IGF1R and Ewing sarcoma: However, as more patients with Ewing sarcoma were enrolled onto clinical trials, it became clear that objective response rates for anti-IGF1R MABs were generally in the 10 % to 15 % range for Ewing sarcoma and that most responses were not prolonged (Juergens et al., 2011; Malempati et al., 2012; Pappo et al., 2011; Schoffski et al., 2013; Tap et al., 2012).