In vitro susceptibility of lamivudine-resistant hepatitis B virus to adefovir and tenofovir

Emergence of lamivudine-resistant hepatitis B virus (HBV) is a major concern in human immunodeficiency virus (HIV) and HBV coinfected patients. Following selection of resistant mutants, hepatitis flare or rapid progression to cirrhosis may occur. Treatment of patients with new nucleotide analogues such as adefovir dipivoxil (ADV) or tenofovir disoproxil fumarate (TDF) has shown good efficacy in controlling wild-type or lamivudine-resistant HBV replication. The purpose of this study was to assess the in vitro efficacy of new nucleotide analogues on HBV strains isolated from lamivudine-treated patients. After purification of HBV DNA from patient sera, the whole HBV genome was PCR-amplified and cloned. Drug sensitivity was measured after transfection of the isolated full genomes into HepG2 cells and measurement of HBeAg, HBsAg and viral replication in the culture media under increasing drug concentrations. A wild-type strain isolated from an untreated patient served as control. In a clinical study of ADV (Gilead 460i study), seven of the 35 patients carried HBV strains with the triple lamivudine resistance-associated amino-acid changes rtV173L/L180M/M204V at baseline. Although all patients responded to ADV in this clinical study, the serum HBV reduction was lower in the seven patients with the triple mutation (median -3.3 log copies/ml) compared to the patients who had only the rtL180M/M204V mutations (median -4.1 log copies/ml) at week 48 (P=0.04, Mann-Whitney test). In our in vitro system, lamivudine IC50 on lamivudine-resistant HBV carrying amino-acid substitutions rtL180M and rtM204V within the polymerase encoding region increased by more than 16,000-fold (from 6 nM to over 100 microM) when compared to wild-type HBV. For ADV and TDF, comparison of wild-type and lamivudine-resistant HBV IC50 (rtL180M-M204V) showed, respectively, 2.85-fold (from 0.07 to 0.2 microM) and 3.3-fold (from 0.06 to 0.2 microM) increases, indicating a mild decrease of both drug activities, in vitro. At the ADV concentration of 0.1 microM, presence of the V173L mutation reduced the inhibition of HBsAg production from 50 to 30% (P<0.01) and the viral replication from 45 to 32% (P<0.01, Mann-Whitney). Conversely, tenofovir had similar potency on both HBV mutation profiles with 60% inhibition of HBsAg production and 45% inhibition of viral replication at 0.1 microM. Our study supports the high efficacy of ADV and TDF seen in patients after lamivudine breakthrough. The excellent activity of TDF on lamivudine-resistant virus independently of the resistance mutation profile offers an interesting treatment alternative to HIV-HBV coinfected patients.

Treatment of hepatitis C virus: the first decade

Interferon alfa therapy emerged as an early treatment option for patients with chronic hepatitis C. This therapy, however, fails to produce a sustained virological response in most patients. Various host and viral baseline characteristics, some of which include hepatitis C virus genotype, viral load, presence of cirrhosis, and patient age, affect the response to interferon therapy. The addition of ribavirin to interferon therapy significantly improves long-term virological response in treatment-naive patients and is also more effective than repeat interferon therapy is in patients who fail to initially achieve sustained virological or biochemical responses. However, ribavirin can induce reversible hemolytic anemia, and combination therapy with a ribavirin/interferon regimen is not tolerated as well as interferon is alone. Pegylated interferons used alone or in combination with ribavirin provide improved treatment options for different patient groups with chronic hepatitis C.

The burden cost of French patients suffering from irritable bowel syndrome

BACKGROUND

The impact of irritable bowel syndrome (IBS) on health-care resource use in France is evaluated, and explanatory variables determined.

METHODS

A questionnaire comprising socio-demographic characteristics, symptoms, consumption of resources, quality of life and impact of IBS on productivity was administered by telephone to a sample of 253 French adults with IBS recruited from the general population, and diagnosed with IBS using several well-known diagnostic criteria. The medical costs were estimated on a monthly basis and included medication(s), physicians' consultations, investigations and hospitalizations.

RESULTS

Mean age was 48.3 years and 75% of subjects were women (192). Thirty-six percent of subjects had suffered from IBS for more than 10 years; 77% had consulted a general practitioner and 43% a gastroenterologist. Twenty-nine percent of subjects had undergone an investigation and 25% reported hospitalization; 61% of patients reported that they were taking medication. The average monthly medical costs was 71.8 euros (95% CI = [57.6-86.0]) with an asymmetric distribution (median = 28.1 euros) because of a high proportion of subjects (27%) who reported receiving no care at all. The two principal cost components were investigations (39%), and hospitalizations (22%). The highest medical costs were associated with subjects who were very elderly or suffered from severe symptoms (very severe pain), and were correlated with the lowest quality of life scores.

CONCLUSION

IBS has a major impact on resource consumption and the productivity of patients. Determination of the variables to explain medical costs showed that advanced age, severe pain and deterioration in quality of life could be predictive of high medical costs.

In Vitro Susceptibility of Lamivudine-Resistant Hepatitis B Virus to Adefovir and Tenofovir

Emergence of lamivudine-resistant hepatitis B virus (HBV) is a major concern in human immunodeficiency virus (HIV) and HBV coinfected patients. Following selection of resistant mutants, hepatitis flare or rapid progression to cirrhosis may occur. Treatment of patients with new nucleotide analogues such as adefovir dipivoxil (ADV) or tenofovir disoproxil fumarate (TDF) has shown good efficacy in controlling wild-type or lamivudine-resistant HBV replication. The purpose of this study was to assess the in vitro efficacy of new nucleotide analogues on HBV strains isolated from lamivudine-treated patients.

After purification of HBV DNA from patient sera, the whole HBV genome was PCR-amplified and cloned. Drug sensitivity was measured after transfection of the isolated full genomes into HepG2 cells and measurement of HBeAg, HBsAg and viral replication in the culture media under increasing drug concentrations. A wild-type strain isolated from an untreated patient served as control. In a clinical study of ADV (Gilead 460i study), seven of the 35 patients carried HBV strains with the triple lamivudine resistance-associated amino-acid changes rtV173L/L180M/M204V at baseline. Although all patients responded to ADV in this clinical study, the serum HBV reduction was lower in the seven patients with the triple mutation (median –3.3 log copies/ml) compared to the patients who had only the rtL180M/M204V mutations (median –4.1 log copies/ml) at week 48 ( P=0.04, Mann-Whitney test).

In our in vitro system, lamivudine IC50 on lamivudine-resistant HBV carrying amino-acid substitutions rtL180M and rtM204V within the polymerase encoding region increased by more than 16000-fold (from 6 nM to over 100 μM) when compared to wild-type HBV. For ADV and TDF, comparison of wild-type and lamivudine-resistant HBV IC50 (rtL180M-M204V) showed, respectively, 2.85fold (from 0.07 to 0.2 μM) and 3.3-fold (from 0.06 to 0.2 μM) increases, indicating a mild decrease of both drug activities, in vitro. At the ADV concentration of 0.1 μM, presence of the V173L mutation reduced the inhibition of HBsAg production from 50 to 30% ( P<0.01) and the viral replication from 45 to 32% ( P<0.01, Mann-Whitney). Conversely, tenofovir had similar potency on both HBV mutation profiles with 60% inhibition of HBsAg production and 45% inhibition of viral replication at 0.1 μM.

Our study supports the high efficacy of ADV and TDF seen in patients after lamivudine breakthrough. The excellent activity of TDF on lamivudine-resistant virus independently of the resistance mutation profile offers an interesting treatment alternative to HIV–HBV coinfected patients.

Fat, diabetes, and liver injury in chronic hepatitis C

It is increasingly recognized that host factors can modulate the fibrogenic response in patients with chronic hepatitis C. Obesity, because of its prevalence, and diabetes, which seems to occur more frequently in patients infected by the hepatitis C virus (HCV), are often present in patients with chronic hepatitis C. Both conditions result in fatty liver, which in turn is associated with more severe liver damage, especially fibrosis or inflammation. Steatosis can either originate from associated metabolic alterations (insulin resistance resulting in metabolic steatosis) or from a direct cytopathic effect of the virus (genotype 3, resulting in viral steatosis). Metabolic steatosis seems to be a factor in resistance to antiviral therapy, whereas viral steatosis is reduced in sustained responders. Whether metabolic steatosis has a direct role in liver fibrosis progression or is only a surrogate marker of an underlying defect triggering fibrogenesis, such as insulin resistance, is a subject of debate. High serum glucose levels and diabetes have a strong and independent profibrogenic impact. Exciting new data are expanding our understanding of the mechanisms of steatogenesis in HCV infection and providing potential links between insulin resistance or hyperglycemic states and liver fibrogenesis.

Comparing the public health burden of chronic hepatitis C and HIV infection in France

BACKGROUND/AIMS

In France, the prevalence of hepatitis C virus (HCV) exceeds that of HIV, but in the absence of treatment, HIV infection progresses more rapidly than HCV. More HIV-infected patients, however, have received treatment. Using reported public health data in France and natural history models, we applied the back-calculation method to project future mortality from HCV and HIV incorporating current therapies.

METHODS

The HCV model was based on literature data for the natural history of HCV and reports of hepatocellular carcinoma mortality. The HIV model used estimates from the French Hospital Database on HIV and reported AIDS cases and deaths.

RESULTS

Peak annual mortality from HIV at 5000 occurred in 1994 and was 1000 in 1998, but HCV mortality likely increased through the 1990s and reached 3000 in 1998. Considering only HCV infections occurring until 1998 and currently available therapy, our model suggested that annual HCV-related mortality would continue to rise and would reach 4500 deaths in 2022. In contrast, AIDS-related deaths began to decrease in 1997.

CONCLUSIONS

The public health burden of HCV is likely on the rise, while the burden of HIV, given the fairly widespread use of effective medications, may be on the decline. These results may help health policymakers in planning their responses to these epidemics.

The renal tolerance of low-dose adefovir dipivoxil by lamivudine-resistant individuals co-infected with hepatitis B and HIV

BACKGROUND

Adefovir (ADV), an orally administered nucleotide analogue active against hepadnaviruses, retroviruses and herpes viruses was shown to be effective in HIV-infected patients, but the prevalence of nephrotoxicity with doses of 60-120 mg/day was considered unacceptable. Recently, lower doses of ADV were shown to be effective for the treatment of HIV-1 patients with chronic lamivudine (LAM)-resistant hepatitis B.

METHODS

In a cohort of 35 patients infected with both HIV-1 and LAM-resistant hepatitis B virus, we investigated the renal tolerance of a once-daily dose of ADV 10 mg over 52 weeks. Their mean baseline creatinine clearance was within the normal range (105 +/- 3 ml/min/1.73 m(2)). No patient had significant changes in renal function or electrolyte balance secondary to ADV treatment.

RESULTS

Transient increases in serum creatinine, which resolved by the end of the study were noted in two patients and three developed proteinuria, which was felt to be unrelated to ADV treatment. The cohort's mean serum phosphate level, 2.45 +/- 0.09 mg/dl at baseline, did not change significantly under treatment (2.66 +/- 0.12 mg/dl at week 52, P = NS).

CONCLUSIONS

Our study shows that ADV dosed at 10 mg/day for the treatment of LAM-resistant chronic hepatitis B in patients co-infected with HIV is not associated with renal tubular dysfunction or a significant change in renal function.

Gemcitabine plus oxaliplatin for patients with advanced hepatocellular carcinoma using two different schedules

BACKGROUND

New therapies are needed to improve the prognosis of patients with advanced hepatocellular carcinoma (HCC). Various gemcitabine-oxaliplatin combinations have been tested recently in patients with ovarian and pancreatic carcinoma, yielding interesting results with little toxicity. Therefore, the authors evaluated the activity and toxicity of two such combinations in patients with HCC.

METHODS

Twenty-one patients were enrolled prospectively in the study. Eleven patients received gemcitabine 1000 mg/m2 on Day 1 and oxaliplatin 100 mg/m2 on Day 2 (GEMOX-1), and 10 patients received gemcitabine 1500 mg/m2 on Day 1 followed by oxaliplatin 85 mg/m2 on Day 1 (GEMOX-2). Treatment was repeated every 2 weeks until disease progression developed or until unacceptable adverse effects occurred.

RESULTS

All patients were assessable for response and toxicity. Four patients (19%) achieved objective responses (95% confidence interval, 13-26%), including 3 patients in the GEMOX-1 group and 1 patient in the GEMOX-2 group. Ten patients (48%) had stable disease, and 7 patients (33%) experienced disease progression. The median progression-free survival was 5 months, and the median overall survival was 12 months. Fifty-four percent of patients in the GEMOX-1 group and 50% of patients in the GEMOX-2 group had received previous systemic chemotherapy or cisplatin-based chemoembolization. Grade 3-4 hematologic toxicity, according to National Cancer Institute Common Toxicity Criteria, consisted of thrombocytopenia (GEMOX-1 vs. GEMOX-2, 18% vs. 40%) and neutropenia (0% vs. 30%). No Grade 3-4 nonhematologic toxicity was observed, except for 1 episode of Grade 3 diarrhea. Grade 1 neurotoxicity and Grade 2 neurotoxicity (specific scale), respectively, were observed in 4 patients and 7 patients receiving GEMOX-1 and in 7 patients and 1 patient receiving GEMOX-2.

CONCLUSIONS

Gemcitabine-oxaliplatin combination therapy is feasible in patients with advanced HCC. The GEMOX-1 regimen was tolerated better than the GEMOX-2 regimen. Currently, the GEMOX-1 regimen is being evaluated in a Phase II study in previously untreated patients with HCC.

Decreased frequencies of virus-specific T helper type 1 cells during interferon alpha plus ribavirin treatment in HIV-hepatitis C virus co-infection

Anti-hepatitis C virus (HCV) treatment combining IFN-alpha and ribavirin (IFN+R) has still poorly defined effects on immune responses. Frequencies of T helper (Th) type 1 cells specific for HCV, cytomegalovirus (CMV) and HIV were measured in chronically HCV-infected patients with or without HIV co-infection during IFN+R treatment. Although scarce, peripheral blood HCV-specific Th1 cells did not change significantly, while frequencies of HIV and CMV-specific Th1 cells decreased in co-infected patients independently of CD4 cell count changes. This suggests that IFN+R therapy might compromise virus-specific immune defenses in immunosuppressed patients.

Pegylated interferon alpha 2b and ribavirin in HIV/hepatitis C virus-co-infected non-responders and relapsers to IFN-based therapy

BACKGROUND

Pegylated interferon alpha (PEG-IFN-alpha) and ribavirin is the most effective available treatment for chronic hepatitis C virus (HCV) infection. Its role in HIV/HCV-co-infected patients who have failed IFN-based therapy is unclear.

OBJECTIVE

The aim of this study was to determine the safety and efficacy of this therapy in HIV/HCV-co-infected non-responders and relapsers.

DESIGN

An open-label cohort study of 32 non-responders and relapsers to IFN (with or without ribavirin). Patients were treated for 48 weeks with PEG-IFN-alpha 2b and ribavirin.

MAIN OUTCOME MEASURE

A sustained virological response (SVR) defined as a negative HCV-RNA level 24 weeks after the end of treatment.

RESULTS

The mean age of the patients was 40 years; 78% were men, 67% had genotype 1, and 36% had bridging fibrosis or cirrhosis. The majority had a CD4 cell count greater than 200 cells/microl (97%) and an undetectable HIV-RNA level (81%). Fifteen patients (47%) withdrew because of adverse events, predominantly neuropsychiatric. In an intention-to-treat analysis, a SVR was observed in five patients (16%); 9% with genotype 1 versus 29% with genotype 3 and 33% with genotype 4 (P = NS). Additional, but statistically non-significant, univariate predictors of response were lower serum HCV-RNA (P = 0.07) and higher alanine aminotransferase levels (P = 0.055) at baseline. No patient with bridging fibrosis or cirrhosis responded. Treatment had a minimal impact on HIV parameters.

CONCLUSION

PEG-IFN-alpha 2b and ribavirin is a potentially useful therapy in HIV/HCV-co-infected patients who have failed standard IFN-based regimens. Strategies to improve adherence are vital so as to maximize long-term response rates.

Viral hepatitis C

More than 170 million people worldwide are chronically infected with the hepatitis C virus (HCV), which is responsible for more than 100000 cases of liver cancer per year, with similar numbers of digestive haemorrhage and ascites episodes. Major breakthroughs have been made in diagnosis and treatment, and advances in molecular biology mean that the replicative state of the virus can now be assessed. Genotype and serum viral load are useful predictors of response to treatment. The combination of pegylated interferon and ribavirin can eradicate the virus in more than 50% of patients. These antiviral treatments reduce liver fibrosis progression and can reverse cirrhosis. Unfortunately, even in developed countries, death due to hepatitis C is increasing because of inadequate detection and treatment.

Viral hepatitis B

More than 400 million people worldwide are chronically infected by the hepatitis B virus. The virus is responsible for more than 300000 cases of liver cancer every year and for similar numbers of gastrointestinal haemorrhage and ascites. Major breakthroughs have been achieved in diagnosis and treatment of this virus. Hepatitis B vaccine reduces incidence of liver cancer. As with hepatitis C, advances have been made in molecular virology, especially for naturally occurring and treatment-induced mutant viruses. The clinical significance of low viral load and genotypes are also under investigation. Currently available monotherapies-interferon, lamivudine, and adefovir dipivoxil-very rarely eradicate the virus, but greatly reduce its replication, necroinflammatory histological activity, and progression of fibrosis. Lamivudine, and presumably other nucleoside analogues, can reverse cirrhosis of the liver.

Fibrogenic impact of high serum glucose in chronic hepatitis C

BACKGROUND/AIMS

There is considerable variability in the rate of fibrosis progression in patients with chronic hepatitis C, most of which is related to factors so far unknown. We tested the hypothesis that high serum glucose and overweight might contribute to this variability.

METHODS

Seven hundred and ten patients with chronic hepatitis C with a known duration of infection and no hepatitis B virus or human immunodeficiency virus coinfection were studied. Significant fibrosis was defined as bridging fibrosis including cirrhosis. Variables were tested for their association with significant fibrosis.

RESULTS

In univariate analyses both serum glucose and body mass index were associated with fibrosis. In multivariate analyses, age at infection, duration of infection, serum glucose and daily alcohol intake but not body mass index were independently associated with significant fibrosis. Patients with high serum glucose had been contaminated at an older age and had features of the metabolic syndrome, including steatosis more frequently, as well as faster fibrosis progression rates. High serum glucose was associated with intermediate and advanced, but not with early, fibrosis stages. A high serum glucose was associated with a higher relative risk for significant fibrosis than overweight.

CONCLUSIONS

High serum glucose, is an independent co-factor of fibrosis in chronic hepatitis C with a higher pro-fibrogenic impact than overweight.

Prediction of liver histological lesions with biochemical markers in patients with chronic hepatitis B

BACKGROUND AIMS

Liver biopsy is the gold standard for assessing hepatitis B virus (HBV)-related histology. The aim was to determine the diagnostic utility of noninvasive serum markers in patients with chronic hepatitis B.

METHODS

The aminotransferases and indices including alpha(2)-macroglobulin, apolipoprotein A1, haptoglobin, gamma-glutamyl-transpeptidase (GGT), and total bilirubin (Fibrotest), and ALT (Actitest) were compared with liver histology. The primary outcomes were A2-A3 activity and F2-F4 fibrosis (METAVIR).

RESULTS

Two hundred and nine patients were included. Forty-one patients (20%) had A2-A3 activity and 61 (29%) had F2-F4 fibrosis. AST and GGT (P<0.001) were independently associated with A2-A3 activity. AST, ALT, and Actitest accurately predicted activity ((areas under receiver operating characteristic (ROC) curves (AUROC), 0.81-0.82+/-0.04)); an AST or ALT< or =30IU/l excluded significant activity with 96% certainty. Fibrotest accurately predicted F2-F4 fibrosis (AUROC, 0.78+/-0.04). Fibrotest scores (range, 0-1.0) < or =0.20 and >0.80 had negative and positive predictive values of 92%, respectively. Restricting biopsy to patients with intermediate scores (>0.20 and < or =0.80) may prevent liver biopsies in 46% of patients while maintaining 92% accuracy.

CONCLUSIONS

The aminotransferases and an index including five biochemical markers are accurate noninvasive markers of HBV-related activity and fibrosis, respectively.

Biochemical surrogate markers of liver fibrosis and activity in a randomized trial of peginterferon alfa-2b and ribavirin

Liver fibrosis and activity indexes were validated in patients infected by hepatitis C virus (HCV) nontreated and treated by interferon. The aim was to validate their usefulness as surrogate markers of histologic features using the data of a randomized trial of combination peginterferon alfa-2b and ribavirin. Three hundred fifty-two patients who had had 2 interpretable liver biopsies and stored serum sample before and after treatment were selected. Two hundred eight patients received peginterferon alfa-2b 1.5 mcg per kg and ribavirin and 144 patients interferon alfa-2b 3 MU three times a week and ribavirin for 48 weeks. A fibrosis and an activity index combining 5 and 6 biochemical markers were assessed at baseline and at end of follow-up (24 weeks after treatment). The biochemical markers have significant predictive values both for the diagnosis of fibrosis and for activity. For the diagnosis of bridging fibrosis and/or moderate necroinflammatory activity, the area under the receiver operating characteristics curve of the activity index was 0.76 +/- 0.03 at baseline and 0.82 +/- 0.02 at end of follow-up. A cutoff of activity index at 0.30 (range, 0.00-1.00) had 90% sensitivity and 88% positive predictive value for the diagnosis of bridging fibrosis or moderate necroinflammatory activity. Sensitivity analyses with biopsy specimens of size greater than 15 mm suggest that a part of discordances between biochemical markers and histology were due to biopsy specimen sampling error. In conclusion, these biochemical markers of fibrosis and activity could be used as surrogate markers for liver biopsy in patients with chronic hepatitis C, both for the initial evaluation and for follow-up.