During study 3004, the incidence of AEs leading to treatment discontinuation was 28% for neratinib vs 5% for placebo. For diarrhoea, the discontinuations rates were 17% for neratinib vs 0.2% for placebo. Therefore, diarrhoea is the main cause of the marked difference in treatment discontinuation for neratinib compared to placebo. In routine clinical practice, there may be an even greater rate of treatment discontinuations due to diarrhoea, leading to a reduction in benefit.