Nature Reviews Drug Discovery 6, 991–1000 (December 2007) | doi:10.1038/nrd2411
On page 996, in the first paragraph of the right-hand column, which discusses studies with boceprevir, pegIFN-
2a was stated as the pegylated interferon that patients had previously failed in order to be considered non-responders. This is not accurate since they could have failed pegIFN-2a or pegIFN-2b. In addition, pegIFN-2a was stated as the pegylated interferon being used in combination with boceprevir in Phase I and Phase II studies. However, the pegylated interferon used is pegIFN-2b.
The statements should read as follows:
A dose-ranging study of boceprevir (100–400 mg twice a day) in patients with HCV genotype 1 that had previously failed pegIFN-2 therapy indicates that this protease inhibitor has dose-related antiviral activity as monotherapy. A Phase Ib 14-day study of boceprevir (200 or 400 mg three times daily) administered in combination with pegIFN-2b (1.5 
g per kg weekly) demonstrated a dose–response relationship in non-responder patients with HCV genotype 1. Mean maximum log10 reductions in HCV RNA were 2.45 and 2.88 for 200 and 400 mg boceprevir plus pegIFN-2b, respectively49, and the combination of agents provided greater antiviral activity than either drug as monotherapy. Boceprevir 800 mg three times a day is currently being evaluated in combination with pegIFN-2b and ribavirin in a Phase II trial of non-responders. A further Phase II trial of boceprevir 800 mg three times a day in combination with pegIFN-2b and ribavirin has also been initiated in treatment-naive patients. Recent preliminary results from this so-called SPRINT (Serine Protease Inhibitor Therapy) study are comparable to the two telapravir Phase II studies in treatment naive patients113–115.
