In contrast only 5 of 13 patients (38%) with detectable HCV-RNA at day 29 achieved SVR when treated for 24 weeks of combination therapy as compared to 16 of 23 (70%) of matched controls treated for 48 weeks. Though this difference was not significant (P Ο 0.09, Fisher's exact test), it suggests that 48 weeks of treatment may be preferential in this group in accordance with the findings by Jensen et al.
In agreement with the findings by Jensen et al., we observed that patients with baseline HCV-RNA below the previously reported threshold of 600,000 IU/ml 3 were statistically more likely to have undetectable HCV-RNA at day 29 (63% versus 32%, P Ο 0.01) as well as had a trend toward greater likelihood of achieving SVR (89% versus 50%, P Ο 0.06). Indeed, 8 of 9 patients with a baseline viral load below 600,000 IU/ml achieved SVR. However, in our study, having a low baseline viral load appeared less clinically useful than undetectable HCV-RNA early during the course of therapy, and when adding these 2 predictors of SVR, fewer patients achieving SVR were identified as compared to undetectable HCV-RNA day 29 alone as demonstrated in Table 1. It is also worth noting in our study that among the 15 patients achieving SVR, only 8 had a baseline viral load below 600,000 IU/ml. Interestingly, in our study, baseline viral load was not predictive of SVR in the matched control patients treated for 48 weeks.
In conclusion, these findings support the results presented by Jensen et al. that 24 weeks of combination therapy is feasible in HCV genotype 1 infected patients provided that viremia is cleared early during therapy, and that early HCV-RNA clearance is significantly associated with low baseline viral load.