Outcomes of adult patients with type 1 primary refractory acute myeloid leukemia: a single center experience

Adult patients with newly diagnosed de novo acute myeloid leukemia (AML), who had less than a 50% reduction in blast numbers and with > 15% residual blasts after first cycle of induction chemotherapy, defined as type 1 primary refractory (REF1), have grave prognosis. We retrospectively analyzed the data of 58 patients with REF1 who received salvage treatments with curative intension to evaluate the impact of salvage regimens with regard to response and overall survival (OS). Seventeen patients received intermediate- or high-dose cytarabine (ID/HD Ara-C) based intensive salvage chemotherapy, 36 patients received G-CSF primed less intensive chemotherapy and 5 patients received novel targeted drugs based low intensive therapy. The CR/CRi and MLFS rate was 6/17 and 2/17, 14/36 and 3/36, 3/5 and 0/5, respectively. The median OS for the whole cohort was 20.3 months. Median OS was comparable between the 3 arms. Overall, 42 patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), 14 patients in the intensive arm, 24 patients in the less intensive arm and 4 patients in the low intensive arm. Median survival for allo-HSCT patients was significantly longer than for non-allo-HSCT patients (38.8 months vs. 2.1 months, p < 0.001). In multivariate analysis, achievement of CR/CRi after the salvage regimen were predictive of OS. We conclude that no significant difference in outcome among traditional salvage regimens in patients with REF1. G-CSF primed less intensive chemotherapy could serve as an alternative of ID/HD Ara-C based intensive chemotherapy and allo-HSCT is indispensable for long-term survival.