• Preplanned subgroup analysis indicated improved OS benefit with
increasing HER2 expression by IHC
• Exploratory analysis of IHC 2+/FISH+ and IHC 3+ cohort demonstrated a
4-mo increase in OS with trastuzumab
• HR: 0.65 (95% CI: 0.51-0.83)
Bang YJ, et al. Lancet. 2010;376:687-697.