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EXPOSURE TO RIBAVIRIN (RBV) PREDICTS EVR AND SVR IN PATIENTS WITH HCV GENOTYPE 1 INFECTION: ANALYSIS OF THE CANADIAN PEGASYS EXPANDED ACCESS PROGRAM (EAP)

VG Bain¹, SS Lee², K Peltekian³, E Yoshida⁴, M Deschênes⁵, M Sherman⁶, R Bailey⁷, H Witt-Sullivan⁸, R Balshaw⁹, M Krajden¹⁰; on behalf of the Canadian PEGASYS Study Group
¹University of Alberta, Edmonton; ²University of Calgary, Calgary, Alberta; ³Dalhousie University, Halifax, Nova Scotia; ⁴Vancouver Hospital Health Sciences Centre, Vancouver, British Columbia; ⁵Royal Victoria Hospital, Montreal, Quebec; ⁶University Health Network, Toronto, Ontario; ⁷Royal Alexandra Hospital, Edmonton, Alberta; ⁸Hamilton Health Sciences Corp, Hamilton, Ontario; ⁹Syreon Corp Vancouver, Vancouver; ¹⁰BC Centre for Disease Control, Vancouver, British Columbia

We examined the relationship between exposure to PEG-IFNalpha2a and RBV and the probability of EVR and SVR.
METHODS: All treatment-naïve G1 pts assigned to PEG-IFNalpha2a+RBV for 48wks and with known SVR status were included. In the initial phase all pts received RBV 800mg/d, and 1000/1200mg/d in later phases. RBV 1000/1200mg/d was defined as the optimal dose (100%). Dose adjustments for AEs/lab abs were included in a continuous measure of exposure (%). EVR = =>2-log drop in HCV-RNA at wk12. SVR = HCV-RNA <50 IU/mL at end of follow-up.
RESULTS: 720 pts were included (318 RBV 800; 402 RBV 1000/1200). At wk12 mean RBV exposure was 70% (RBV 800) and 97% (RBV 1000/1200) of optimal. To wk12 the mean dose of PEG-IFNalpha2a was 94% of the planned dose. Among pts assigned to RBV 800 and 1000/1200mg/d 73% and 80% had an EVR; and 47% and 61% had an SVR, respectively. Predictors of EVR included weight (p=0.025) and RBV exposure (p=0.0173). Predictors of SVR by multiple logistic regression were RBV exposure (p<0.0001), baseline HCV-RNA (p<0.0001), race (p<0.0001), fibrosis score (p=0.0075) and age (p=0.033). PEG-IFNalpha2a exposure was not associated with SVR, but showed a trend for the prediction of EVR (p=0.051).
CONCLUSION: Exposure to RBV, but not PEG-IFNalpha2a was significantly correlated with probability of EVR and SVR. Exposure to PEG-IFNalpha2a was near optimal, which limits our ability to address its impact on outcomes.
Funded by Roche Canada