The regimen’s success may testify to the utility of RBV in preventing resistance, or possibly, as some have speculated, to high intrahepatic concentrations
of ritonavir-boosted ABT-450, permitting suppression
of low-level resistant variants. The lower SVR rates in null responders, associated with substantial relapse rates, reflect an important emerging and unanticipated theme—the importance of host pathways, reflected by IFN responsiveness, in mediating viral eradication with IFN-free regimens.