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Liz Highleyman
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In This Issue:
Hepatitis C
Genotype 3 HCV May Resolve
Spontaneously
HCV Treatment for Patients on Methadone
Length of Interferon Therapy
Thyroid Disorders Common in People
with HCV
Genotype
3 HCV May Resolve Spontaneously
HCV genotype 3 infection is more likely
to resolve spontaneously than other genotypes, according to
a study published in the July issue of the Journal of
Medical Virology. Heiner Wedemeyer and colleagues studied
92 men with evidence of HCV infection in a German prison.
Among those who had HCV antibodies (indicating that they had
been infected), men with genotype 3 were less likely to have
detectable HCV in their blood compared with genotype 1 patients,
suggesting that the immune system had cleared the virus on
its own. The majority of men infected with genotype 3 HCV
(63%) still developed chronic hepatitis C, but this was significantly
lower than the rate of chronic disease in men with genotype
1 (93%). Because sustained virological response (SVR) rates
using pegylated interferon plus ribavirin are very good in
patients with genotype 2 or 3 HCV—in the range of 75-80%—some
experts recommend that such patients should usually be treated.
However, the authors suggest that given the higher rate of
spontaneous viral clearance, it may be reasonable to wait
before treating those with genotype 3. “Wait and see
for genotype 3, treat immediately for genotype 1,” Wedemeyer
advised.
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HCV Treatment
for Patients on Methadone
Although the latest National Institutes of Health (NIH) consensus
guidelines for the management of hepatitis C recommend that
injection drug users should not automatically be excluded
from HCV therapy, many physicians consider active drug users
and those on opioid substitution therapy to be difficult to
treat. A new German study reported in the July 2004 issue
of Hepatology found that HCV treatment is “reasonably
safe and sufficiently effective” in patients on methadone
maintenance. Stefan Mauss and colleagues studied 100 subjects,
50 on stable methadone maintenance for at least six months
and 50 who had not used illicit drugs or opioid substitution
for at least five years; about 60% in both groups had genotype
1 HCV. All were treated with pegylated interferon (Peg-Intron)
plus ribavirin. During the first eight weeks of treatment,
methadone patients were five times more likely than non-methadone
control subjects to either request to stop HCV therapy or
to discontinue due to nonadherence (22% vs 4%). After eight
weeks, however, rates of discontinuation for these reasons
were similar (10% vs 8%, respectively). Rates of discontinuation
due to side effects or virological failure were somewhat higher
in the methadone group (20% vs 12%), but the difference was
not statistically significant. No serious psychiatric events
occurred in either group, although 15 patients in the methadone
arm and 10 in the non-methadone group took antidepressants
during therapy. End of treatment response rates were 50% in
the methadone group and 76% in the non-methadone arm. After
24 additional weeks of follow-up, the corresponding SVR rates
were 42% and 56%, indicating that the relapse rate was higher
in the non-methadone group. However, since relatively few
patients completed a full course of treatment, the difference
did not reach statistical significance. In a pivotal study
of pegylated interferon/ribavirin, the all-genotype SVR rate
was 56%, similar to that seen in the non-methadone group in
this study. “[T]he control group has a better chance
of treatment response than the group on methadone maintenance,”
wrote the authors, “and this response is driven by increased
compliance and reliability.” Because a substantial proportion
of methadone patients achieved SVR and because most discontinuations
occurred early, thus limiting the cost of unsuccessful therapy—the
results of this study support the NIH recommendation that
hepatitis C patients on methadone maintenance should be offered
therapy.
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Length
of Interferon Therapy
Given the side effects and cost associated with interferon
therapy, HCV patients and researchers are interested in whether
lower doses might be effective. A study in the July 2004 issue
of the American Journal of Gastroenterology suggests
that lower doses of interferon are not as beneficial as higher
doses. Paul Pockros and colleagues treated 639 HCV patients
with thrice-weekly conventional interferon or one of two doses
of once-weekly Pegasys brand pegylated interferon: 135 mcg
or the usual 180 mcg. As expected, patients receiving Pegasys
did better than those receiving conventional interferon. Interestingly,
though, the SVR rates were the same in the 135 mcg and 180
mcg groups (28% for the two Pegasys arms vs 11% for the conventional
interferon arm). But the researchers found that patients in
the 180 mcg Pegasys arm experienced more histological (liver
tissue health) improvement compared with the 135 mcg Pegasys
group (58% vs 48%, compared with 45% for conventional interferon).
This study did not use ribavirin, and the researchers did
not break down their results by genotype in their abstract.
Despite these limitations, the data suggest caution in using
lower doses of pegylated interferon, and indicate that SVR
is not the only important factor to consider when evaluating
the benefits of HCV therapy.
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Thyroid
Disorders Common in People
with HCV
Thyroid disorders are common in people with chronic hepatitis
C, according to a study published in the July 1 issue of the
American Journal of Medicine. Previous research has
shown that 2-20% of people with hepatitis C develop thyroid
dysfunction. Such problems are associated with both HCV infection
itself and with interferon therapy. In this study, Alessandro
Antonelli and colleagues examined the prevalence of thyroid
disorders in 630 subjects. Compared with HCV negative controls,
patients with HCV had higher rates of hypothyroidism (low
production of thyroid hormones) and autoimmune thyroiditis
(a condition in which the body’s own immune system attacks
the thyroid gland). Although the HCV patients had higher levels
of thyroid stimulating hormone (a pituitary gland hormone
that stimulates the thyroid gland), they had significantly
lower levels of free T3 and T4 (two hormones produced by the
thyroid gland). Hypothyroidism was observed in 13% of subjects
with HCV, compared with 3-5% of uninfected control subjects.
In addition, the HCV patients had higher levels of anti-thyroid
antibodies, markers of an autoimmune response. “The
significant association of chronic hepatitis C with hypothyroidism
and thyroid autoimmune phenomena implies that these patients
should be screened for thyroid function on a periodic basis,”
Antonelli recommended. If thyroid hormone levels are found
to be too low, patients can be treated with synthetic supplements.
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