Introduction Studies have shown that attaining a rapid viral response (RVR) (PCR negative after 4 weeks of interferon and ribavirin therapy) is emerging as a robust predictor of sustained viral response (SVR) to treatment. We started routinely measuring HCV PCR after 4 weeks of treatment in April 2007. The aim of this study was to evaluate the frequency and outcomes associated with RVR in clinical practice.
Methods A prospective study was carried out on all individuals who had received interferon and ribavirin therapy in our centre between April 2007 and November 2009.
Results A total of 164 individuals were included in the study. 111 (67.7%) were male. The age range was 19 to 77 with a mean of 43.8 years. 67 (40.8%) were genotype 1, 7 (4.2%) genotype 2, 88 (53.6%) genotype 3, and 2 (1.2%) genotype 4.
At end week 4, 80/164 (48.7%) had a RVR, of these 22% were genotype 1/4 and 67.7% were 2/3. Of the individuals who did not achieve a RVR, 49 (29.9%) had more than a 2-log drop in viral load, 28 (17%) had less than a 2-log drop and 7 (4.2%) stopped treatment before 4 weeks. 36 individuals are still in treatment. In 128 cases where treatment has ended 75% (96/128) completed treatment.
The following analysis focuses on the 96 individuals who are 6 months post treatment. Of the 39 had achieved an RVR (6 genotype 1/4. 33 genotype 2/3), three stopped treatment early (between 4 and 12 weeks) and 35 (97.2%) who subsequently completed treatment achieved a SVR. 21 (84%) who achieved more than a 2-log drop at 4 weeks and completed treatment had SVR and 3 (42.8%) who had less than a 2-log drop had SVR (Abstract 071).
Conclusion This study shows that 48.7% of individuals achieved a RVR. The frequency of RVR was significantly altered by genotype. This study confirms that the result of viral load at 4 weeks is very predictive of an SVR if individuals adhere to treatment, with 97.2% of individuals with RVR who completed treatment achieving a SVR. The numbers in this study are small however the results can be used to motivate individuals with RVR or more than a 2 log drop in viral load at 4 weeks to complete their full course of treatment.