Background:  Hepatitis C virus (HCV) is more difficult to treat in HIV-co-infected patients than in mono-infected patients. Sustained virological response (undetectable HCV RNA 24 weeks post-treatment) rates for HCV/HIV-co-infected patients treated with 180 µg/week pegylated interferon-α-2a (40 Kd) and 800 mg/day ribavirin for 48 weeks in the APRICOT study were 29% and 62% for genotype G1 and G2/3, respectively. There is therefore a need to identify patients with higher chances of sustained virological response in this population. We evaluated the predictive values for sustained virological response of both week 4 and week 12 on-treatment virological responses in HCV/HIV-co-infected patients, a treatment optimization strategy that has been successfully employed in mono-infected patients.
Methods:  This retrospective analysis included 271 patients with HCV G1 or G2/3 randomized to 180 µg/week peg-interferon-α-2a (40 Kd) and 800 mg/day ribavirin for 48 weeks in the APRICOT study. On-treatment responses were defined as rapid virological response (undetectable [<50 IU/mL] HCV RNA at week 4), complete early virological response (non-rapid virological response but undetectable HCV RNA at week 12) or partial early virological response (non-rapid virological response and non-complete early virological response but ≥2 log reduction in HCV RNA from baseline). The prediction of sustained virological response based on week 4 and week 12 responses was assessed.
Results:  Sustained virological response rates were high in HCV/HIV-co-infected patients who achieved an rapid virological response (G1, 81.8% [18 of 22]; G2/3, 94.3% [33 of 35]). The categorization of week 12 responses into complete and partial early virological response allowed patients who achieved high sustained virological response rates (G1, 63.2% [24 of 38]; G2/3 69.7% [23 of 33] in patients with a complete early virological response) to be distinguished from those with low sustained virological response rates (G1, 17.4% [8 of 46]; G2/3 18.2% [2 of 11] in patients with a partial early virological response).
Conclusions:  The predictive value of week 4 and week 12 responses for sustained virological response in co-infected patients is similar to that in mono-infected patients. While rapid virological response is the strongest predictor of sustained virological response, those co-infected patients with a complete early virological response also achieve high sustained virological response rates. Week 4 and 12 responses can be used to guide treatment decisions in HCV/HIV-co-infected patients. Prospective studies are needed to show whether these predictive values can be used for individualization strategies, such as shorter or longer treatment duration.