Platelet
Count Is a Strong Predictor of Sustained Response to Pegylated Interferon/ribavirin
in Prior Non-Responders (EPIC 3) By
Liz Highleyman  | Thrombocytes,
or platelets, are the smallest cellular component of blood. |
|
At
last month's meeting of the European Association
for the Study of the Liver (EASL) in Milan, investigators with the EPIC 3
trial reported that HCV
genotype was the strongest predictor of sustained response to re-treatment
of prior non-responders with pegylated
interferon plus ribavirin. Extent
of liver disease, indicated by degree of fibrosis,
was also a predictive factor. The researchers presented further information on
the association between treatment response and liver disease at the Digestive
Disease Week (DDW) 2008 conference this week in San Diego.
EPIC 3 trial,
sponsored by Schering-Plough, evaluated the safety and efficacy of re-treatment
of previous non-responders using 1.5
mcg/kg/week pegylated interferon alfa-2b (PegIntron) plus 800-1400 mg/day weight-based
ribavirin for 48 weeks. Participants included both compete prior non-responders
and relapsers who had previously been treated with either conventional
or pegylated interferon plus ribavirin.
In the present analysis -
which included a subset of 1354 patients -- the researchers looked at the association
between sustained virological response and platelet count. Platelets (thrombocytes)
are a type of blood cell responsible for blood clotting, and low platelet counts
(thrombocytopenia) correlate with advanced fibrosis. All participants had pre-treatment
biopsies scored by a single reviewer and had significant fibrosis (METAVIR stages
F2-F4) at baseline. Results
•
The
overall SVR rate was 22%.
•
Among
patients with undetectable HCV RNA at week 12 of treatment, 56% achieved SVR.
•
The
likelihood of SVR decreased with increasing fibrosis stage, as shown in the table
below.
•
SVR
rates also decreased with declining baseline platelet counts (P < 0.0001).
•
In
logistic regression analysis considering HCV genotype, baseline viral load, previous
response (complete non-response or relapse), type of previous therapy, baseline
platelet count, and fibrosis, both platelet count (P = 0.0114) and degree of fibrosis
(P = 0.0313) were independent predictors of poor response.
•
Odds
ratios were 1.88 for platelet count >200,000 vs < 150,000 cells/mm3
and 1.73 for F2 vs F4 fibrosis.
•
Using
a regression-tree analysis, a platelet count of 149,000 cells/mm3 was the best
differentiator for sustained response, with SVR rates of 16% for patients with
a platelet count < 150,000 cells/mm3 and 26% for those with > 150,000
cells/mm3.
•
Participants
with platelet counts above and below 150,000 copies/mm3 had a similar distribution
of genotypes and similar adherence to therapy.
Conclusion "Both
advanced fibrosis and low platelet counts are predictors of poorer response to
re-treatment in previous [interferon/ribavirin] treatment failures," the
study investigators concluded. They
added that, "Thrombocytopenia < 150,000 cells/mm3 may be a simple, robust,
non-invasive predictor of SVR with PegIntron/ribavirin therapy in previous non-responders.
5/20/08
Reference
T
Poynard, E Schiff, R Terg, and others. Results from the EPIC 3 Program: Platelet
counts are strong predictors of sustained viral response (SVR) in the re-treatment
of previous interferon/ribavirin non-responders (NR). Digestive Disease Week (DDW)
2008. San Diego, CA. May 17-22, 2008. Abstract S1000.
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