Consistent
SVR Rates across All Weight Categories in the Canadian POWeR Program
The
purpose of the Canadian POWeR Program (PegIntron Prospective Optimal Weight-based
Dosing Response) was to determine the impact of hepatitis C virus (HCV) genotype,
body weight, and fibrosis stage at baseline on sustained virological response
(SVR) rates in treatment-naive chronic HCV patients who were treated with pegylated
interferon alfa-2b (PegIntron) plus weight-based ribavirin in a "real
life" community setting in Canada.
The
POWeR Program is a community-based, open-label trial conducted at 160 academic
and community clinics across Canada. All patients were treatment-naive and received
PegIntron 1.5 mcg/kg/week plus weight-based ribavirin (800-1200 mg/day). Genotype
2/3 patients were treated for 24 weeks, while genotype
1 patients were treated for 48 weeks.
SVR
was defined as undetectable HCV RNA (< 50 IU/mL) at 24 weeks post-treatment.
SVR rates were analyzed by body weight, baseline fibrosis stage, and genotype.
Results
2194 patients were enrolled in the POWeR Program.
This interim analysis was based on all patients with SVR data as of May 2006 (n=1476),
regardless of whether they received a full duration of therapy or discontinued
because of adverse events or lack of response.
Most patients (57%) had genotype 1 HCV, while the remainder had genotype 2 (17%),
3 (23%), other (genotypes 4, 5, or 6; 2%), or genotype not available (1%).
Genotype distribution was similar across all weight categories.
SVR rates ranged from 59% to 66% (see table).
Body weight had no effect on SVR.
There was a trend toward lower SVR rates in patients with advanced (stage F3-F4)
fibrosis.
SVR rates for patients with genotype 1, 2, and 3 were 49%, 86%, and 79%, respectively.
The overall
relapse rate, defined as patients who achieved an end-of-treatment response but
failed to achieve SVR, was 11.2%.
These
findings led the study authors to the following conclusions:
"This Canadian 'all inclusive' community-based program mirrors clinical trial
results in that treatment-naive patients treated with PegIntron plus weight-based
ribavirin have excellent genotype-specific SVR rates consistent with published
data."
"As others have shown, we observed a trend toward lower SVR rates in those
with more advanced fibrosis. Overall SVR rates were consistent (59%-66%) and independent
of patient baseline body weight."
"Thus this preliminary analysis of Canadian 'community based' treatment-naive
patients shows excellent SVR rates, low relapse rates, and strong evidence that
patient weight does not influence SVR rates in patients receiving this treatment
regimen."
TABLE
Weight, kg (n = 1476)
<50
50-<64
64-<75
75-<85
>85
SVR
62%
65%
61%
59%
66%
Fibrosis Stage (n = 815)
F0-F1
F2
F3
F4
SVR
74%
64%
41%
38%
Genotype
1
2
3
SVR (n/N)
49% (413/841)
86% (214/250)
79% (263/335)
London Health
Sciences Center, London, ON, Canada; Liver Study Unit, Mount Sinai Hospital, Toronto,
ON, Canada; University of Western Ontario, London, ON, Canada; Ottawa Hospital,
Ottawa, ON, Canada; Ontario Addiction Treatment Centres, Richmond Hill, ON, Canada;
Hamilton Health Sciences General Site, Hamilton, ON, Canada; Centre SIDA Amitié
des Laurentides, St. Jérôme, QC, Canada; Royal Alexandra Hospital,
Edmonton, AB, Canada; University of Alberta, Edmonton, AB, Canada; University
of British Columbia, Vancouver, BC, Canada; Schering Canada, Pointe Clare, QC,
Canada.
11/07/06
Reference P
Marotta, S V Feinman, C Ghent, and others. An Interim Analysis of the Canadian
POWeR Program (Peginterferon alfa-2b Prospective Optimal Weight-Based Dosing Response):
Consistent SVR Rates across All Weight Categories. 57th AASLD. October 27-31,
2006. Boston, MA. Abstract 358.
2194 patients were enrolled in the POWeR Program. 
