The most common grade 3 or worse adverse events in both treatment groups were haematotoxicity ( 73 [ 25 % ] of 297 patients in the cetuximab group vs 62 [ 21 % ] of 295 patients in the bevacizumab group ) , skin reactions ( 77 [ 26 % ] vs six [ 2 % ] ) , and diarrhoea ( 34 [ 11 % ] vs 40 [ 14 % ] ) .