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PREDICTORS OF RELAPSE IN THE CANADIAN POWER (PEGETRON PROSPECTIVE OPTIMAL WEIGHT-BASED DOSING RESPONSE) PROGRAM
J Robert, F Wong, S Feinman, B Romanowski, M Elkashab, R Woolstencroft, P Marotta
Centre Sida Amitié des Laurentides; University of Toronto; Mount Sinai Hospital; University of Alberta; Toronto Liver Centre; Schering-Plough Canada; London Health Sciences Centre
AIM: This subanalysis of the POWeR program reports on predictors of relapse in treatment-naïve patients with chronic hepatitis C who were treated with PEG-IFN alpha-2b and weight-based ribavirin (RBV) in “real-life” clinical settings.
METHODS: POWeR was a Canadian open-label observational trial conducted between 2002 and 2007. Patients received PEG-IFN 2b (1.5µg/kg/wk) + weight-based RBV (800-1200mg/d) as described previously. End of treatment (EOT) response was defined as undetectable HCV RNA at completion of therapy; sustained virologic response (SVR) was defined as undetectable HCV RNA 24 weeks post-treatment. Relapse rates [((EOT-SVR)/EOT) ×100] were analyzed by genotype, baseline viral load, weight and fibrosis score.
RESULTS: 1977 patients initiated treatment. Patients (N=1800; 946 with liver biopsy specimens) in this analysis included those who discontinued because of side effects or lack of response. Patients were excluded if they had undetectable HCV RNA at EOT but no 6-month follow up, had no treatment data, or had HIV/HCV co-infection. EOT responses were 50%, 86% and 77% for Genotype (G)1, G2 and G3, respectively; corresponding SVR rates were 42%, 79% and 72%. The overall relapse rate was low (12%) but was significantly higher in G1 patients (17%) than in G2 and G3 patients (7.6% and 6.4%, respectively) (G1 vs G2 or G3, P<0.001). No notable differences in relapse were observed by viral load for any genotype, including 17% relapse in each of G1 LVL and HVL patients. Relapse rates were similar irrespective of fibrosis score in G2 and G3 patients (p=ns) but significantly higher in G1 patients with advanced fibrosis/cirrhosis versus minimal fibrosis (30% vs 8%; P<0.01).
CONCLUSIONS: Baseline viral load and weight were not independently associated with increased relapse, for any genotype, in patients treated with PEG-IFN alpha-2b plus weight-based RBV. Advanced fibrosis significantly affected relapse rates in patients infected with G1, but not G2 or G3. Dose optimization or extended duration of therapy should be investigated in this patient population.
Supported by Schering-Plough