The most common grade 3-4 adverse events were diarrhoea ( 59 [ 12 % ] patients on dacomitinib vs no controls ) , acneiform rash ( 48 [ 10 % ] vs one [ < 1 % ] ) , oral mucositis ( 16 [ 3 % ] vs none ) , and fatigue ( 13 [ 3 % ] vs four [ 2 % ] ) .