Plasma HCV-RNA decline in the first 48 h identifies hepatitis C virus mono-infected but not HCVHIV-coinfected patients with an undetectable HCV viral load at week 4 of peginterferon-alfa-2aribavirin therapy

During peginterferon-alfa-2aribavirin therapy, plasma hepatitis C virus (HCV)-RNA decreases with a rapid first phase and a slower second phase. We compared the viral load decrease and slope in the first 48 h in patients with a rapid viral response (RVR, i.e. HCV-RNA < 50 IUmL at week 4) with patients not achieving an RVR. From 23 HCV-infected (14 mono-infected and nine HCVHIV-coinfected) genotype 1 or 4 positive peginterferon-alfa-2aribavirin- treated patients, plasma HCV-RNA was determined at baseline, 48 h, weeks 1, 2, 4, 8, 12, 48 and 72. The HCV viral load decrease (0-48), the slope (λ₁) and the efficiency factor (ε) were determined in the first 48 h after the start of therapy. Five (36%) HCV mono-infected patients and three (33%) HIVHCV-coinfected patients achieved an RVR whereas six (43%) HCV mono-infected patients and five (56%) HIVHCV-coinfected patients reached a sustained viral response (SVR). In contrast to HIVHCV-coinfected patients, five HCV mono-infected patients with an RVR showed both a larger 0-48 and steeper ₁ (-1.77log₁₀ IUmL ± 0.66 and -2.04day ± 0.76) compared to nine non-RVR patients (-0.66log₁₀ IUmL ± 0.39; P = 0.019 and -0.76day ± 0.41; P = 0.019). When divided by SVR, a greater 0-48 and steeper λ₁ were also seen in both HCV mono-infected and HIVHCV-coinfected patients. Thus, in the first 48 h after the start of therapy, HCV mono-infected patients with an RVR have a larger viral load decrease, steeper viral slope and a higher efficiency factor as compared with non-RVR patients.