In the open-label phase IIa segment ( N = 51 ) , the majority of the 64 AEs reported in 31 ( 75.6 % ) balugrastim-treated patients were grade 1 ( 59.4 % ) , with 39.1 % grade 2 , 1.6 % grade 3 ( one AE of vomiting ) , and none grade 4 .