Learning About Liver
Fibrosis (2003)
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The Role of Antiviral Therapy in the Natural
History
of Hepatitis C Fibrosis
Joanne C. Imperial, MD
Associate Professor of Medicine
Stanford University School of Medicine
The development of
liver fibrosis is a critical event in the natural history of chronic
hepatitis C virus infection. Fibrosis is the predominant cause of
morbidity and mortality from this disease and is responsible for the
development of liver decompensation, hepatocellular carcinoma and death in a
percentage of chronically-infected individuals.
Liver biopsy is
considered mandatory for accurate staging of early fibrosis. A recent
prospective study was done to assess the accuracy of a combination of serum
biochemical markers for diagnosing fibrosis, including early stages.
Eleven serum markers were assessed, as well as the METAVIR fibrosis stage.
A fibrosis score combining the most informative markers and taking into
account age and gender was constructed. High negative-predictive
values were obtained for scores ranging from 0 to .10 and high
positive-predictive values were obtained for scores ranging from .6 to 1.0.
Using a combination of simple serum markers to predict fibrosis could
potentially lead to a 50% reduction in the number of liver biopsies
performed in patients with chronic HCV. A serum hyaluronic acid level
of <110 mcg/l was associated with a 97% negative predictive value for
significant fibrosis.
The effect on hepatic
fibrosis using pegylated interferons has recently been studied by several
investigators. Heathcote randomized 271 patients with bridging
fibrosis or cirrhosis to receive either interferon alfa-2a 3MU TIW,
peginterferon alfa-2a 90 mcg QW or peginterferon alfa-2a 180 mcg QW.
SVR was reported in 8%, 15% and 30% of these treatment groups. In a subset
of patients who underwent paired liver biopsies, histologic response
(greater than a 2-point decrease in a total Histologic Activity Index score)
at week 72 was 31%, 44% and 51% respectively. Even among those
individuals that did not have a sustained response to treatment, histologic
improvement was observed in approximately 33% of patients. Poynard
pooled individual data from 3010 treatment-naïve patients with pre and post
treatment liver biopsies from four randomized treatment trials. Ten
different regimens combining standard interferon, pegylated interferon, and
ribavirin were compared. Improvement in inflammation and necrosis
varied from 39% in patients treated with standard interferon monotherapy for
24 weeks to 73% in those treated optimally with peginterferon and ribavirin.
All regimens reduced the annual rate of fibrosis progression compared with
pretreatment rates. Fibrosis stage, sustained viral response, age less than
40 years, body mass index of <27 kg/m, minimal pretreatment inflammation,
and viral load less than 3.5 million copies/mL were independent factors
associated with the absence of significant fibrosis after treatment in this
analysis.
Although the goal of
antiviral therapy is to achieve sustained viral eradication, recent studies
have suggested that secondary goals of preventing progression of fibrosis or
liver cancer can be accomplished, even in treatment nonresponders.
Several retrospective studies to date and one recent prospective study have
documented prevention of HCC after 24 or 48 weeks of therapy with interferon
monotherapy in patients who do not have a sustained viral response. There is
only one published, controlled trial to date using interferon maintenance
therapy and the results demonstrated that continuing interferon for two
years in a subpopulation of nonresponders stabilized fibrosis and reduced
inflammation on serial liver biopsies.
Risk factors for progressive fibrosis
include age >40 years at acquisition of HCV infection, presence of bridging
fibrosis on initial liver biopsy, increased body weight with hepatic
steatosis, excess alcohol consumption >25 g/d, excess hepatic iron, and
immunosuppression. There are no prospective studies that have looked
at concomitant therapy using antifibrotic agents or cytoprotective drugs in
prevention of hepatitis C fibrosis progression. Colchicine and
ursodeoxycholic therapy have no direct antiviral effect, but no data is
available regarding the role of these drugs as long-term therapy in patients
with HCV cirrhosis. Vitamin E has some benefit in reducing ALT levels
in patients with HCV infection, but has not been studied prospectively as an
antifibrotic agent.
Ongoing studies are
planned specifically to examine the role of antiviral therapy on progression
of fibrosis and clinical hepatitis C-related liver disease. There are
two studies that have been launched to evaluate maintenance therapy using
pegylated interferons: the HALT-C trial, sponsored by the NIH, and the
COPILOT (Colchicine vs PegIntron Long-Term), sponsored by Schering Hepatitis
Innovations. Both studies are planning to evaluate the effect of four
years of treatment on the progression of fibrosis and development of liver
failure and/or hepatocellular carcinoma. Together, these studies
should resolve the very important question regarding the role of antiviral
therapy in the natural history of hepatitis C fibrosis.
References
1. Friedman SL. Evaluation of
fibrosis and hepatitis C. Am J Med 107:27S-30S, 1999.
2.
Heathcote EJ, Shiffman ML, Cooksley, et al. Peginterferon alfa-2a in
patients with chronic hepatitis C and cirrhosis. N Engl J Med 343:1673-1680,
2001.
3. Poynard
T, McHutchison J, Davis GL, et al. Impact of interferon alfa-2b and
ribavirin on prgression of liver fibrosis in patients with chronic hepatitis
C. Hepatology 32:1131-1137, 2000.
4. Poynard
T, Ratziu V, Benhamou Y, Di Martino VD, Bedossa P, Opolon P. Fibrosis in
patients with chronic hepatitis C: detection and signficance. Semin Liver
Dis 20:47-55, 2000.
5.
Shiffman ML, Hofmann CM, Contos MJ, et al. A randomized, controlled trial of
maintenance interferon therapy for patients with chronic hepatitis C virus
and persistent viremia. Gastroenterology 117: 1165-1172, 1999.
PEG interferon and
ribavirin reduce liver fibrosis rate in hepatitis C
A combination of pegylated interferon and
ribavirin significantly reduces
the rate of fibrosis progression in patients with hepatitis C, according to
research published in the May issue of Gastroenterology.
A group of international researchers
evaluated the effect of pegylated
(PEG) interferon alfa-2b and ribavirin on liver fibrosis in patients with
chronic hepatitis C.
Individual data from 3010 naive patients,
with pretreatment and
post-treatment biopsies from 4 randomized trials, were pooled.
Ten different regimens combining standard
interferon, PEG interferon, and
ribavirin were compared.
The impact of each regimen was estimated
by the percentage of patients with
at least one grade improvement in the necrosis and inflammation (METAVIR
score).
It was also assessed by the percentage of
patients with at least one stage
worsening in fibrosis METAVIR score, and by the fibrosis progression rate
per year.
Necrosis and inflammation improvement
ranged from 39% (interferon, 24
weeks) to 73% (optimized PEG interferon and ribavirin).
Fibrosis worsening ranged from 23%
(interferon, 24 weeks) to 8% (optimized
PEG interferon and ribavirin).
The team found that all regimens
significantly reduced the fibrosis
progression rates in comparison to rates before treatment.
Furthermore, the reversal of cirrhosis was
observed in 49% of 153 patients
with baseline cirrhosis.
Necrosis and inflammation improved by 73%
with PEG interferon and ribavirin.
Gastroenterology
Six factors were found to be independently
associated with the absence of
significant fibrosis after treatment.
These included baseline fibrosis stage
(odds ratio [OR] = 0.12), sustained
viral response (OR = 0.36), and age less than 40 years (OR = 0.51).
The other associated factors were body
mass index less than 27 kg/m2 (OR =
0.65), no or minimal baseline activity (OR = 0.70), and viral load less
than 3.5 millions copies per milliliter (OR = 0.79).
Professor Thierry Poynard, of the
University of Paris VI, Paris, France,
concluded on behalf of the group, "PEG-interferon and ribavirin combination
significantly reduces the rate of fibrosis progression in patients with
hepatitis C."
In an accompanying Editorial, Professor
Michael J.P. Arthur, of Southampton
General Hospital, England, comments, "The study of Poynard et al.
challenges all of us to accept that the traditional view of cirrhosis as a
progressive, irreversible disease is no longer correct.
"This augurs well for the future of our
patients with chronic HCV
infection, particularly if they clear the virus with treatment," he adds.
"The study also encourages further
scientific investigation of the key cell
and molecular mechanisms of liver fibrosis.
"It raises the prospect that an
antifibrotic agent, aimed at promoting
regression of disease, may be an important therapeutic strategy for the
future," he concludes.
Gastroenterology 2002; 122(5): 1303-13
03 May 2002