Cetuximab plus cisplatin-radiation , versus cisplatin-radiation alone , resulted in more frequent interruptions in radiation therapy ( 26.9 % v. 15.1 % , respectively ) ; similar cisplatin delivery ( mean , 185.7 mg/m2 v. 191.1 mg/m2 , respectively ) ; and more grade 3 to 4 radiation mucositis ( 43.2 % v. 33.3 % , respectively ) , rash , fatigue , anorexia , and hypokalemia , but not more late toxicity .