The most common grade 3-4 adverse events were peripheral neuropathy ( in 18 [ 24 % ] of 76 patients who received chemotherapy plus cetuximab vs ten [ 15 % ] of 68 who received chemotherapy alone ) , neutropenia ( 17 [ 22 % ] vs 11 [ 16 % ] ) , and increased aminotransferase concentrations ( 17 [ 22 % ] vs ten [ 15 % ] ) .