<PAGE> 1
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<PAGE> 2
December 21, 1993
Dear Editor:
Thank you for your interest in abstracts on ribavirin and hepatitis C presented
at the National Liver Association meeting November 4-7, 1993 in Chicago.
For your background and files, please find these abstracts enclosed, as well as
a summary of them along with a background sheet on hepatitis C. Earlier studies
published in Lancet and Hepatology on ribavirin and hepatitis C are also
enclosed. Ribavirin is not yet approved for this indication by the FDA.
Should you have any questions, please feel free to call.
Sincerely,
Jack Sholl
Senior Vice President
Public Relations
enc.
<PAGE> 3
RIBAVIRIN/HEPATITIS CLINICAL ABSTRACTS SUMMARY
* Preliminary results from a study conducted at the National Institutes of
Health's Liver Unit found that capsules of ICN Pharmaceutical Inc.'s
antiviral drug ribavirin (Virazole) may be useful in treating hepatitis C.
Ribavirin was demonstrated to have significant effects on key clinical
parameters. The double blind, placebo-controlled study involves 58 patients
using ribavirin to treat chronic hepatitis C infection. In an abstract
published in Hepatology (Vol. 18, No. 4, pt. 2, 1993) NIH investigators said
initial preliminary results of 32 patients showed that in 16 patients
"...prolonged ribavirin therapy was associated with significant improvement
in serum ALT levels despite unchanged serum HCV RNA levels) and in hepatic
lobular necrosis." The average decrease of liver enzymes in patients taking
ribavirin was 47 percent. The drug was well tolerated; slight, reversible
anemia being the only systematic finding, together with a slight decrease in
T-lymphocytes. Full results await publication.
* A separate study involving 60 patients conducted in Taiwan was
designed to compare the efficacy of combined interferon and ribavirin
(Virazole) therapies versus interferon therapy alone. Among the group
receiving combination therapy, 78 percent of patients had liver enzyme
levels return to normal (they were initially at least two times normal), and
the change was sustained for up to five months. In the group that received
interferon alone, only 33 percent of patients had liver enzyme levels return
to normal (from at least two times normal), and all interferon patients had
a relapse of elevated liver enzyme levels one month after the cessation of
the drug. The combination of interferon and ribavirin (Virazole) was well
tolerated.
* A study conducted in Italy found that the combination of interferon
and ribavirin (Virazole) may benefit patients who were previously
resistant to interferon alone, or who had relapsed after treatment with
interferon. Twenty patients, ten non-respondents and ten patients relapsing
after treatment with interferon, were randomized to either Virazole combined
with interferon, or interferon. After six months of treatment and another
six months of follow-up, the combination induced sustained normalization in
60 percent of patients relapsing after interferon, and 40 percent sustained
normalization in non-responders to interferon. The sustained normalization
of ALT levels was always accompanied by sustained loss of viremia. No
sustained responses were seen in the patients receiving interferon only.
The combination of Virazole and interferon was well tolerated.
(Virazole is authorized in the U.S. in aerosol form for the treatment of
of infants hospitalized with severe lower respiratory tract infection caused
by respiratory syncytial virus. Any other indication or reference in the
U.S. is investigational. Labeling is attached).
<PAGE> 4
FACTS ABOUT HEPATITIS C
* According to the American Liver Foundation, hepatitis C is the second most
prevalent form of hepatitis in the United States. Hepatitis C is a slowly
progressive liver disease that often leads to inflammation of the liver,
cirrhosis, and liver cancer. About 8 to 10 thousand deaths per year can be
attributed to the disease.
* According to the Centers for Disease Control, 150,000 people are infected
with hepatitis C annually. An estimated 1.8 million Americans are already
infected. There are roughly 275,000 cases of active chronic (symptomatic)
hepatitis C.
* Hepatitis C was first identified in 1987, and the first diagnostic test
designed to identify people with the disease was available in 1990. Before
then it was referred to as non-A, non-B hepatitis.
* Most people infected don't develop overt symptoms right away but remain
infectious. The disease is often dormant for decades, making hepatitis C an
invisible epidemic.
* Virtually all individuals infected with hepatitis C will develop active
chronic hepatitis disease (exhibiting some symptoms) or will be chronic
carriers of the virus. Once infected, most patients remain infected for
life.
* It is generally believed that hepatitis C is transmitted through
blood-to-blood contact: blood transfusions and/or intravenous drug use.
There may also exist several unknown modes of transmission.
* The hepatitis C virus differs from other viruses that cause hepatitis, such
as hepatitis A and hepatitis B. Unlike hepatitis C, hepatitis A is
transmitted through food and water contaminated with fecal matter. Similar
to hepatitis C, hepatitis B is transmitted through blood-to-blood contact or
contact with other bodily fluids. Hepatitis B accounts for the majority of
hepatitis cases in the United States.
WHO IS AT RISK?
* The Centers for Disease Control estimate that hepatitis C develops in 1 to 5
percent of people who received multiple blood transfusions.
* It is estimated that up to 80 percent of intravenous drug users admitted to
hospital emergency rooms are infected with hepatitis C.
<PAGE> 5
RIBAVIRIN TREATMENT FOR CHRONIC HEPATITIS C
Olle Reichard Jan Andersson Robert Schvarcz
Ola Weiland
We evaluated oral ribavirin as therapy for chronic hepatitis C infection in a
pilot study including 10 patients. Patients (7 men, 3 women; mean age 40 years,
range 23-54) all had biopsy-proven chronic non-A, non-B hepatitis and were
repeatedly positive for antibodies to hepatitis C virus. Treatment was with
oral ribavirin 1000-1200 mg per day in two divided doses for 12 weeks. The
median serum alanine aminotransferase concentration for all patients at
enrollment was 3.15 ukat/l (range 1.22-7.79) and decreased significantly
(p<0.005) to 1.25 ukat/l (0.78-2.04) after 12 weeks of treatment. Within 6
weeks of the end of treatment the median serum alanine aminotransferase
concentration was not significantly different from that before treatment.
Side-effects were mild and fully reversible after cessation of therapy. We
conclude that ribavirin is the first drug to offer a potentially effective oral
treatment for chronic hepatitis C. It should be further evaluated in
controlled trials, possibly in combination with interferon alpha.
Lancet 1991;337;1058-61.
INTRODUCTION
Hepatitis C virus, an RNA virus similar to the flavivirus and
perstivirus families, has been shown to be the most important setiologic agent
of chronic non-A, non-B hepatitis.(1),(2) Prospective studies indicate that
non-A, non-B hepatitis will develop in about 1-5% of multiple transfused
individuals in the industrialised world.(3),(4) Chronic liver disease will
develop in about half these patients, of whom some 20% will progress to liver
cirrhosis.(3)-(5)
Interferon alpha (IFN alpha) is the only treatment for hepatitis C that
has been evaluated thoroughly. Serum alanine aminotransferase (ALT)
concentrations return to normal in about 50% of patients receiving long-term
treatment with subcutaneous IFN alpha.(6),(7) However, after treatment ceases,
ALT concentrations remain normal in only 10-20% of patients.(6),(7)
________________________________________________________________________________
ADDRESSES: Departments of Infectious Diseases, Karolinska Institute, Danderyds
Hospital (O. Relchard, MD, J. Andersson, MD, PhD), and Roslagstulls Hospital
(R. Schvarcz, MD, O. Weiland, MD, PhD), Stockholm, Sweden, Correspondence to
Dr. Ola Weiland, Department of Infectious Diseases, Karolinska Institute,
Roslagstulls Hospital, Box 5651, 114 89, Stockholm, Sweden.
________________________________________________________________________________
<PAGE> 6
VOL 337: MAY 4, 1991 1059
- -------------------------------------------------------------------------------
[CHART]
FIG 1 -- CHANGE IN MEDIAN ALT CONCENTRATIONS IN 10 PATIENTS TREATED WITH
RIBAVIRIN.
The box shows the 25th through 75th percentile, the bar within the box
the 50th percentile, the upper and lower bars the 90th and 10th percentile,
respectively. 5-12 months before treatment (II), 3-10 weeks before treatment
(I): *p < 0.005, **not significant, Wilcoxon signed rank test.
Ribavirin (1-B-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) is a
non-interferon-inducing nucleotide analogue with a broad spectrum of activity
against RNA and DNA viruses, including those from the flavivirus family.(8)(9)
The drug has often been used as an aerosol to treat respiratory syncytial virus
infections, but has not been used extensively in other viral infections because
of reports of teratogenic and/or embryolethal effects in rodents and
rabbits,(10) although no teratogenicity has been seen in baboons.(10) It is
not thought to have mutagenic or carcinogenic effects.(11) Trials of oral
ribavirin therapy have been done in patients infected with human
immunodeficiency virus,(12) hepatitis B virus,(13) and Lassa fever virus.(14)
We therefore designed a pilot study to evaluate the clinical benefits and side
effects of oral ribavirin treatment in patients with chronic hepatitis C.
PATIENTS AND METHODS
Patients were entered into the trial if they had biopsy finding
consistent with a diagnosis of chronic non-A, non-B hepatitis and were
repeatedly positive for antibodies to hepatitis C virus by enzyme-linked
immunosorbent assay ('Ortho-HCV', Ortho Diagnostic Systems). 7 men and 3 women
- -- mean age 40 years (range 23-54) -- met the criteria and were included in the
study. 4 patients had acquired hepatitis from intravenous drug abuse, 5 from
blood transfusions, and 1 had no known source of infection. All patients had
raised serum ALT concentrations for a minimum of 12 months before study entry.
No patients had markers for hepatitis B virus infection or human
immunodeficiency virus infection, or alcoholic, drug-related, autoimmune, or
metabolic liver disease, and none had received antiviral or immunomodulatory
therapy within the 6 months before study entry. Prestudy liver biopsy showed
that half the patients had chronic active hepatitis (CAH) and half had chronic
persistent hepatitis (CPH). The trial was approved by the
[CHART]
FIG 2 -- CHANGE IN ALT CONCENTRATIONS FOR INDIVIDUAL PATIENTS WITH CAH (A) AND
CPH (B) BEFORE, DURING, AND AFTER TREATMENT WITH RIBAVIRIN.
5-12 months before treatment (II), 3-10 weeks before treatment (I)
<PAGE> 7
ethical committee at the Karolinska Institute, and all patients gave informed
verbal consent.
All patients were treated with two doses per day of oral ribavirin (ICN
Pharmaceuticals, California, USA) for 12 weeks at 1000 mg/day for patients
weighing 55-75 kg and 1200 mg/day for patients weighing more than 75 kg. Side
effects were monitored by questioning and examination. Haemoglobin, white
cells, platelets, differential blood cell counts including granulocyte counts,
serum uric acid, and serum creatininc were measured before the start of therapy
and at weeks 1, 3, 5, 7, 9, and 12 during treatment and weeks 1, 2, 6, and 12
post-treatment. Serum albumin was determined before treatment started and 12
weeks after treatment finished. Statistical analyses were done with the
Wilcoxon signed rank test.
RESULTS
Biochemical response to ribavirin
Serum ALT concentrations decreased in all patients during ribavirin
therapy, but increased to pretreatment concentrations after treatment coded
(fig 1, fig 2). The median serum ALT concentration for all patients at
enrolment was 3.15 ukat/l (range 1.22-7.79) and decreased significantly
(p<0.005) to 1.25 ukat/l (range 0.78-2.04) by the end of treatment. The median
ALT concentration 6 weeks after cessation of treatment (2.48 ukat/l, range
0.7-5.26) was not significantly different from the pretreatment value (fig 1).
Between weeks 0 and 12 of ribavirin therapy, median ALT concentrations
decreased significantly from 3.28 ukat/l (2.28-7.79) to 1.32 ukat/l (0.78-2.04)
in patients with CAH (p<0.04), and from 1.78 ukat/l (1.22-3.68) to 1.0 ukat/l
(0.9-1.55) in patients with CPH (p<0.04). 6 weeks after cessation of
treatment, median serum ALT concentrations were 2.32 ukat/l (1.71-5.26) and
2.64 ukat/l (0.7-3.42) for patients with CAH and CPH, respectively, and not
significantly different from pretreatment concentrations.
The biochemical findings before, during, and after ribavirin treatment
are shown in the table. A decrease in mean serum haemoglobin during treatment
was seen. The fall was most notable from treatment weeks 1-5 after which
haemoglobin concentration stabilized. Serum uric acid concentrations rose
slightly during treatment, but no changes were seen in white blood cell and
differential blood cell counts, platelet count, serum albumin, and prothrombin
time (table). Haemoglobin and serum uric acid became normal 6 weeks after
treatment.
Side effects
Adverse reactions were mild and fully reversible after cessation of
therapy, 6 of the 10 patients had no side effects, 1 patient had myalgia, 1 had
nausea, 1 had fatigue not necessitating dose changes, and 1 patient experienced
itching on the last day of treatment and a few days thereafter. The same
patient's haemoglobin fell from 156 g/l at week 0 to 117 g/l at week 12, after
which haemoglobin rose spontaneously to pretreatment concentrations.
DISCUSSION
Although hepatitis C virus infection is usually a subclinical disease
in its acute phase, its propensity to progress to chronic hepatitis, cirrhosis,
and, possibly, hepatocellular carcinoma means that effective treatment must be
sought. The major drawbacks of IFN alpha therapy are prolonged parenteral
treatment schedules and the fact that most patients who respond relapse after
treatment withdrawal.(6,7)
Since oral ribavirin treatment is tolerated in patients with other
virus infections,(12-14) it seemed reasonable to try this therapy in patients
with chronic hepatitis C infection. In our study, serum ALT concentrations
were significantly reduced during oral ribavirin therapy of 10 patients with
chronic hepatitic C virus infection and this effect was probably caused by the
antiviral properties of ribavirin.(8,9) Ribavirin treatment was well tolerated
with few side effects (table). The favourable effect on serum ALT
concentrations was, although not sustained after treatment cessation, similar
to that seen with IFN alpha therapy.(6,7) Ribavirin is, however, the first
drug to offer a potentially effective oral treatment for chronic hepatitis C
virus infection.
This pilot study seems to demonstrate an antiviral effect of ribavirin
in individuals with chronic hepatitis C virus infection, even if the mechanism
of action is not known. Combination therapy with IFN alpha may cure
individuals of chronic hepatitis C virus infection, and this combination should
be evaluated in future trials.
MEAN OF MEDIAN (RANGE) LABORATORY FINDINGS IN 10 PATIENTS
WITH CHRONIC HEPATITIS C TREATED WITH RIBAVIRIN
<TABLE>
<CAPTION>
WEEKS FROM START OF TREATMENT
PRE- ----------------------------------------------------------
- TREATMENT 5 12* 18 24
- ----------- ----------- ----------- ----------- -----------
<S> <C> <C> <C> <C> <C>
Median ALT+ 3.15 1.5 1.25 2.48 2.92
(ukat/l) (1.22-7.79) (0.72-2.65) (0.78-2.04) (0.70-5.26) (1.21-5.86)
Mean
haemoblobulin 150 134 132 149 150
(g/l) (133-172) (117-159) (110-157) (133-171) (121-175)
Mean bilirubin 11-2 10 13 9 11
(mmol/l) (6-16) (6-26) (7-21) (1-22) (2-19)
Mean uric acid 286 301 320 262 248
(mmol/l) (201-372) (185-447) (261-465) (167-364) (144-356)
Mean white
blood cell count 6.1 5.7 5.0 5.5 5.4
(x 10/l) (4.4-8.0) (3.8-7.9) (4-7.1) (4.1-6.7) (4.4-6.7)
Mean
granulocyte 3.2 3.3 2.9 3.1 3.0
count (x 10/l) (1.9-4.5) (1.9-5.5) (2.1-4.5) (1.8-4.4) (2-4.2)
Mean platelet 245 272 257 245 225
count (x 10/l) (141-341) (155-405) (160-368) (150-319) (114-326)
Mean albumin 41.7 .. 41.1 .. 42.7
(g/l) (37-46) (39-44) (38-48)
Mean
prothrombin 87 83 86 91 87
time(s) (68-130) (70-103) (66-123) (71-126) (72-122)
</TABLE>
* End of treatment.
+ Upper limit of normal=0.7 ukat/l.
REFERENCES
1. Choo Q, Kuo G, Weiner A, Overby L, Bradley D, Houghton M. Isolation of
a cDNA clone derived from a blood-borne non-A, non-B viral hepatitis
genome. Science 1989; 244: 359-62.
2. Kuo G, Choo QL, Alter HI, et al. An essay for circulating antibodies
to a major etiologic virus of human non-A, non-b hepatitis. Science
1989; 244; 362-64.
3. Mattesson L, Aberg B, Weiland O, Sellman M, Davilen J. Non-A, non-B
hepatitis after open-heart surgery in Stockholm; declining incidence
after introduction of restrictions for blood donations due to the human
immunodeficiency virus. Scand J Infect Dis 1988; 20: 371-76.
4. Van der Poel CL, Reesink HW, Lelie PN, et al. Anti-hepatitis C
antibodies and non-A, non-B post-transfusion hepatitis in the
Netherlands. Lancer 1989; ll: 297-98.
5. Mattesson L, Weiland O, Glaumann, H. Long-term follow up of chronic
posttransfusion non-A, non-B hepatitis; clinical and histological
outcome. Liver 1988; 8: 184-88.
6. Davis GL, Balatt LA, Schiffer, et al. treatment of chronic hepatitis C
with recombinant interferon alpha. A multicenter randomized,
controlled trial, N Engl J Med 1989; 321; 1501-06.
7. Di Bisceglie AM, Martin P, Kassianides C, et al. Recombinant interferon
alpha therapy for chronic hepatitis C. A randomized, double-blind,
placebo-controlled trial, N Engl J Med 1989; 321: 1506-10.
8. Sidwell R, Hoffman J, Kharp L, et al. Broad-spectrum activity
<PAGE> 8
of virazole; 1-beta-D-ribofuranosyl1,2,4-triazole-3-carboxamide, Science
1972; 117; 705-06.
9. Patterson JL, Fernandez-Larson. R. Molecular action of ribavirin, Rev.
Infect Dist 1990; 12; 1132-46.
10. Canonico PG, Kends M, Huggins JW. The toxicology and pharmacology or
ribavirin in experimental animals. In: Smith RA, Knight V, Smith JAD, eds.
Clinical application of ribavirin, Orlando, Florida; Academic Press, 1984;
79-92.
11. Johnson EM. The effects of ribavirin on development and reproduction-a
critical review of published and unpublished studies in experimental
animals. I Am Call Toxical 1990; 9: 114-19.
12. Roberts RB, Jurica K, Meyer 111 WA, Paxton H, Makuch R. A phase I study
of ribavirin in human immunodeficiency virus infected patients. I Infect
Dis 1990; 162; 638-42.
13. Patki S, Gupta P. Evaluation of ribavirin in the treatment of secure
hepatitis. Chemotherapy 1982; 28: 298-303.
14. McCormick JB, King IJ, Webb PA, et al. Lasto fever-effective theraphy with
ribavirin. N Eng I Med 1986; 314: 20-26.
Consent of publication has not been received from The Lancet as of the
date of this filing.
<PAGE> 9
A PILOT STUDY OF RIBAVIRIN THERAPY
FOR CHRONIC HEPATITIS C
ADRIAN M. DI BISCEGLIE,(1)
MICHIKO SHINDO,(1)
TSE-LING FONG,(1)
MICHAEL W. FRIED,(1)
MARK G. SWAIN,(1)
NORA V. BERGASA,(1)
CONSTANTINE A. AXIOTIS,(2)
JEANNE G. WAGGONER,(1)
YOON PARK(1)
and
JAY H. HOOFNAGLE(1)
1 Liver Disease Section, National Institute of Diabetes and Digestive
and Kidney Diseases, and 2 Office of the Director, Clinical Center,
National Institutes of Health, Bethesda, Maryland 20892
------------
Reprinted from
HEPATOLOGY
St. Louis
------------
Vol. 16, No. 3, pp. 649-654, September, 1992
(Copyright C 1992, by The American Association for
the Study of Liver Diseases)
(Printed in the U.S.A.)
<PAGE> 10
A PILOT STUDY OF RIBAVIRIN THERAPY FOR CHRONIC HEPATITIS C
Adrian M. Di Bisceglie,(1) Michiko Shindo,(1) Tse-Ling Fong,(1)
Michael W. Fried,(1) Mark G. Swain,(1)
Nora V. Bergasa,(1) Constantine A. Axiotis,(2) Jeanne G. Waggoner,(1)
Yoon Park(1) and Jay H. Hoofnagle(1)
(1) Liver Disease Section, National Institute of Diabetes and Digestive
and Kidney Diseases, and (2) Office of the Director, Clinical Center,
National Institutes of Health, Bethesda, Maryland 20892
INTERFERON-ALPHA THERAPY IS OF PROVEN EFFICACY IN CHRONIC HEPATITIS C,
BUT IT IS NOT UNIVERSALLY EFFECTIVE AND MAY BE ASSOCIATED WITH INTOLERABLE SIDE
EFFECTS. RIBAVIRIN IS A NUCLEOSIDE ANALOG WITH A BROAD SPECTRUM OF ANTIVIRAL
ACTION. WE CONDUCTED AN UNCONTROLLED PILOT STUDY OF RIBAVIRIN THERAPY IN 13
PATIENTS WITH CHRONIC HEPATITIS C. RIBAVIRIN WAS GIVEN FOR 6 MO, IN A DOSE
THAT WAS INCREASED, AT 2-MO INTERVALS, FROM 600 MG TO 1,000 MG TO 1,200 MG/DAY.
SERUM ALT LEVELS GRADUALLY DECREASED IN ALL 13 TREATED PATIENTS; THE MEAN
PERCENTAGE OF DECREASE WAS 67% (FROM 210 U/L [RANGE = 109 TO 593] TO 63 U/L
[RANGE = 22 TO 108 U/L]; P = 0.0006) AFTER 6 MO OF TREATMENT. SERUM
AMINOTRANSFERASE LEVELS FELL TO THE NORMAL RANGE IN FOUR PATIENTS (31%). IN
THE 3 TO 6 MO AFTER CESSATION OF RIBAVIRIN THERAPY, SERUM AMINOTRANSFERASE
ACTIVITIES GRADUALLY ROSE TO NEAR PRE-TREATMENT LEVELS IN ALL BUT ONE PATIENT.
THERAPY WAS ASSOCIATED WITH A SIGNIFICANT DECREASE IN THE GEOMETRIC MEAN TITER
OF HEPATITIS C VIRUS RNA IN SERUM (1:1,981 VS. 1:199; P LESS THAN 0.02)
ALTHOUGH NO PATIENTS LOST HEPATITIS C VIRUS RNA FROM SERUM DURING THERAPY. NO
SIGNIFICANT IMPROVEMENT WAS SEEN IN LIVER HISTOLOGICAL APPEARANCE. RIBAVIRIN
THERAPY RESULTED IN MILD, REVERSIBLE HEMOLYSIS; NO PATIENT EXHIBITED
SYMPTOMATIC ANEMIA. THESE FINDINGS SUGGEST THAT RIBAVIRIN HAS A BENEFICIAL
EFFECT IN PATIENTS WITH CHRONIC HEPATITIS C, ALTHOUGH FURTHER STUDIES ARE
NEEDED TO DETERMINE HOW RIBAVIRIN IS BEST USED. (HEPATOLOGY 1992;16:649-654.)
Chronic hepatitis C is typically an insidious and slowly progressive
disease. In some patients, cirrhosis and even HCC develop (1-3). This disease
is caused by chronic infection with the hepatitis C virus (HCV), which was
recently identified as a single-stranded RNA virus. Specific tests are now
available for detection of antibody to HCV (anti-HCV) and for the nucleic acid
of the agent (4, 5). Recently interferon-alpha was shown to be effective in
decreasing the level of hepatocellular injury and inflammation in patients with
chronic hepatitis C (6, 7). Unfortunately, interferon is not universally
effective, and its usefulness is often limited by side effects such as fatigue,
depression, bone marrow suppression or autoimmune thyroid disease (8). It is
clear that safer and more effective treatments that interfron for chronic
hepatitis C should be sought.
Ribavirin (1-beta-D-ribofuranosyl-1H-1,2,4-triazole-3-carboxamide) is a
nucleoside analog with a broad spectrum of antiviral activity against RNA
viruses, including some agents that resemble HCV (9). We report the results of
a preliminary study of 13 patients with chronic hepatitis C infection who
underwent 6 mo of therapy with ribavirin.
________________________
Received December 3, 1991; accepted April 28, 1992.
Address reprint requests to: Adrian M. Di Bisceglie, M.D., Liver Diseases
Section, NIH Bldg. 10 Rm 4D 52, Bethesda, MD 20892.
31/1/39158
PATIENTS AND METHODS
Adult patients with chronic hepatitis C infection and anti-HCV in serum
or histories of parenteral exposure to blood or blood products were eligible
for this study. Patients were included if they had persistently elevated serum
aminotransferase activities for at least 6 mo and the serum ALT level was at
least twice the upper limit of the normal range on two separate occasions (at
least 1 mo apart) before therapy. Only patients with compensated liver disease
who had no other serious medical illnesses and no evidence of liver disease
other than hepatitis C were included. Patients with HBsAg or antibody to
human immunodeficiency virus (anti-HIV) in serum were excluded.
After evaluation and percutaneous liver biopsy, patients were given
ribavirin (Viratek, Inc., Costa Mesa, CA) orally in two daily doses. The
medication was given for 6 mo, starting at 600 mg/day and increasing after 2 mo
to 1,000 mg/day. After another 2 mo, the dose of ribavirin was increased to
1,200 mg/day in those patients whose serum ALT values were not yet normal or
near normal (less than 1.5 times the upper limit of normal). Compliance with
therapy was monitored by means of patient diaries. Patients were examined and
had blood samples taken weekly for the first month and then monthly for the
duration of treatment and the following 6 mo. Thereafter, patients were
evaluated at 3-mo intervals. On each occasion, blood was tested for complete
blood counts; routine serum biochemical function tests, including those for
serum aminotransferase activities, were also performed. Liver biopsy was
repeated after 6 mo of treatment. Histological changes associated with
treatment were assessed by two reviewers (CAA and AMD), who examined
pretreatment and posttreatment liver biopsy samples under code.
Liver biopsy specimens were stained with hematoxylin and sosin and by
Masson's trichrome method. The degrees of necroinflammatory change and
portal-portal bridging were evaluated with the scale developed by Knodell et
al. (10). In addition, all specimens were ranked from least to most severe
current hepatic injury, as described previously (7). The degree of current
hepatic injury was judged after assessment of the
<PAGE> 11
Fig. 1. Mean percentage change in serum ALT values during and
after 6 mo of therapy with ribavirin.
degree of periportal (piecemeal) necrosis, portal inflammatory infiltrate,
bridging and intralobular hepatocellular necrosis.
Initial serum samples were tested for anti-HCV by ELISA (HCV ELISA;
Ortho Diagnostic Systems, Raritan, NJ). Serum samples taken at 3-mo intervals
were tested for HCV RNA by the "double" polymerase chain reaction method with
"nested" oligonucleotide primers from the highly conserved 5' noncoding
region of the genome as previously described (11, 12). Each assay included two
serum samples from healthy normal volunteers known to be negative for HCV RNA
(as controls). The amount of HCV RNA detected was quantitated by performing
serial 10-fold dilutions of extracted RNA before polymerase chain reaction and
by estimating a titer of HCV RNA by end-point dilution. Anti-HIV was tested
with an ELISA (Abbott Laboratories, North Chicago, IL), and HBsAg and antibody
to HBcAg were tested by RIA (AUSRIA II and Corab; Abbott Laboratories).
The details of this treatment protocol were approved by the
Institutional Clinical Research Subcommittee of the National Institute of
Diabetes and Digestive and Kidney Diseases; all patients gave written informed
consent for the study. The effects of ribavirin on chronic hepatitis C
infection were assessed from changes in serum aminotransferase activities,
HCV RNA titers and liver histopathological appearance. These changes were
compared by paired Student's t test for statistical significance.
RESULTS
Thirteen patients were treated (Table 1). They comprised 10 men and 13
women with a mean age 44 yr (range = 32 to 66 yr) and a mean known duration of
chronic hepatitis of 8.8 yr (range = 1.2 to 18 yr). The sources of hepatitis
was presumed to be intravenous drug abuse in seven patients (54%) and blood
transfusion in four patients (31%); source was unknown in two patients (15%).
Anti-HCV was detectable in 12 patients (92%) and HCV RNA was found in all 13
patients before treatment. Liver biospy specimens taken before treatment showed
CAH in nine patients (69%) and active cirrhosis in four patients (31%).
Serum ALT activities decreased progressively during therapy in all
patients (Fig. 1). The decrease in ALT was gradual; by 2 mo, the mean
percentage decrease in ALT values was 37%; after 4 mo it was 61% and by the end
of therapy (6 mo) it was 67% (Table 2). Serum ALT values became normal during
therapy in four patients (31%) after 8 wk in two patients, after 12 wk in 1
patient and after 24 wk in another patient. Serum AST activities followed a
similar pattern.
The dose of ribavirin was increased to 1,200 mg/day after 4 mo of
treatment in seven patients. In one case the dose was not increased, despite a
serum ALT of 75 U/L at 4 mo, because of concerns about anemia in the patient.
All 13 patients were followed for at least 12 mo after stopping
ribavirin therapy. Serum aminotransferase activities rose in all but one
patient after discontinuation of therapy, usually approaching pretreatment
levels within 2 to 3 mo (Fig. 1). The course of a typical respone is shown in
Figure 2. One patient appeared to have a long-term response, with normal serum
aminotransferase activities persisting for at least 15 mo after the drug was
stopped.
HCV RNA remained detectable in serum in all patients throughout the
trial and follow-up. The geometric mean titer of HCV RNA decreased from 1:2,424
to 1:203 after 6 mo of therapy (p < 0.02) (Table 3, Fig. 3). Interestingly,
although the serum aminotransferase levels had risen in most cases within 3 mo
of cessation of ribavirin therapy, levels of HCV RNA did not rise immediately
after cessation of therapy and in some cases fell further. However, mean HCV RNA
levels had risen to pretreatment levels by 6 mo after cessation of ribavirin
therapy.
Comparison of pretreatment and posttreatment liver biopsy samples
showed that neither the mean histologicl activity index nor the current
hepatic injury ranking decreased with therapy. The mean histological activity
index was 12.9 before and 13.8 after treatment,
<PAGE> 12
Vol. 16, No. 3, 1992
RIBAVIRIN FOR HEPATITIS C
[CHART]
Fig. 2. Serial changes in serum ALT activity and HCV RNA titer in a
patient with chronic hepatitis C infection treated with ribavirin. The
aminotransferase values became normal after 8 wk; levels of HCV RNA in serum
decreased, but the viral gonome was still detectable throughout therapy.
TABLE 1. PRETREATMENT SEROLOGICAL AND SERUM BIOCHEMICAL
CHARACTERISTICS OF 13 PATIENTS WITH CHRONIC HEPATITIS C
INFECTION TREATED WITH RIBAVIRIN
<TABLE>
<CAPTION>
MEAN
FEATURE VALUE NO. RANGE PERCENTAGE
------- ----- --- ----- ----------
<S> <C> <C> <C> <C>
Serum ALT (U/L) 210 -- 109-593 --
Serum AST (U/L) 132 -- 66-261 --
Serum bilirubin (mg/dl) 1.0 -- 0.4-2.4 --
Prothrombin time (sec) 12.4 -- 11.6-14.6 --
Anti-HCV positive -- 12 -- 92
HCV RNA positive -- 13 -- 100
Anti-HBc positive -- 5 -- 38
</TABLE>
Anti-HBc = antibody to HBcAg.
and the mean current hepatic injury rankings were 13.9 vs. 13.1, respectively.
The most prominent side effect of therapy was mild hemolytic anemia
(Fig. 4). The mean hematocrit level decreased from 42.8% to 38.2% (mean
decrease = 11%; p less than 0.00007). The mean reticulocyte count rose from
2.1% to 5.6% (p less than 0.0007), and bilirubin values rose from 0.92 mg/dl to
1.43 mg/dl (p less than 0.009). No patient experienced symptomatic anemia.
Serum haptoglobin levels fell in all but three patients and became undetectable
in six. The only patient who had no evidence of hemolysis during ribavirin
therapy had had a splenectomy.
One patient with a previous history of gout experienced acute podagra
associated with hyperuricemia during the third month of therapy. However, the
overall mean uric acid levels in the 13 patients did not change significantly
during ribavirin therapy (5.9 mg/dl before therapy vs. 6.3 mg/dl at the end of
therapy).
DISCUSSION
Interferon-alpha has been shown to be effective and is now licensed for
use in treatment of chronic hepatitis C in the United States. In approximately
50% of cases, interferon therapy is associated with a rapid decrease in serum
aminotransferases to normal, an improvement in liver histopathological
appearance and the disappearance of HCV RNA in serum (6, 7, 13). However,
patients with hepatitis C often relapse after stopping interferon, and
interferon treatment may be associated with clinically significant side
effects.
[CHART]
Fig. 3. Serial changes in mean titers of HCV RNA during and after
therapy with ribavirin. Levels decreased significantly by the end of therapy
and remained suppressed for at least 3 mo after therapy.
Ribavirin is a nucleoside analog agent with a broad spectrum of
antiviral activity. Although its mechanism of action remains uncertain, it
appears to inhibit the replication of RNA viruses in cell culture by inhibiting
viral RNA-dependent RNA polymerase, by depleting intracellular guanine pools
and by interfering with the "capping" of viral RNAs (9). Ribavirin therapy is
of proven benefit against several RNA viruses that infect human beings,
including respitatory syncytial virus infections in children and certain viral
hemorrhagic fevers (14, 15). In a preliminary study, Reichard and coworkers
found that ribavirin, when administered for 12 wk to patients with chronic
hepatitis C, was associated with a significant decline in serum aminotrans-
<PAGE> 13
HEPATOLOGY
DI BISCEGLIE ET AL
TABLE 2. CHANGES IN SERUM ALT ACTIVITIES AFTER RIBAVIRIN THERAPY FOR 6 MO
IN 13 PATIENTS WITH CHRONIC HEPATITIS C INFECTION
<TABLE>
<CAPTION>
ALT (U/L)
------------------------------------------------------------------------------------
BEFORE AFTER 3 MO OF AFTER 6 MO OF 3 MO AFTER 6 MO AFTER
PATIENT NO. TREATMENT TREATMENT TREATMENT TREATMENT TREATMENT
- ----------- --------- ------------- ------------- ---------- ----------
<S> <C> <C> <C> <C> <C>
1 208 95 71 256 121
2 252 121 74 102 189
3 171 45 69 438 131
4 177 37 22 39 49
5 593 136 99 277 303
6 82 45 36 39 60
7 151 54 54 200 179
8 181 123 79 134 114
9 153 76 24 136 49
10 124 37 41 63 85
11 115 61 58 148 96
12 214 121 108 295 190
13 305 139 86 325 316
Mean 210 84(a) 63(b) 188 145(c)
</TABLE>
(a) p less than 0.005.
(b) p less than 0.0005.
(c) p less than 0.01.
TABLE 3. CHANGES IN SERUM HCV RNA LEVELS AFTER RIBAVIRIN THERAPY
IN 18 PATIENTS WITH CHRONIC HEPATITIS C INFECTION
<TABLE>
<CAPTION>
HCV RNA (RECIPROCAL TITER)
------------------------------------------------------------------------------------
BEFORE AFTER 3 MO OF AFTER 6 MO OF 3 MO AFTER 6 MO AFTER
PATIENT NO. TREATMENT TREATMENT TREATMENT TREATMENT TREATMENT
- ----------- --------- ------------- ------------- ---------- ----------
<S> <C> <C> <C> <C> <C>
1 10,000 1,000 1,000 100 100
2 1,000 100 10 10 1,000
3 100 100 1,000 100 10,000
4 10,000 10,000 10 100 10,000
5 1,000 10,000 1,000 10,000 1,000
6 10,000 10,000 10,000 100 10,000
7 1,000 1,000 1,000 1,000 100,000
8 1,000 1,000 1,000 1,000 1,000
9 1,000 1,000 100 100 1,000
10 10,000 100 10 100 1,000
11 1,000 10,000 10 10 1,000
12 10,000 1,000 100 100 10,000
13 10,000 1,000 1,000 1,000 10,000
GMT 2,424 1,194 203 170 2,894
</TABLE>
GMT = geometric mean titer. The HCV RNA end-point dilution titer is
determined by detecting HCV RNA in serial dilutions of RNA from 6.25 micron l
serum.
ferase activities (16). We therefore tested the effect of ribavirin for a
longer period (24 wk) and evaluated changes in HCV RNA and liver
histopathological appearance and serum aminotransferases.
In this pilot study, ribavirin therapy was associated with a significant
decrease in serum aminotransferases and levels of HCV RNA. In contrast to the
type of response seen with interferon, the decrease in aminotransferase
activities associated with ribavirin was more gradual. Thus, with interferon,
the maximal decrease in mean ALT values (70%) was noted after 1 mo of therapy,
wherease with ribavirin the maximal decrease (67%) occurred after a full 6 mo of
therapy. Interestingly, serum ALT activities decreased by at least 50% in all
treated patients, wherease up to 50% of patients treated with interferon had no
decreases in serum aminotransferases at all (6, 7, 13). Although the mean titer
of HCV RNA among all patients fell during therapy, RNA levels did not decrease
at all in five patients even though their serum aminotransferase levels were
lower after therapy.
No improvement was noted in the histological severity of the hepatitis
after 6 mo of therapy. This may have been related to the relatively slow decline
in serum aminotransferase levels and the fact that the HCV genome did not
disappear from serum. Alternatively, the improvement in ALT documented in this
study may not truly reflect improvement in the underlying liver disease.
Perhaps longer courses of therapy with biopsy specimens taken after several
months of maximal
<PAGE> 14
decrease of serum aminotransferases will reveal a beneficial effect of
ribavirin in chronic hepatitis C infection.
RIBAVIRIN FOR HEPATITIS C
Vol. 16, NO. 3, 1992
(CHART)
Fig. 4. Mean percentage changes in hematocrit values, reticulocyte
counts and total serum bilirubin concentrations during ribavirin therapy in 13
patients with chronic hepatitis C infection.
The fact that the serum aminotransferase levels began to rise again
after cessation of ribavirin therapy confirms that HCV infection was not
completely eliminated. However, HCV RNA levels may have remained suppressed
for several months after ribavirin therapy ended because of the relatively long
half-life of ribavirin in serum (approximately 29 hr)(17).
The hemolysis associated with ribavirin was reversible and not
clinically significant in any patient. The mechanism by which ribavirin causes
hemolysis remains uncertain but may be related to its accumulation in RBCs. The
observation that ribavirin was well tolerated suggests that ribavirin can be
given for prolonged periods. Ribavirin has been reported to be teratogenic in
rats, with decreased postnatal survival in pups born to rats treated with very
high doses of ribavirin (90 mg/kg/day). No significant teratogenic effects were
noted in rabbits or baboons treated similarly (18). No reports have been made
of teratogenicity in human subjects treated with ribavirin during pregnancy
(Fernandez H. Viratek, Inc., Personal communication, 1991). However, the use of
ribavirin should be avoided in pregnancy.
In concthe results of this pilot study of ribavirin therapy in chronic
hepatitis C infection suggest that ribavirin has significant antiviral activity
against HCV. Ribavirin therapy was very well tolerated, and no patient had
clinically significant side effects. The role of long-term therapy (>6 mo) in
inducing prolonged remission of hepatitis C with histological improvement
should be explored further.
Acknowledgments: We gratefully acknowledge Dr. Myron Tong and Dr. Leon
Lewandowski for helpful discussions about the use of ribavirin for chronic
hepatitis C infection and Viratek, Inc., for supplying ribavirin.
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Consent of publication has not been received from Hepatology as of the
date of this filing.
