A PROSPECTIVE OBSERVATIONAL FOLLOW-UP STUDY OF PEGINTERFERON ALFA-2A PLUS RIBAVIRIN TREATMENT IN PATIENTS WITH CHRONIC HEPATITIS C GENOTYPE 1 AND WITH NORMAL ALT LEVELS: INTERMEDIATE EFFICACY ANALYSIS - Calleja, Jose L; Ruiz-Antoron, Belen; Garcia-Samaniego, Javier; Morillas, R; Moreno-Otero, Ricardo; Carlos Erdozain, Jose; Nogueras, F; Suarez, D; Banos, F; Grande-Santamaria, Lourdes; Sola, Ricard; Pons, Jose A; et al. (Hepatology, 2009)