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New findings in hepatitis C virus described from Canada, Sweden and Austria

Hepatitis Weekly - Jun. 19, 2006

2006 JUN 19 - (NewsRx.com) -- Data on hepatitis C virus are outlined in reports from Canada, Sweden and Austria.

Study 1:
According to scientists from Canada, hepatitis C virus treatment efficacy can be predicted.

"In the past, antiviral therapy has been given to 15% to 30% of patients infected with hepatitis C virus (HCV). The efficacy of therapy has recently improved with the addition of ribavirin and pegylated interferon. The aim of the present study was to identify the clinical, socioeconomic and health-system predictors of antiviral treatment for HCV," wrote M. Witkos and colleagues, University of Toronto. "A retrospective analysis of compensation claims data of patients who acquired HCV through blood transfusions between 1986 and 1990 was performed. The patients consisted of 2456 Canadian HCV-positive individuals."

The researchers wrote, "The authors reviewed narrative comments from physicians, and constructed univariate and multivariate logistic regression models, using receipt of antiviral therapy with interferon or interferon/ribavirin as the primary outcome. Of the 2456 patients, approximately 30% appeared to be eligible, but only 16% received treatment.

"Univariate analyses suggested that the disease severity, age, HIV status and province of residence were associated with the likelihood of receiving treatment (p<.01). The final, multivariable model indicated that in patients with HCV. Intermediate disease severity (eg, fibrosis, p<.0001); middle age (p<.0001); HIV-negative status (p<.0001); and province of residence (Quebec, p<.0001; and Saskatchewan, p<.0001) were independent predictors of treatment."

"Narrative comments of physicians emphasized the importance of age, HIV status and patient preferences in clinical decision-making. Given the efficacy and cost-effectiveness of current antiviral therapy, treatment rates of HCV patients may be suboptimal," reported the authors.

They concluded, "Further work is required to understand barriers to treatment related to geography, organization of medical care, age, medical provider and patient preferences."

Witkos and colleagues published their study in Canadian Journal of Gastroenterology (Predictors of antiviral therapy in a post-transfusion cohort of hepatitis C patients. Can J Gastroenterol, 2006;20(2):107-111).

For additional information, contact M.D. Krahn, University of Toronto, Toronto General Hospital, Department of Health Policy Management & Evaluation, 200 Elizabeth St., EN 14-207, Toronto, ON M5G 2C4, Canada.

Study 2:
According to recent research from Sweden, translation efficiency correlates with therapy outcome in chronic hepatitis C virus (HCV) infection.

"Combination therapy with interferon-alpha (IFN-alpha) and ribavirin (RBV) in chronic hepatitis C demonstrates the best responses against HCV of genotype 3. Still, it has proven to be ineffective in 20-30% of patients infected with this genotype.

"In the present study," wrote A. Yasmeen and colleagues, Karolinska Institute, "we analyzed the translation efficiency mediated by the internal ribosome entry site (IRES) region in HCV genotype 3 genomes isolated from sustained responders (SR) and non-responders (NR), assuming that this may influence the outcome of treatment."

The authors reported, "Pretreatment isolates of genotype 3 from 22 individuals (15 SR, seven NR) were selected for such analyses. The IRES region [nucleotide (nt) 1-407] was cloned into a dual luciferase vector and IRES activity assessed following transfection into various cell lines.

"Low relative translation efficiency was observed for IRES elements derived from SR patients, whereas those of NR patients showed significantly greater translation efficiency (29.7±13 vs 69.4±22; p<.01). Subsequently, the effect of IFN-alpha plus RBV on IRES-driven translation in vitro was determined. A greater suppressive effect was observed on IRES activity isolated from seven SR patients, when compared with seven NR patients."

"IRES efficiency in vitro correlated with treatment response for HCV genotype 3. Further studies are warranted to investigate whether IRES efficiency in vitro, or sequence motifs associated with IRES efficiency, will be worthwhile to explore as prognostic tools for other HCV genotypes in the treatment of chronic HCV infection," the investigators concluded.

Yasmeen and colleagues published their study in the Journal of Viral Hepatitis (Correlation between translation efficiency and outcome of combination therapy in chronic hepatitis C genotype 3. J Viral Hepat, 2006;13(2):87-95).

For additional information, contact M.A.A. Persson, Karolinska Institute, Center of Molecular Medicine, Karolinska Hospital, Department of Medicine, S-17176 Stockholm, Sweden.

Study 3:
According to recent research from Austria, interferon therapy is promising in treatment of chronic hepatitis C.

"Combination anti-viral therapy achieves a sustained virological response (defined as HCV-RNA negativity 6 months after the end of therapy) of 56% of patients with chronic hepatitis C. Little is known about long-term durability of HCV-RNA negativity in patients treated with pegylated interferon."

E. Formann and colleagues, Medical University of Vienna, wrote that the study was done "to evaluate the durability of virologic response in patients with sustained virological response to anti-viral therapy treated at our center."

"A total of 187 sustained virological responses (50% genotype 1, 42% genotype 2 or 3 and 8% genotype 4; 20% with cirrhosis) with a follow-up of >12 months post-therapy were studied. Twelve patients received monotherapy with interferon-alpha2a or -2b. One hundred and seventy-five received combination therapy with ribavirin and standard interferon-alpha (n=73) or pegylated interferon-alpha2a or 2b (n=102)."

"Qualitative serum HCV-RNA was tested by COBAS AMPLICOR HCV test, v2.0. Median follow-up time was 29 months (range 12-172)," explained the authors.

"Recurrence of HCV infection was not observed in any of the 187 sustained virological responders. Ala aminotransferase values were normal in 90% and two patients showed minimal elevation of alpha-fetoprotein levels. No recurrence of HCV infection was seen in any patient."

"Thus," concluded the researchers, "longterm prognosis in chronic hepatitis C patients with a sustained virological response to therapy with pegylated interferon ± ribavirin is promising, but long-term studies need to continue."

Formann and colleagues published their study in Alimentary Pharmacology & Therapeutics (Long-term follow-up of chronic hepatitis C patients with sustained virological response to various forms of interferon-based anti-viral therapy. Aliment Pharmacol Ther, 2006;23(4):507-511).

For additional information, contact P. Ferenci, Department of Internal Medicine IV, Gastroenterology and Hepatology, Medical University of Vienna, Austria, Vienna, Austria.