A comparison of patients with acute myeloid leukemia and high-risk myelodysplastic syndrome treated on versus off study.

Patients with newly diagnosed (ND) and relapsed/refractory (RR) acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS, ≥10% blasts) often receive intensive chemotherapy at diagnosis and relapse. We retrospectively identified 365 patients and categorized the reasons for receiving treatment off study (medical, logistical, or unclear). The pretreatment characteristics of the on and off study groups were similar. Rates of the complete remission (CR) without measurable residual disease were significantly higher for ND patients treated on versus off study (61% versus 35%), but CR rates and survival were low for all RR patients regardless of study assignment. The subset of ND patients treated off study for medical reasons had significantly decreased overall survival and relapse-free survival. Standard, stringent study eligibility criteria may delineate a population of ND, but not RR, patients with improved outcomes with intensive induction chemotherapy.