More patients in the necitumumab plus gemcitabine and cisplatin group had grade 3-4 hypomagnesaemia ( 47 [ 9 % ] of 538 patients in the necitumumab plus gemcitabine and cisplatin group vs six [ 1 % ] of 541 in the gemcitabine and cisplatin group ) and grade 3 rash ( 20 [ 4 % ] vs one [ < 1 % ] ) .