“…Several new agents such as topotecan (Seibel et al, 2007), irinotecan (Crews et al, 2004;Bagatell et al, 2014), imatinib mesylate (Bond et al, 2008), gefitinib (Brennan et al, 2014), trabectedin (Chuk et al, 2012), pirarubicin (Qi et al, 2012), ifosfamide (Choeyprasert et al, 2014;Li et al, 2014) and gemcitabine (Qi et al, 2012) have been investigated in pediatric and adult patients, but the response rate is low and survival time is short. As a result, we undertook this retrospective study to investigate the activity of continuous-infusion ifosfamide and doxorubicin combination as secondline therapy for patients with relapsing and refractory osteosarcoma.…”