Is tenofovir disoproxil fumarate an all-powerful weapon in the treatment of chronic hepatitis B?

No abstract available.

Long-term efficacy of tenofovir disoproxil fumarate therapy after multiple nucleos(t)ide analogue failure in chronic hepatitis B patients

BACKGROUND/AIMS: The efficacy of tenofovir disoproxil fumarate (TDF) for the treatment of chronic hepatitis B (CHB) patients following prior treatment failure with multiple nucleos(t)ide analogues (NAs) is not well defined, especially in Asian populations. In this study we investigated the efficacy and safety of TDF rescue therapy in CHB patients after multiple NA treatment failure. METHODS: The study retrospectively analyzed 52 CHB patients who experienced failure with two or more NAs and who were switched to regimens containing TDF. The efficacy and safety assessments included hepatitis B virus (HBV) DNA undetectability, hepatitis B envelop antigen (HBeAg) seroclearance, alanine transaminase (ALT) normalization and changes in serum creatinine and phosphorus levels. RESULTS: The mean HBV DNA level at baseline was 5.4 +/- 1.76 log10 IU/mL. At a median duration of 34.5 months of TDF treatment, the cumulative probabilities of achieving complete virological response (CVR) were 25.0%, 51.8%, 74.2%, and 96.7% at 6, 12, 24, and 48 months, respectively. HBeAg seroclearance occurred in seven of 48 patients (14.6%). ALT levels were normalized in 27 of 31 patients (87.1%) with elevated ALT at baseline. Lower levels of HBV DNA at baseline were significantly associated with increased CVR rates (p < 0.001). However, CVR rates did not differ between TDF monotherapy or combination therapy with other NAs, and were not affected by mutations associated with resistance to NAs. No significant adverse events were observed. CONCLUSIONS: TDF is an efficient and safe rescue therapy for CHB patients after treatment failure with multiple NAs.

Pharmacokinetics of tenofovir in Beagle dogs after oral dosing of tenofovir dipivoxil fumarate using HPLC-MS/MS analysis / 药学学报

A simple, rapid and sensitive method was developed for the quantification of tenofovir in plasma of Beagle dogs using HPLC-MS/MS analysis. The analytes tenofovir and internal standard (IS) adefovir were separated on a Zorbax SB-C18 column (3.5 microm, 100 mm x 2.1 mm, Agilent, USA) with mobile phase of methanol/water containing 0.3% formic acid using a gradient elution mode at a flow rate of 0.2 mL x min(-1). The plasma sample preparation was a simple deproteinization by the addition of 20% trichloroacetic acid followed by centrifugation. The detection was performed in positive selected reaction monitoring (SRM) mode with an electrospray ionization (ESI) source. The reactions monitored were m/z 288.1-176.2 for tenofovir and m/z 274.1-162.2 for adefovir (IS). Linear detection responses were obtained for tenofovir ranging from 10 to 5 000 ng x mL(-1). The intra- and inter-day precisions (RSD%) was no more than 6.3% with high recovery and good stability for the quantification, indicating the present method was specific, fast, accurate and reliable. The method was successfully applied to the pharmacokinetic study of two tenofovir agents. Tenofovir dipivoxil fumarate (BP0018, test agent) and tenofovir disoproxil fumarate (reference agent) were orally administrated to 8 Beagle dogs according to the 2 x 2 crossover design. Comparing with the reference agent, the longer MRT and t1/2 were obtained in the group of BP0018, while no significant difference was observed in AUC(0-t), AUC(0-infinity), C(max) and t(max) between them, suggesting that tenofovir dipivoxil fumarate was bioequivalent to the tenofovir disoproxil fumarate in Beagle dogs.

High efficacy of adefovir and entecavir combination therapy in patients with nucleoside-refractory hepatitis B / 대한간학회지

BACKGROUND/AIMS: Newly developed and potent antiviral agents suffer from the problem of drug resistance. Multidrug resistance is a major impediment in the treatment of patients with chronic hepatitis B (CHB). In line with American Association for the Study of Liver Diseases guidelines, adefovir dipivoxil (ADV) add-on therapy is recommended in the case of lamivudine resistance, while tenofovir disoproxil fumarate (TDF) is recommended for ADV or entecavir (ETV) resistance. TDF is currently not available in Korea. ADV+ETV combination therapy may be a viable alternative to TDF in patients with either ADV or ETV resistance. However, the efficacy of ADV+ETV combination therapy in patients with CHB and multidrug resistance is unclear. This study investigated the efficacy of ADV+ETV combination therapy in patients with multidrug resistance. METHODS: Twenty-five patients were enrolled and were administered ADV+ETV combination therapy for at least 6 months. Blood was drawn at baseline and at 3, 6, 9, and 12 months after commencing treatment, and the following blood parameters were analyzed: alanine transaminase, hepatitis B e-antigen (HBeAg), anti-hepatitis B e-antigen, and hepatitis B virus (HBV) DNA levels. The initial virological response (IVR) was defined as an HBV DNA level of or =5.0 log) dropped from 76% at baseline to only 5% after 6 months of treatment. The biochemical response rate during the first 6 months was 71%. HBeAg was lost in 2 patients (10%). CONCLUSIONS: ADV+ETV combination therapy induced a good IVR in CHB patients who were refractory to more than 2 antiviral agents. This regimen may be a good alternative to TDF in Korea, where that drug is not available.

Simultaneous detection of hepatitis B virus genotypes and mutations associated with resistance to lamivudine, adefovir, and telbivudine by the polymerase chain reaction-ligase detection reaction

OBJECTIVES: Detection of mutations associated to nucleos(t)ide analogs and hepatitis B virus (HBV) genotyping are essential for monitoring treatment of HBV infection. We developed a multiplex polymerase chain reaction-ligase detection reaction (PCR-LDR) assay for the rapid detection of HBV genotypes and mutations associated with lamivudine, adefovir, and telbivudine resistance in HBV-infected patients. METHODS: HBV templates were amplified by PCR, followed by LDR and electrophoresis on a sequencer. The assay was evaluated using plasmids that contained wild-type or mutant HBV sequences and 216 clinical samples. RESULTS: The PCR-LDR assay and sequencing gave comparable results for 158 of the 216 samples (73.1 percent) with respect to mutation detection and genotyping. Complete agreement between the two methods was observed for all the samples (100 percent) at codon 180 and codon 204. Concordant results were observed for 99.4 percent of the 158 samples at codon 181 and 98.7 percent at codon 236. The genotyping results were completely concordant between the PCR-LDR assay and sequencing. The PCR-LDR assay could detect a proportion of 1 percent mutant plasmid in a background of wild-type plasmid. CONCLUSION: The PCR-LDR assay is sensitive and specific for detection of HBV genotypes and drug resistance mutations, and could be helpful for decision making in the treatment of HBV infection.

Virologic response is not durable after adefovir discontinuation in lamivudine-resistant chronic hepatitis B patients / 대한간학회지

BACKGROUND/AIMS: We investigated the durability of the biochemical and virologic responses after adefovir (ADV) discontinuation in lamivudine-resistant (LMV-R) chronic hepatitis B (CHB) patients, and the outcomes of ADV discontinuation compared to that of ADV maintenance. METHODS: The indication for ADV treatment cessation was an undetectable level of hepatitis B virus (HBV) DNA documented on two occasions at least 6 months apart. All patients received additional ADV for at least 12 months after the confirmation of undetectable HBV DNA (Cobas TaqMan PCR assay, <70 copies/mL). Of 36 patients who had a sufficient ADV therapeutic effect, 19 discontinued ADV treatment, while the others maintained it. A virologic rebound was arbitrarily defined as the redetection of HBV DNA at a level higher than 105 copies/mL. RESULTS: In the ADV discontinuation group, ADV treatment and additional therapy were administered for medians of 33 months (range, 12-47 months) and 18 months, respectively. The patients were followed for a median of 12 months (range, 3-30 months) after ADV cessation. During that period, 18 of 19 patients (95%) experienced viral relapse. Viral rebound was observed in six patients (32%). However, 12 of 18 patients (67%) exhibited serum HBV DNA levels of less than 105 copies/mL. Biochemical relapses were observed in four of the six patients with viral rebound. In the ADV maintenance group, patients were treated for a median of 53 months (range, 31-85 months), and 9 patients (53%) experienced viral breakthrough. CONCLUSIONS: During short-term follow-up after ADV discontinuation, most patients (95%) exhibited viral relapse, whereas and viral breakthrough occurred in about half of patients (53%) maintained on ADV therapy. Therefore, the durability of virologic response after ADV discontinuation in LMV-R patients was unsatisfactory. In addition, and viral breakthrough was not infrequent in the ADV continuation group.

Avaliação da eficácia do cidofovir na papilomatose respiratória recorrente juvenil / Efficacy of cidofovir in recurrent juvenile respiratory papillomatosis

O uso do cidofovir para papilomatose respiratória recorrente juvenil (PRRJ) ainda não tem estudos caso-controle suficientes que comprovem sua eficácia em literatura. OBJETIVO: Avaliar fatores que influenciem o prognóstico da PRRJ, e observar a atuação do cidofovir na erradicação da PRRJ. DESENHO DO ESTUDO: Retrospectivo. MATERIAIS E MÉTODOS: 22 crianças com PRRJ foram avaliadas num centro terciário. Todas as crianças foram submetidas ao tratamento cirúrgico, seguido (Grupo 2) ou não (Grupo 1) pelo uso do cidofovir. A idade ao diagnóstico foi correlacionada ao escore de Derkay e à evolução da doença. Os Grupos 1 e 2 tiveram suas evoluções comparadas entre si. RESULTADOS: Quinze crianças foram consideradas curadas, 8 no Grupo 2 e 7 no Grupo 1. Houve uma correlação negativa entre idade e Escores Total e Clínico (P<0,05). O número médio de cirurgias necessárias para controlar a doença foi semelhante entre os Grupos, mas a duração do tratamento até remissão foi significativamente maior no Grupo 1 quando comparado ao Grupo 2 (P<0,05). CONCLUSÕES: A PRRJ é mais agressiva quanto mais nova a idade do paciente ao diagnóstico. Pacientes tratados com cidofovir apresentaram duração significativamente menor de tratamento até erradicação da PRRJ do que os submetidos apenas ao tratamento cirúrgico.

The efficacy of cidofovir in juvenile recurrent respiratory papillomatosis (JRRP) remains uncertain due to the lack of published case-control studies. AIM: To establish factors affecting the progression of JRRP prognosis, and to evaluate cidofovir for eradicating JRRP. STUDY DESIGN: Retrospective. METHODS: 22 children with JRRP were evaluated at a referral center. All children underwent surgical debulking, followed by cidofovir injection (Group 2) or not (Group 1). Age at diagnosis was correlated with the Derkay score and disease outcome. Disease progression was compared between groups 1 and 2. RESULTS: fifteen children were considered disease-free; 8 were in Group 2 and 7 in Group 1. Age and total and clinical scores (P<0.05) were negatively correlated. The mean number of surgeries required to control the disease was identical in both groups; the duration of treatment until remission was significantly higher in Group 1 (P<0,05). CONCLUSION: JRRP is more aggressive in earlier onset disease. The duration of treatment was significantly lower in patients treated with cidofovir until eradication of JRRP compared to patients treated with surgery only.

Eficácia do adefovir dipivoxil, entecavir e telbivudina para o tratamento da hepatite crônica B: revisão sistemática / The efficacy of adefovir dipivoxil, entecavir and telbivudine for chronic hepatitis B treatment: a systematic review

INTRODUÇÃO: A hepatite crônica B é uma das doenças infecciosas mais frequentes no mundo e constitui um grave problema de saúde pública MÉTODOS: Para avaliar a eficácia dos análogos de núcleosídeo/nucletídeo utilizados no seu tratamento (adefovir dipivoxil, entecavir e telbivudina) foi conduzida uma revisão sistemática de ensaios clínicos randomizados. Foram consultadas, dentre outras, as bases de dados PubMed e LILACS RESULTADOS: Foram selecionados 29 artigos entre os publicados de janeiro/1970 até dezembro/2009 CONCLUSÕES: Todos os análogos de núcleosídeo/nucletídeo apresentam eficácia superior ou similar à lamivudina. O entecavir pode ser indicado para o tratamento da hepatite B crônica como alternativa à lamivudina em pacientes HBeAg positivo e negativo virgens de tratamento, considerando seu baixo potencial de resistência viral. A adição de adefovir à lamivudina apresentou bons resultados em pacientes resistentes à lamivudina. O uso de entecavir e telbivudina nesses pacientes apresenta risco de resistência cruzada. Telbivudina é um dos mais recentes antivirais disponíveis, mas resistência antiviral já documentada representa limitação ao seu uso como opção terapêutica à lamivudina. Eventos adversos aos análogos de núcleosídeo/nucletídeo foram similares em características, gravidade e incidência quando comparados à lamivudina e placebo.

INTRODUCTION: Chronic hepatitis B is one of the most frequent infectious disease in the world and represents a serious problem of public health METHODS: A systematic review of randomized clinical trials was conducted to evaluate the efficacy of the nucleoside/nucleotide analogues (adefovir, entecavir and telbivudine) used for the treatment of chronic hepatitis B. The databases PubMed and LILACS were consulted, among others RESULTS: Twenty nine articles published between January/1970 to December/2009 were selected CONCLUSIONS: All nucleoside/nucleotide analogues demonstrate upper or similar efficacy to lamivudine. The entecavir can be appropriate for patients with chronic hepatitis B, HBeAg positive and negative treatment-naive as alternative to lamivudine, considering its low potential of viral resistance. The addition of adefovir to lamivudine presented good results in lamivudine resistant patients. The use of entecavir and telbivudine in those patients presents risk of crossed resistance. TBV is one of the most recent antivirals available, but antiviral resistance already documented represents limitation to its use as therapeutic option to LAM. Adverse events of nucleoside/nucleotide analogues were similar in characteristics, gravity and incidence when compared to the lamivudina and placebo.

Bonding agent underneath sealant: shear bond strength to oil-contaminated

This study evaluated in vitro the shear bond strength of a resin-based pit-and-fissure sealant (Fluroshield - F) associated with either an ethanol-based (Adper Single Bond 2 - SB) or an acetone-based (Prime & Bond - PB) adhesive system under conditions of oil contamination. Mesial and distal enamel surfaces from 30 sound third molars were randomly assigned to 2 groups (n=30): I - no oil contamination; II - oil contamination. Contamination (0.25 mL during 10 s) was performed after 37 percent phosphoric acid etching with an air/oil spray. The specimens were randomly assigned to subgroups, according to the bonding protocol adopted: subgroup A - F was applied to enamel without an intermediate bonding agent layer; In subgroups B and C, SB and PB, respectively, were applied, light-cured, and then F was applied and light-cured. Shear bond strength was tested at a crosshead speed of 0.5 mm/min in a universal testing machine. Means (± SD) in MPa were: IA-11.28 (±1.84); IIA-12.02 (±1.15); IB-9.73 (±2.38); IIB-9.62 (±2.29); IC-28.30 (±1.63); and IIC-25.50 (±1.91). It may be concluded that the oil contamination affected negatively the sealant bonding to enamel and the acetone-based adhesive system (PB) layer applied underneath the sealant was able to prevent its deleterious effects to adhesion.

Este estudo avaliou in vitro a resistência ao cisalhamento (RC) de um selante resinoso [Fluroshield (F); Dentsply/Caulk] em associação com um sistema adesivo com solvente a base de etanol [Adper Single Bond 2 (SB); 3M/ESPE] ou a base de acetona [Prime & Bond (PB); 3M/ESPE] após contaminação com óleo do esmalte. Superfícies mesiais e distais de esmalte de 30 terceiros molares hígidos foram aleatoriamente alocadas em 2 grupos (n=30): I - contaminação com óleo; II - sem contaminação. A contaminação foi realizada (0,25 mL;10 s) com um jato de ar/óleo após o condicionamento do esmalte com ácido fosfórico a 37 por cento. Os espécimes foram aleatoriamente alocados em subgrupos, de acordo com a técnica adesiva empregada: A - F foi aplicado sobre o esmalte condicionado sem sistema adesivo; B - SB + F; C - PB + F. RC foi testada em uma máquina universal de ensaios (0,5 mm/min; 50 kgf) e os dados analisados por ANOVA e t-teste (α=0,01). As médias de RC em MPa foram: IA-11,28 (±1,84); IIA-12,02(±1,15); IB-9,73 (±2,38); IIB-9,62 (±2,29); IC-28,30 (±1.63); e IIC-25,50 (±1,91). Conclui-se que a contaminação com o óleo afetou a adesão do selante resinoso ao esmalte e o sistema adesivo com solvente a base de acetona (Prime & Bond) aplicado sob o selante foi capaz de impedir os efeitos deletérios da contaminação com óleo.

Add on Lamivudine to Adefovir Monotherapy for the Treatment of Lamivudine-resistant Chronic Hepatitis B Patients / 대한소화기학회지

BACKGROUND/AIMS: Add on adefovir (ADV) to ongoing lamivudine (LAM) has been recommended as a standard therapy for the treatment of LAM resistance. In the past, switch to ADV monotherapy was suggested as an option for the treatment of LAM resistance, leading to frequent development of ADV resistance. However, ADV monotherapy has been still used in LAM-resistant patients because of low cost in Korea. The aims of this study were to evaluate the virologic response and virologic breakthrough during adding on LAM in LAM-resistant patients receiving ADV monotherapy. METHODS: The study population comprised 99 patients with LAM-resistance. We divided them into 3 groups (Group 1: switch to ADV monotherapy, N=58, Group 2: add on ADV to ongoing LAM, N=25, Group 3: add on LAM to ADV monotherapy, N=16). HBV DNA levels were assessed at baseline and every 3 months during therapy. Serum HBV DNA levels were measured by bDNA assay or the COBAS TaqMantrade mark HBV test. RESULTS: The median treatment duration for group 1, group 2, and group 3 was 42.0, 20.6, and 31.8 (18.7 mon. of ADV+13.1 mon. of LAM) months, respectively. Cumulative rate of virologic breakthrough in group 1 was 5.2%, 19.0%, and 25.9% at 12, 24, and 36 months of treatment, respectively. Virologic breakthrough was not detected in group 2 and group 3 (p=0.016, group 1 vs. group 2 or 3). In group 3, median serum HBV DNA levels were 4.22 log10 copies/mL prior to LAM administration. Median serum HBV DNA changes from baseline (log10 copies/mL) were -0.91, -1.93, -1.87 and -1.74 at week 12, 24, 36 and 48, respectively. CONCLUSIONS: Later add on LAM to ADV monotherapy prevented the development of ADV resistance in patients with LAM resistance effectively, comparable to ADV add on to continuing LAM therapy.

A Case of Osteomalacia Related to Adefovir in a Patient with Chronic Hepatitis B / 대한소화기학회지

Adefovir dipivoxil, an acyclic nucleoside analogue, has been approved for the treatment of patients with chronic hepatitis B. This agent is efficacious particularly in those who have developed lamivudine resistance. The report according to hypophosphatemia induced by low dose adefovir therapy is very rare. We report one case in which osteomalacia with hypophosphatemia developed in a patient with chronic hepatitis B on adefovir dipivoxil at a low dose, 10 mg daily. A 66-year-old man, who had been taking adefovir for more than 4 years due to lamivudine resistance, presented with muscle weakness and bone pain in both thighs. After 3 years of adefovir therapy, hypophosphatemia and elevated serum alkaline phosphatase levels had been noted. A bone scan showed multiple hot uptakes. All the image findings and clinical symptoms, such as bone pain and muscle weakness were improved after correcting the hypophosphatemia with oral phosphorous supplementation.

Antiviral Efficacy of Lamivudine/Adefovir Combination Therapy in Chronic Hepatitis B Patients with Resistance to Lamivudine and Adefovir Consecutively / 대한소화기학회지

BACKGROUND/AIMS: The aim of this study was to elucidate the antiviral efficacy of lamivudine (LMV)-adefovir (ADV) combination therapy in chronic hepatitis B patients who showed resistance to LMV and ADV consecutively. METHODS: A retrospective review was performed in eighteen patients with chronic hepatitis B who developed virologic breakthroughs during LMV-ADV sequential mono-therapy and treated with LMV-ADV combination therapy. RESULTS: The median duration of follow up was 17 months (range, 6-27) after the start of LMV-ADV combination therapy. Mean HBV DNA level in log10 IU/mL was 6.08+/-0.95, 4.05+/-1.66, 3.17+/-1.58, 3.18+/-2.16, and 2.35+/-1.52 at 0, 3, 6, 12, and 24 months, respectively. Sixteen patients (88.9%) showed HBV DNA reduction below detection limit (<20,000 IU/mL). HBeAg seroconversion was observed in one patient (7.1%) after 8 months of combination therapy. Virologic breakthrough occurred in only one patient after 21 months of combination therapy. Viral rebound occurred in two patients at 12 months and 14 months of combination therapy. Normalization of serum ALT was achieved in twelve patients (66.7%). Primary non-response was observed in two cases (11.1%). CONCLUSIONS: LMV-ADV combination treatment was effective in 88.9% of patients with resistance to LMV and ADV in a short-term follow up. It may be applied as a bridge therapy until another effective antiviral regimen becomes available.

Treatment of Hepatitis B Virus Resistant to Lamivudine and Adefovir / 대한소화기학회지

No abstract available.

Aplicação local de cidofovir como tratamento adjuvante na papilomatose laríngea recorrente em crianças / Local application of cidofovir as adjuvant therapy in recurrent laryngeal papillomatosis in children

OBJETIVO: Avaliar a eficácia da aplicação local de cidofovir em associação com o tratamento cirúrgico na papilomatose laríngea recorrente (PLR) em crianças. Desenho do estudo: Prospectivo. MÉTODOS: Quatorze pacientes, com idade média de 4.7 anos e com duas ou mais recidivas após tratamento cirúrgico, foram submetidos à ressecção dos papilomas e injeção de 22.5 mg de cidofovir (7,5 mg/ml) no tecido de onde as lesões foram removidas. Após intervalos de 2-3 semanas, a mesma dose de cidofovir foi repetida duas ou três vezes. Em caso de recidiva, um novo ciclo de cirurgia seguido de aplicações locais de cidofovir era reiniciado. Cinco crianças apresentavam HPV-6 e cinco HPV-11; em quatro casos a tipagem não foi realizada. RESULTADOS: Antes do início do estudo, os pacientes eram submetidos, em média, a duas cirurgias por ano para o controle das recidivas; após o tratamento com cidofovir, a taxa anual de cirurgia diminuiu para 1,1 (p = 0,013). O intervalo médio entre as recidivas antes do início do estudo era de 1.6 meses; ao final do estudo, o intervalo aumentou para 4,4 meses (p = 0,014). Os pacientes com HPV-6 não apresentaram alteração significante nos intervalos entre as recidivas após o tratamento com cidofovir, enquanto 60 por cento das crianças com HPV-11 encontravam-se livres de doença ao final do estudo. CONCLUSÃO: O cidofovir é um adjuvante eficaz no tratamento da PLR em crianças, quando utilizado sob a forma de aplicações locais em associação com a ressecção cirúrgica das lesões. O HPV-11 pode ser mais susceptível aos efeitos benéficos do cidofovir.

OBJECTIVE: Evaluate the efficacy of local application of cidofovir in association with surgical treatment of recurrent laryngeal papillomatosis in children. Study design: Prospective. METHODS: Fourteen patients, with an average age of 4.7 years and with two or more relapses after surgical treatment, were submitted to resection of the papillomas and injection of 22.5 mg of cidofovir (7.5 mg/ml) in the tissue where the lesions had been removed. After 2 to 3 week intervals, the same dose of cidofovir was repeated two or three times. In the case of relapse, a new cycle of surgery followed by local applications of cidofovir was repeated. Five children presented HPV-6 and five HPV-11, while in four, the type was not determined. RESULTS: Before beginning of the study, patients were submitted, on the average, to 2 operations a year for control of relapses. After treatment with cidofovir, the annual rate for surgery dropped to 1.1 (p = 0.013). The average interval between relapses before beginning of the study was 1.4 months; at the end of the study, the interval reached 4.4 months (p = 0.014). Patients with HPV-6 did not show a significant change in the intervals between relapses after treatment with cidofovir, while 60 percent of the children with HPV-11 were disease free at the study end. CONCLUSION: Cidofovir was found to be an effective adjuvant in the treatment of recurrent laryngeal papillomatosis in children, when used in the form of local applications in association with surgical resection of the lesions. HPV-11 may be more susceptible to the beneficial effects of cidofovir.

Analysis of the cost-effectiveness of antiviral therapies in chronic hepatitis B patients in Korea / 대한간학회지

BACKGROUND/AIMS: The purpose of this study was to evaluate the cost-effectiveness of 1 year and up to 5 years of antiviral treatment for chronic hepatitis B (CHB). METHODS: Two ten-health-state Markov models were developed for CHB patients. The proportion of patients remaining alive in each health state, and healthcare costs and quality-adjusted life years (QALYs) were determined during annual cycles of these Markov models. The total healthcare costs, life years, and QALYs over the 40-year time horizon of the model were calculated. The perspectives of the cost-effectiveness analysis were the Korean healthcare system and the healthcare needs of the CHB patient. RESULTS: Short-course therapy with alpha-interferon or 1-year treatment with pegylated interferon alpha-2a, lamivudine (LMV), or adefovir (ADV) had limited impact on disease progression. In contrast, either LMV-ADV or ADV-LMV as rescue medication administered for 5 years resulted in a more sustained decrease in the rate of disease progression. The cost-effectiveness threshold in Korea was estimated to be approximately 25,000,000 South Korean won. LMV administered for 1 year is cost-effective in comparison with no treatment for both HBeAg-positive and HBeAg-negative CHB patients, but longer duration antiviral therapies administered for up to 5 years in CHB patients were found to be highly cost-effective by international standards. CONCLUSIONS: Antiviral treatment of CHB with LMV or ADV for up to 5 years using the alternative antiviral agent as rescue medication appears to be a cost-effective strategy for both HBeAg-positive and HBeAg-negative CHB patients in Korea. Economic evaluation of antiviral therapies should be studied further and updated, particularly for newer agents.

Virologic response to adefovir dipivoxil monotherapy is not durable in HBeAg-positive, lamivudine-resistant chronic hepatitis B patients / 대한간학회지

BACKGROUNDS/AIMS: It has been shown that adefovir dipivoxil is an effective antiviral agent in the treatment of chronic hepatitis B (CHB), not only in wild-type hepatitis B virus (HBV) infection, but also in lamivudine-resistant (LAMV-R) cases. However, little is known about the durability of the virologic response to adefovir in LAMV-R CHB patients. METHODS: Fifteen HBV e-antigen (HBeAg)-positive, LAMV-R CHB patients showed a virologic response to adefovir monotherapy. These patients received additional adefovir for at least a further 12 months. The virologic relapse rate after discontinuation of adefovir was evaluated. In addition, predictive factors associated with virologic relapse were investigated. RESULTS: The median level of serum HBV DNA before adefovir administration was 7,457,840 IU/mL (range 107,920-99,524,960 IU/mL). The median duration of adefovir treatment was 30 months (range 14-46 months). During a median follow-up period of 14 months after discontinuation of adefovir, the 1-, 2-, 3-, 6-, and 12-month cumulative relapse rates were 26.7%, 53.3%, 73.3%, 80%, and 80%, respectively. High pretreatment HBV DNA levels were found to be the only factor that was predictive of off-therapy relapse. CONCLUSIONS: Our data suggest that the adefovir-monotherapy-induced virologic response is not durable in most patients with LAMV-R HBeAg-positive CHB, especially in those with a high pretreatment HBV DNA level.

Management of Chronic Hepatitis B in Treatment-Naive Patients / 대한소화기학회지

Chronic hepatitis B (CHB) is a serious health problem in Korea. The natural history of chronic HBV infection has been divided into 4 phases: immune tolerance, immune clearance, inactive HBsAg carrier state and reactivation. During the phases of immune tolerance and inactive HBsAg carrier state, no treatment is required. Patients in the immune clearance or reactivation phases are candidates for therapy. In the last years, treatment effects of CHB have considerably improved. Several agents are currently approved for the treatment of CHB: interferon alpha, pegylated interferon alpha, lamivudine, adefovir, entecavir, telbivudine and clevudine in Korea. The treatment recommendations from the 2004 Korean Association for the Study of the Liver guideline on the management of CHB have been updated to incorporate new therapeutic options. What is uncertain is which agent or combination of agents is most effective, how long therapy should last, and which criteria should be used to start, continue, switch or stop therapy. Issues for consideration include efficacy, safety and incidences of resistance, and method of administration of antiviral therapy in treatment-naive patients.

Management of Antiviral-Resistant Chronic Hepatitis B Virus Infection / 대한소화기학회지

Substantial progress has been made in the treatment of chronic hepatitis B during the past decade. Nucleos(t)ide analogues are now widely used due to their convenience, less side effects, and considerable response rates. However, development of antiviral resistance is a major problem being considered as the most important factor for the treatment failure. Viral breakthrough associated with selection of antiviral-resistant hepatitis B virus (HBV) is usually followed by biochemical breakthrough, clinical deterioration, and even progressive liver failure. Therefore, appropriate management of antiviral resistance is critical for improving treatment outcomes. Strategies for the management of antiviral-resistant chronic HBV infection are described herein considering recently published guidelines. Lamivudine/telbivudine resistance can be managed by adding adefovir. Switching to adefovir or entecavir is also a viable option. However, careful follow-up of viral load is mandatory to detect any primary or secondary treatment failure in case of sequential monotherapy. Interferon or peg-interferon therapy can also be considered in case of young patients with compensated liver disease. For adefovir resistance, lamivudine can be added, but adding or switching to entecavir is a more reasonable option. Likewise, adding or switching to adefovir can be considered for entecavir resistance. Adding or switching to tenofovir needs to be considered upon availability. Experiences for clevudine resistance are still lacking, and need to be studied further upon the isolation of clinically resistant strains. To avoid emergence of resistant mutations, antiviral therapy should be initiated after careful balance of risk and benefit, and the most potent antiviral agent with the lowest resistance rate should be selected.

Development of Clevudine Resistance after Switching from Lamivudine in a Patient with Chronic Hepatitis B / 대한소화기학회지

Clevudine is a nucleoside analog of the unnatural beta-L configuration which has potent antiviral activity against hepatitis B virus (HBV). Clevudine is expected to have similar pattern of resistance profile as lamivudine. However, there was no report on the mutation associated with clevudine resistance in patients with chronic hepatitis B. We report a case of young male patient with chronic hepatitis B who presented with clevudine resistance. The patient had received lamivudine therapy for 5 months with reduced serum HBV DNA levels. Then, lamivudine was switched to clevudine monotherapy. After the 6 months of clevudine therapy, the patient developed virologic breakthrough (>1.0x10(8) copies/mL) as well as biochemical breakthrough, which was associated with the presence of rtM204I plus rtL80I mutant. After switching from clevudine to adefovir, the viral load decreased with biochemical improvement.

Factors affecting initial virologic response and emergence of resistant mutants after adefovir treatment in lamivudine-resistant chronic hepatitis B patients / 대한간학회지

BACKGROUND/AIMS: Adefovir dipivoxil (adefovir) effectively inhibits both wild-type and lamivudine-resistant hepatitis B virus (HBV) replication. The development of adefovir resistance is both delayed and infrequent compared with lamivudine resistance. The aim of this study was to characterize the serologic, biochemical, and virologic response to adefovir, and to explore the factors affecting initial virologic response (IVR, defined as a decrease in serum HBV below 4 log10copies/mL after 6 month of treatment) and adefovir resistance in lamivudine resistant HBV-infected patients. METHODS: This study population comprised 76 patients with lamivudine-resistance who had received adefovir for more than 12 months between March 2004 and December 2006. The adefovir-resistant mutant was assayed at 6 months and 12 months during adefovir administration. Restriction-fragment mass polymorphism analysis was used for detecting YMDD and adefovir mutants. RESULTS: After adefovir administration, an IVR was observed in 31% of the patients with lamivudine resistance. Factors associated with an IVR were HBeAg negativity (P=0.04) and the presence of liver cirrhosis (P=0.04). Age, sex, pretreatment levels of alanine aminotransferase and aspartate aminotransferase, pretreatment HBV DNA levels, presence of precore mutation, and type of YMDD mutants were not related to an IVR during adefovir treatment. The prevalence of adefovir resistance was 5% and 13% at 6 months and 12 months after therapy, respectively. Mixed infection of the precore mutant was a risk factors for the emergence of adefovir resistance (P=0.01). CONCLUSIONS: Lamivudine-resistant HBV patients exhibiting HBeAg negativity and liver cirrhosis were more likely to achieve an IVR after adefovir therapy. Adefovir resistance was associated with mixed infection of the precore mutant.