Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatitis B virus (HBV) recurrence and de novo HBV infection are frequent events in liver transplantation recipients. Treatment with lamivudine is initially efficient in both infections but the incidence of lamivudine-resistant HBV emergence increases over time. Adefovir appears to be promising in post-liver transplantation patients with recurrent HBV infection and lamivudine-resistant HBV. This study analyzed adefovir treatment in 42 post-liver transplantation patients who developed recurrent HBV or de novo HBV infection with lamivudine-resistant HBV (54.8% HCV-coinfected). Patients received 10 mg of oral adefovir once daily for a mean period of time of 21.5 months (range from 12 to 31 months). In 62.9% of patients, ALT levels decreased significantly. Serum HBV-DNA was undetectable in 64% of the cases. Twenty percent of patients lost HBeAg marker and 13.3% of them developed anti-HBe. In 9.5% of recipients, HBsAg became negative. There was no significant change in serum creatinine levels. In only one patient was worsening of the renal function detected, making dose adjustment necessary. No other side effects were reported. Our results confirm the efficacy and safety of adefovir treatment in post-liver transplantation patients with lamivudine-resistant HBV, neither were adefovir-resistant mutations identified in patients after 21 months of therapy, nor were there adverse events, especially renal toxicity.
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PMID:Study on the efficacy and safety of adefovir dipivoxil treatment in post-liver transplant patients with hepatitis B virus infection and lamivudine-resistant hepatitis B virus. 1638 96

When assessing patients with chronic hepatitis B virus (HBV) infection, consider the state of viral replication, the immune response and whether viral mutations could be present, as well as evidence for liver disease or extrahepatic manifestations. In wild-type infections, loss of hepatitis B e antigen (HBeAg), gain of anti-HBe and disappearance of HBV DNA from serum indicate immunosuppression of viral replication, or 'nonreplicative chronic HBV infection'. This 'healthy carrier' state must be distinguished from HBeAg-negative chronic hepatitis B (CHB) resulting from precore and core promoter mutations. HBeAg-negative CHB is common with genotypes D (Mediterranean region, south Asia) and C (north Asia) infections. Age, disease activity (alanine aminotransferase level) and severity (fibrosis stage, cirrhosis) influence treatment decisions. Following the marginal effectiveness of interferon and often temporary effectiveness of lamivudine due to drug resistance, treatment of CHB is entering a new era. Adefovir, entecavir, tenofovir, telbivudine and clevudine have equal or superior antiviral efficacy to lamivudine, whereas several agents are effective against lamivudine-resistant HBV. Pegylated-interferon (peginterferon) is superior to conventional interferon for obtaining sustained immunosuppression of HBV without drug resistance. Antiviral suppression of HBV replication for 2-5 years reverses hepatic fibrosis, prevents cirrhosis and, when cirrhosis is established, improves liver function, prevents hepatic decompensation and lowers the risk of liver cancer. Before embarking on immunosuppressive chemotherapy or organ transplantation in patients with chronic HBV infection, it is important to start antiviral therapy to prevent hepatitis flares. Antiviral therapy can be effective against membranous glomerulonephritis and polyarteritis nodosa caused by HBV. Further improvements in treatment of CHB are needed to prevent drug resistance and permanently suppress viral replication by eradicating viral templates or stimulating host immune responsiveness to HBV.
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PMID:Management of chronic hepatitis B virus infection: a new era of disease control. 1647 64

Chronic hepatitis B is a common disease and approximately 20% of infected patients with compensated cirrhosis will decompensate over 5 years. If untreated, the survival of decompensated cirrhosis is poor (15% at 5 years). The extent of hepatitis B virus (HBV) replication, as assessed by serum HBV-DNA level, is a strong predictor of the risk of disease progression and hepatocellular carcinoma. This provides a rationale for antiviral therapy to arrest progression of liver disease. Lamivudine is a pyrimidine analogue that inhibits HBV-DNA reverse transcriptase. It decreases HBV replication, normalises alanine aminotransferase levels and reduces hepatic inflammation and fibrosis in patients with chronic hepatitis B. This article will focus on the use of lamivudine in patients with HBV-cirrhosis. In patients with compensated HBV-cirrhosis, a randomised, placebo-controlled trial has shown that lamivudine significantly reduced the rate of disease progression and hepatocellular carcinoma development over a 3-year period. In patients with decompensated cirrhosis, treatment with lamivudine can produce spectacular improvements of liver function, but the improvement is slow and a clinical benefit is usually not observed until after at least 3-6 months of treatment. A major drawback of lamivudine treatment is the development of resistance, observed in 15-20% of patients after 1 year and up to 70% after 5 years of continued treatment. Thus, patients with HBV-cirrhosis treated with lamivudine should have regular monitoring of serum HBV-DNA levels and prompt institution of additional antiviral therapy if viral breakthrough is observed. Adefovir, tenofovir and entecavir have demonstrated efficacy in patients with lamivudine resistance. In patients with decompensated cirrhosis, in whom the development of resistance can be fatal, combination therapy (such as lamivudine plus adefovir) may prove more effective than monotherapy and this issue needs further study.
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PMID:Lamivudine treatment in patients with chronic hepatitis B and cirrhosis. 1692 9

We report a patient whose cryoglobulinemic vasculitis recurred due to reactivation of lamivudine-resistant HBV. Our patient with hepatitis B-related cryoglobulinemic vasculitis was administered lamivudine. Her vasculitis regressed, ALT normalized, HBV-DNA became negative. Under lamivudine therapy, her cryoglobulinemic cutaneous vasculitis recurred. ALT increased significantly; it was found that tyrosine-methionine-aspartate-aspartate (YMDD) motif in the DNA polymerase gene had been replaced by YIDD. Adefovir was added to lamivudine. During follow-up, her purpura disappeared, ALT normalized, HBV-DNA became negative. Our patient is the first whose cryoglobulinemic vasculitis recurred under lamivudine, who had a HBV virologic breakthrough with YMDD mutation, and was successfully treated with adefovir.
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PMID:Successful treatment with adefovir of one patient whose cryoglobulinemic vasculitis relapsed under lamivudine therapy and who was diagnosed to have HBV virologic breakthrough with YMDD mutations. 1713 20

We studied clinical and laboratory effects of 3 months of lamivudine with adefovir combination and adefovir dipivoxil (AD) alone in the treatment of patients with lamivudine-resistant hepatitis B virus (HBV) infection. Eligible patients were hepatitis B surface antigen-positive men and women with compensated liver disease who were given lamivudine at least more than 6 months and had HBV polymerase gene mutation. Patients were assigned to receive adefovir 10 mg/day (Group 1) or adefovir 10 mg once daily and lamivudine 100 mg once daily combination during first 3 months, and then stopped lamivudine and continued adefovir (Group 2). Median age was 48 years (34 males and 20 females, and 35 were HBeAg-negative). Baseline median ALT, AST, and HBV DNA levels were 66 IU/l, 49 IU/l, and 6.7 log(10) copy/ml, respectively. Median adefovir therapy time and ALT normalization time were 9 and 3.5 months, respectively. There was no significant difference between groups according to the baseline HBV DNA, ALT, HBe Ag status, age, gender, and lamivudine resistance time. Virological and biochemical responses were similar in both groups during therapy. Two patients (8%) had ALT flare more than five times upper limit of normal without any clinical decompensation in Group 1. Mild ALT elevation according to baseline levels were found in 8 (27.6%) and 4 (17.4%) patients, respectively, in Group 2 and Group 1, and no statistically significance between two groups. In conclusion, this study showed that it is not necessary to continue lamivudine therapy while switching to AD therapy. Adefovir alone is effective in the treatment of patients with lamivudine resistant HBV infection and compensated liver disease, without significant clinical and laboratory flares. However, it is not easy to say that switching to AD with cessation of lamivudine is safe, because the study population is not enough for precise conclusion and resistance may be a considerable problem against AD in patients using long-term treatment.
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PMID:Adefovir dipivoxil alone or in combination with lamivudine for three months in patients with lamivudine resistant compensated chronic hepatitis B. 1743 77

Lamivudine has a high rate of antiviral resistance. Sequential treatment of anti-hepatitis B virus (HBV) is commonly used for lamivudine resistance. We report 4 cases of patients with rapid redetection of HBV mutants during the lamivudine retreatment. The four patients received lamivudine as an initial treatment of HBV and adefovir and lamivudine as a rescue therapy consecutively. HBV-DNA level, YMDD mutations and adefovir -resistant mutations (RFMP) were tested every 3 mo during the sequential treatment. All the patients showed YMDD mutations during the initial lamivudine therapy. After adefovir therapy for lamivudine resistance, they showed viral breakthrough. Adefovir was switched to lamivudine, however, it did not induce viral suppression at all, rather increased HBV-DNA with rapid reemergence of the YMDD mutations. All the patients had ALT flares, and hepatic decompensation occurred in two patients. After switching to adefovir combined with entecavir or lamivudine for a rescue therapy, the patients had reduction in HBV-DNA and ALT improvement. These cases demonstrated that lamivudine retreatment of patients with preexposed lamivudine resistance leads to rapid reemergence of YMDD mutation with significant viral rebounds and subsequent hepatic decompensation. Sequential administration of lamivudine in patients with a prior history of YMDD mutation should be abandoned.
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PMID:Rapid re-emergence of YMDD mutation of hepatitis B virus with hepatic decompensation after lamivudine retreatment. 1866 38

It is well known that different genotypes of hepatitis B virus (HBV) have a different sensitivity to interferon-alpha or lamivudine (nucleoside analogue) antiviral therapy. However, for adefovir dipivoxil (ADV, a nucleotide analogue), the antiviral response of the different genotypes remains to be clarified. In order to evaluate the response of HBV genotypes to ADV therapy and to identify factors that might affect initial virological response, we performed a retrospective analysis on patients with chronic hepatitis B (CHB) in Chinese Han population. The study included 183 patients, who had been tested positive for hepatitis B e antigen (HBeAg) and had been treated with ADV (10 mg/day) for 48 weeks. The numbers of patients infected with HBV genotype B and genotype C were 98 and 75 cases, respectively, and the remaining 10 patients were mixture infection of genotypes B plus C or genotypes B plus D. The mean HBV-DNA reduction and HBV-DNA seroclearance of genotypes B and C at 48 weeks were 3.6 log(10) and 3.1 log(10) copies/ml (p < 0.05) and 41.8% and 34.6% (p < 0.05), respectively. There were no statistically significant differences between genotypes B and C in terms of HBeAg loss, anti-HBe seroconversion and normalization of serum alanine aminotransferase (ALT). Multivariate analysis showed that young age, low pretreatment HBV-DNA and/or elevated ALT level might be independent predictive factors associated with initial virological response. Thus, in Han CHB patients who are HBeAg-positive, HBV genotype B shows a better virological response to ADV therapy than does genotype C.
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PMID:Hepatitis B virus genotype-associated variability in antiviral response to adefovir dipivoxil therapy in Chinese Han population. 1898 54

Adefovir has a potent antiviral activity as a rescue treatment against lamivudine-resistant strains. The aim of this study was to assess the patterns of lamivudine-resistant mutations and their influence on the virologic response to adefovir rescue therapy in patients with lamivudine-resistant chronic hepatitis B. Sixty-seven patients with lamivudine-resistant chronic hepatitis B were treated with adefovir monotherapy. Baseline blood samples were analyzed for lamivudine-resistant mutations via restriction fragment mass polymorphism. Virologic responses, ALT normalization and loss of HBeAg were assessed. Serum HBV DNA levels were measured using real-time PCR at baseline and 24 weeks of adefovir therapy. Of the 67 patients with chronic hepatitis B, 65 patients (97%) had lamivudine-resistant mutations in the YMDD motif [27 (41%) rtM204I, 22 (34%) rtM204V, and 16 (25%) rtM204I/V]. In addition to the YMDD mutations, the rtL180M, rtL80I, and rtV173L mutations were also present in 78%, 43%, and 11% of patients, respectively. The rtM204V mutation always accompanied rtL180M, and rtL80I was always observed in conjunction with rtM204I. Decrease in mean serum HBV did not differ between patients carrying the rtM204I versus rtM204V mutant at week 24 (-3.3 vs. -3.3 log(10) copies/ml, respectively; P = 0.303). The presence of the rtL180M, rtL80I, and rtV173L did not significantly affect viral load reduction during adefovir administration. These results demonstrate that the rtL80I mutant is co-selected with rtM204I as a compensatory mutation in the same manner as rtL180M with rtM204V, and that adefovir shows similar antiviral efficacy against all of the evaluated patterns of lamivudine-resistant HBV mutations.
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PMID:Association of lamivudine-resistant mutational patterns with the antiviral effect of adefovir in patients with chronic hepatitis B. 1915 9

Chronic hepatitis B virus (HBV) infection is a major cause of liver disease throughout the world, leading to cirrhosis and hepatocellular carcinoma in many individuals. Children are more likely to develop chronic HBV infection as they demonstrate greater immunotolerance to the virus, and response to therapy in children remains disappointing. Three therapeutic agents for chronic HBV infection in children have been approved in the USA, including standard IFN-alpha, lamivudine and adefovir. IFN-alpha has been the most effective ( approximately 30% hepatitis B e antigen [HBeAg] seroconversion; 10% hepatitis B surface antigen [HBsAg] seroconversion), although benefits are primarily observed in children with alanine aminotransferase levels over two-times the upper limit of normal and must be weighed against significant side effects. Studies comparing the long-term outcome of chronic hepatitis B in children treated with IFN-alpha and in untreated controls show that the rate of anti-HBeAb seroconversion tends to overlap in treated and untreated patients within a few years of follow-up, suggesting that IFN-alpha simply accelerates a spontaneous event. Lamivudine's virologic response rates mirror those of IFN-alpha (23-31% HBeAg seroconversion) with easier administration and a better safety profile but lower HBsAg seroconversion (2-3%) and high rates of drug resistance. Adefovir data show low rates of resistance and a good safety profile, but virologic response was limited to adolescent patients and was lower than that of lamivudine (16% HBeAg seroconversion; <1% HBsAg seroconversion). Entecavir and tenofovir, both approved therapies for adults with chronic HBV infection, are in trials for use in children. Future therapies will probably include these agents as well as combined therapies. Finally, watchful waiting of children is an option since current therapies are only 30% effective at best, although the long-term impact of therapy in childhood on rates of cirrhosis and hepatocellular carcinoma remains unknown.
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PMID:Hepatitis B therapy in children. 1921 Jan 12

To compare the efficacy of Lamivudine (LAM) monotherapy and combination therapy with Adefovir Dipivoxil (ADV) for patients with hepatitis B virus (HBV) -related decompensated cirrhosis for 2 years. A total of 115 patients with HBV-related decompensated cirrhosis were erolled in this study, among 60 patients were treated with LAM combined with ADV and 55 were treated with LAM. The liver and kidney functions, HBV DNA, HBV-M, AFP, Ultrasond or CT scan of liver were tested every 1-3months. the treatment efficacy was evaluated by month 12 and 24. By month 12, the HBV DNA negative rates of combination therapy group and LAM monotherapy group were 51.1% (45 cases) and 47.5% (40 cases) respectively, by month 24 the rates were 86.7% and 60.0% respectively. By month 24 the HBeAg negative rates of combination therapy group and LAM monotherapy group were 43.5% and 30.0% respectively, with significant difference existed between the two therapy groups (P values is less than 0.05). By month 24, the ALT normalization rates of the two groups were 88.9% and 72.5% respectively. Viral breakthrough happened in 2 cases (4.4%) by month 12 and 3 cases (6.7%) by month 24 in LAM and ADV combination group, but no viral resistance observed. Viral breakthrough happened in 9 cases (22.5%) by month 12 and 15 cases (37.5%) by month 24 in LAM monotherapy group with viral resistance observed in 7 cases (17.5%) by month 12 and 13 cases (32.5) by month 24. Significant difference existed between the two groups (P is less than 0.05). Improvement of liver function was more obviously in the combination group. The accumulative total mortality or liver transplantation rate were 16.7% and 20.0% respectively in combination therapy group and LAM monotheapy group. No renal dysfunction observed in both groups. LAM combined with ADV is better choice for patients with HBV-related decompensated cirrhosis as compared to LAM monotherapy.
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PMID:[Efficacy of lamivudine monotherapy and combination therapy with adefovir dipivoxil for patients with hepatitis B virus-related decompensated cirrhosis]. 2149 7


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