-replacement group completed the study. In telbivudine-replacement group, the estimated glomerular filtration rate (eGRF) was improved from 63.0 ± 16.3 ml/min to 72.8 ± 21.1 ml/min at 12 months after telbivudine administration (p = 0.003). Stratifying the patients according to renal function staging, the eGRF was improved from 74.7 ± 6.9 ml/min to 84.2 ± 16.6 ml/min (p = 0.002) in 32 stage II patients and from 48.2 ± 7.3 ml/min to 59.7 ± 11.8 ml/min in 20 stage III patients after 12 months of telbivudine administration (p < 0.001). Eleven (18.3%) patients with telbivudine developed polyneuritis during the trial and post hoc following-up. In conclusion, renal function was improved by telbivudine in liver transplant recipients with long-term chronic kidney disease. However, the high incidence of polyneuritis induced by telbivudine has to be closely monitored. This trial is registered with ClinicalTrials NCT02447705.

Combination Therapy for Chronic Hepatitis B: Current Updates and Perspectives.

Nucleos(t)ide analogues (NUCs) and interferon have been used for several decades to treat chronic hepatitis B; however, the therapeutic response remains unsatisfactory. Although NUC therapy exhibits potent on-treatment viral suppression, frequent off-therapy virological relapses suggest an indefinite treatment course. Interferon modulates the innate and adaptive antiviral immune responses and thus increases the chance of viral eradication. Interferon therapy has the advantage of a finite duration, absence of drug resistance, and durable posttreatment responses. Therefore, the combination of NUCs and interferon can theoretically facilitate a synergistic therapeutic effect. This paper summarizes the current strategies of various combination therapies into three categories: the simultaneous "dual" strategy, sequential combination "add-on" strategy, and "switch" strategy. Generally, dual therapy exhibits greater on-treatment and off-therapy viral suppression and lower drug resistance compared with NUC monotherapy. Compared with interferon monotherapy, dual therapy has greater on-treatment viral suppression but shows no difference in off-therapy sustained virological responses. Specific add-on or switch strategies provide promising on-treatment efficacy in select patients. Pretreatment or on-treatment quantitative hepatitis B surface antigen and e antigen are predictive for the treatment efficacy of combination therapy. The optimal schedule of combination regimens and individualized therapy remain to be comprehensively evaluated.

Deoxycytidine and Deoxythymidine Treatment for Thymidine Kinase 2 Deficiency.

OBJECTIVE: Thymidine kinase 2 (TK2), a critical enzyme in the mitochondrial pyrimidine salvage pathway, is essential for mitochondrial DNA (mtDNA) maintenance. Mutations in the nuclear gene, TK2, cause TK2 deficiency, which manifests predominantly in children as myopathy with mtDNA depletion. Molecular bypass therapy with the TK2 products, deoxycytidine monophosphate (dCMP) and deoxythymidine monophosphate (dTMP), prolongs the life span of Tk2-deficient (Tk2-/- ) mice by 2- to 3-fold. Because we observed rapid catabolism of the deoxynucleoside monophosphates to deoxythymidine (dT) and deoxycytidine (dC), we hypothesized that: (1) deoxynucleosides might be the major active agents and (2) inhibition of deoxycytidine deamination might enhance dTMP+dCMP therapy. METHODS: To test these hypotheses, we assessed two therapies in Tk2-/- mice: (1) dT+dC and (2) coadministration of the deaminase inhibitor, tetrahydrouridine (THU), with dTMP+dCMP. RESULTS: We observed that dC+dT delayed disease onset, prolonged life span of Tk2-deficient mice and restored mtDNA copy number as well as respiratory chain enzyme activities and levels. In contrast, dCMP+dTMP+THU therapy decreased life span of Tk2-/- animals compared to dCMP+dTMP. INTERPRETATION: Our studies demonstrate that deoxynucleoside substrate enhancement is a novel therapy, which may ameliorate TK2 deficiency in patients. Ann Neurol 2017;81:641-652.

Telbivudine therapy for chronic hepatitis B: A journey to identify super-responders and to optimize treatment using the roadmap model.

Hepatitis B virus (HBV) infection is one of the most serious health problems worldwide with a high risk for cirrhosis and liver cancer. Several antiviral agents have been approved for the treatment of chronic hepatitis B, leading to a rapid reduction in HBV DNA and normalization of serum alanine aminotransferase levels. Telbivudine, a potent inhibitor of HBV replication, has been shown to be well tolerated. Because of the emergence of drug resistance, optimization strategies for telbivudine therapy have been shown to improve patient responses. Optimal baseline characteristics in so-called super-responders have been used to predict the virological response. Baseline HBV DNA levels < 9 log10 copies/mL (2 × 108 IU/mL) or alanine aminotransferase levels of more than or equal to twofold the upper limit of normal in HBeAg-positive patients and HBV DNA < 7 log10 copies/mL (2 × 106 IU/mL) in HBeAg-negative patients were strong predictors for virological response. In addition, the roadmap model, based on early virological response at week 24 of therapy, is considered as a powerful tool to identify patients at risk of treatment failure (HBV DNA ≥ 300 copies/mL, i.e. 60 IU/mL) and to reduce the risk of antiviral resistance. When considering pre-treatment characteristics and on-treatment responses, telbivudine may provide physicians with a wide choice of options to effectively treat patients with chronic hepatitis B, especially those with or at risk of renal impairment, or women of childbearing age.

Reduction of covalently closed circular DNA with long-term nucleos(t)ide analogue treatment in chronic hepatitis B.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), a mini-chromosome essential for HBV replication, is supposed to be resistant to nucleos(t)ide analogue treatment. We investigated the effect of long-term nucleos(t)ide analogue treatment on cccDNA. METHODS: Among 129 patients who had been enrolled in previous international nucleos(t)ide analogue clinical trials and had liver biopsies at baseline and one year after treatment, we recruited 43 patients on long-term continuous treatment for 72 to 145months for a third liver biopsy. Serum HBV DNA, hepatitis B surface antigen (HBsAg) levels, total intrahepatic HBV DNA (ihHBV DNA), cccDNA, HBV pregenomic RNA (pgRNA) as well as histologic changes were examined. RESULTS: At the time of the third biopsy, serum HBV DNA levels were undetectable in all but one patient. The median levels of HBsAg, ihHBV DNA, and cccDNA were 2.88logIU/ml, 0.03copies/cell, and 0.01copies/cell, respectively. Compared to baseline levels, there was reduction of HBsAg levels by 0.54log (71.46%), ihHBV DNA levels by 2.81log (99.84%), and cccDNA levels by 2.94log (99.89%), with 49% having cccDNA levels below the detection limit. One patient had undetectable HBsAg. The median pgRNA level, measured only in the third biopsy, was 0.021copies/cell, with 40% of patients having undetectable pgRNA. CONCLUSIONS: Long-term nucleos(t)ide analogue treatment induced marked depletion of cccDNA in the majority of patients while serum HBsAg levels, though reduced, were detectable in all but one patient. Whether cccDNA depletion is sustained and associated with better patient outcome requires further study. LAY SUMMARY: It is generally presumed that a form of hepatitis B virus DNA, called covalently closed circular DNA (cccDNA), which hides inside the nuclei of liver cells of patients with chronic hepatitis B, cannot be reduced by antiviral treatment. The present study showed that with prolonged treatment (median period 126months), cccDNA can be markedly reduced, with 49% of liver biopsies having undetectable cccDNA. This suggests that viral replication capacity would be very low after prolonged antiviral treatment.

Hepatic flare after telbivudine withdrawal and efficacy of postpartum antiviral therapy for pregnancies with chronic hepatitis B virus.

BACKGROUND AND AIM: The efficacy of telbivudine for breaking vertical transmission of hepatitis B virus has been well established. Data on the risk of postpartum flare after telbivudine withdrawal and efficacy of extended antiviral therapy after delivery are limited. METHODS: Chronic hepatitis B virus-infected women who received telbivudine beginning at week 24 or 28 of gestation were enrolled and then followed up to 52 weeks postpartum. Virological and biochemical parameters were assessed. RESULTS: Of the 241 women who finished 52 weeks of follow-up, 33.6% had elevated serum alanine aminotransferase (ALT) during pregnancy. Telbivudine administration resulted in ALT normalization in 85.2% before delivery. Compared with women having a normal ALT level throughout pregnancy, those with elevated ALT had a significantly higher rate of ALT flare after telbivudine withdrawal (25.0% vs 11.9%; χ2 = 4.273, P = 0.039). Multivariate analysis indicated that only ALT elevation during pregnancy correlated with postpartum flare after telbivudine withdrawal. Those women with elevated ALT during pregnancy continued antiviral treatment to 52 weeks postpartum and had a significantly higher HBeAg seroconversion rate (P = 0.001) and a notable decrease in HBsAg titers (P = 0.001). CONCLUSION: It is safe for the majority of women to withdraw telbivudine after delivery, whereas exciting serological response encourages extended antiviral therapy for mother with ALT elevation during pregnancy.

Comparison of the Efficacies and Safety of Combined Therapy between Telbivudine Plus Adefovir and Lamivudine Plus Adefovir in Patients with Hepatitis B Virus Infection in Real-World Practice.

BACKGROUND AND AIM: Chronic hepatitis B infection remains a significant health issue worldwide. This study evaluated the efficacy and safety of combined therapy using lamivudine plus adefovir (LAM+ADV) versus telbivudine plus adefovir (LdT+ADV) and the corresponding renal function change and safety. METHODS: This study enrolled a total of 171 patients (110 patients received LAM+ADV and 60 patients received LdT+ADV). We analyzed the changes in renal function using the estimated glomerular filtration rate (eGFR). The DNA undetectable rate, hepatitis B e antigen (HBeAg) seroconversion rate, and alanine aminotransferase (ALT) normalization rate were analyzed. We checked the serum uric acid, phosphate and creatine kinase, and lactic acid levels to analyze safety. We observed these patients for 48 to 240 weeks and checked their serum profile every 6 months. RESULTS: There was no statistically significant difference between the two groups in anti-hepatitis B virus (HBV) efficacy in terms of DNA undetectable rate, ALT normalization rate, and HBeAg seroconversion rate. Both the LAM+ADV and LdT+ADV groups had stable or improved renal function. However, a higher eGFR was found in the LdT+ADV group with continuous serum fluctuation during 3 years of combined therapy as well as a higher serum creatine kinase level. CONCLUSIONS: Long-term LdT+ADV combined therapy and LAM+ADV combined therapy were both associated with stable or improved renal function. The clinical efficacy was similar between the two groups, but the LdT group had a higher serum creatine kinase level. We need to monitor the data regularly in clinical practice.