It is not known whether the probability of achieving sustained virological response (SVR) can be determined on the basis of the magnitude of HCV viral decline over the first 4 weeks of Peg-IFN/RBV treatment of HIV/HCV co-infected patients who fail to achieve a rapid virological response (RVR).

HIV patients co-infected with HCV genotype 1 naïve to Peg-IFN/RBV treatment were included. HCV viral decline from baseline to week 4 was graded. The positive predictive value (PPV) for SVR was evaluated according to the magnitude of HCV viral decline at week 4.

One hundred and fifty patients were included. Thirty-four (22.6%) patients achieved RVR, 33 of these (PPV [CI 95%]; 97.05% [86.34–99.85]) achieved SVR. In those patients who did not achieve RVR, the probability to achieving SVR was graded according to the magnitude of viral decline at week 4 (>2 log₁₀ [55.5%], >2.5 log₁₀ [73.3%] and >3 log₁₀ [75%]). The combination of undetectable and magnitude of decline (>2.5 log₁₀) had a PPV for SVR of 89.8% (CI 95%; 0.794–0.964).

The combination of undetectable HCV viral load and magnitude of decline at week 4 has a high PPV for SVR and identified a higher number of potential Peg-IFN/RBV responders.