Women had higher incidences of grade III (54% versus 14%) and grade IV (31% versus 5%) anemia (P < 0.001) due to sex differences in baseline values rather than differences in on-treatment change (day 14 drop in Hb level of 2.14 g/dl for males versus 2.21 g/dl for females; P = 0.92) (Fig. 1c). Here, GSTM1 is linked to anemia (phenotype).