The most common treatment-related grade 3 or 4 adverse events in the afatinib group were rash or acne ( 35 [ 146 % ] of 239 patients ) , diarrhoea ( 13 [ 54 % ] ) , and stomatitis or mucositis ( 13 [ 54 % ] ) , compared with neutropenia ( 30 [ 265 % ] of 113 patients ) , vomiting ( 22 [ 195 % ] ) , and leucopenia ( 17 [ 150 % ] ) in the gemcitabine and cisplatin group .