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PegIntron and Ribavirin in African-Americans and Caucasians; preliminary
report
Reported by Jules Levin
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Previous studies have suggested lower response rates for African-Americans
treated with interferon based regimens for HCV. The higher prevalence of
genotype 1 has been suggested as a potential explanation for the lower
response rates. One study (McHutchison, Gastroenterology 2000) found white
and black patients with genotype 1 had similar SV response rates (22-23%).
The goal of this study is to compare the sustained virologic response rates
of African-Americans and non-hispanic whites with HCV treated with
PegIntron+RBV.
Andrew Muir (Southeatern Hepatitis Treatment Group, Durham, NC) reported in
an oral presentation the preliminary results of this study conducted at 17
community and university gastroenterology and hepatology clinics.
100 African-American and 100 non-hispanic whites with no prior HCV treatment
are enrolled. They have compensated liver disease (less advanced) and both
study groups are balanced for genotype. Patients receive PegIntron 1.5 mcg/kg
weekly plus ribavirin 1000mg day for 12 weeks followed by 800 mg/day for 36
weeks.
Patients are being followed for sustained virologic response, histologic
response, and health related quality of life.
Among the baseline characteristics that are different between the whites and
blacks: the African-Americans are heavier in weight (89.0 kg vs 81.6 kg,
p<0.05). A kg is 2.2 lbs so the African-Americans are about 16 pounds
heavier. Weight is a factor in treatment outcome. Heavier patiens tend not to
respond as well to therapy. The other baseline patient characteristics were
about the same for the whites and blacks: 67% male, 44-47 years of age, 19
years duration of HCV, 98% genotype 1a or 1b, 47-53% >2 million copies of HCV
viral load, and 6% had cirrhosis.
More whites got HCV in this study through transfusion (26% vs18%). More
blacks got HCV through IVDU (52% vs 43%). Alcohol use 35% blacks vs 30%
whites. More blacks have hypertension (46% vs 12%), diabetes (23% vs 6%) and
more whites have depression (32% vs 16%).
PRELIMINARY VIROLOGIC RESPONSES
After 12 weeks of therapy, 58% of the whites were HCV-RNA negative compared
to 28% of the blacks. 69% of the whites had a 2 log drop in viral load vs 40%
of the blacks, after 12 weeks of therapy.
After 24 weeks of therapy, 62% of whites had virologic response vs 25% of the
blacks (p<0.0001). After 24 weeks about 70% of the whites and 42% of the
blacks had an ALT response.
Dose reductions: among blacks 9% reduced PegIntron dose, 4% reduced RBV dose;
among whites 6% reduced Peg dose, 3% reduced RBV dose. 19% of blacks
discontinued vs 21% of whites. The side effects profile was about the same
for whites and blacks, although 3% of blacks experienced anemia vs 0% of
whites, and 0% of blacks experienced thrombocytopenia vs 2% of whites.
The authors concluded that these study results suggest a lower response rate
among African-Americans compared to whites. And since all patients had
genotype 1 this difference in response is not due to being genotype 1. These
findings suggest the need for continued research examining the explanation
for the lower response rates among African-Americans. The NIH is conducting a
study now exploring these questions.
These study results are preliminary, and the histologic responses have not
been reported yet. Itıs important to remember that this study examines the
viral response to therapy. A secondary goal of therapy is to slow disease
progression. A number of studies have found that even patients with no viral
load response can slow disease progression with interferon therapy. This can
be an important accomplishment since there is much research going on now into
new drugs for HCV and it is expected that there will be new drugs for HCV in
several years. But for some patients it is important to consider slowing
disease progression, particularly for HCV/HIV coinfected patients and
patients with advanced liver disease.
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