We fully agree with Dr. Yu and co-workers that maintaining the initial doses of ribavirin during the treatment play a decisive role in attaining sustained virological response (SVR). According to Davis et al., 2 the impact of dose reduction on SVR rates appeared to be greatest in patients who had to reduce the assigned ribavirin dose within the initial 12 weeks of treatment. For this reason, we tried to maintain the starting ribavirin doses in almost all our patients during the first 4 weeks of treatment and allowed them to use epoetin rather than reducing ribavirin dosage. As a consequence, our study is not completely comparable to those quoted by Dr. Yu.
Only 22 (4.5%) of our patients experienced ribavirin dose reduction during the first 12 weeks overall. In four cases, this dose reduction was required during the first 4 weeks. Therefore, of 185 patients with RVR, four (2.1%) have had dose reduction of ribavirin. By contrast, of 310 patients without RVR, very few patients (19 [6.0%]) have had ribavirin dose reduction. In our experience, the ribavirin exposure appears to be one of several factors influencing the likelihood of achieving RVR, at least in patients infected with HCV genotype 1. It has been recently reported that neither early virologic response nor SVR are adversely affected by ribavirin dose reduction unless it is greater than 60% of the cumulative dose. 3,4 Similar findings are reported in patients infected with genotype 2 and 3. 5 On the basis of these data, we suppose that a starting weight-based dose of ribavirin rather than a reduction of ribavirin dosage during treatment might have a major impact as a modifiable favorable predictor of SVR in patients with chronic HCV genotype 1 infection.