Second- and Third-Line Salvage Chemotherapy Followed by Allogeneic Stem Cell Transplantation Leads to High Survival...

Refractory acute myeloblastic leukemia (AML) is poorly studied. In this study, we characterized primary refractory AML and investigated treatment and outcome in a population-based setting. Based on all AML patients receiving intensive induction therapy at 12 Swedish hospitals from 2011 to 2018 (N = 1221), we identified 306 patients that failed to achieve composite complete remission (CRc) after first-line therapy. Two-hundred-sixteen (71%) of these patients received salvage treatment with intensive chemotherapy (ICT), of which 126 (58%) achieved CRc and 85 (39%) underwent allogeneic stem cell transplantation (HSCT). One- and 3-year overall survival (OS) in patients receiving salvage ICT were 56.8% and 28.9%, respectively. Secondary AML and adverse ELN risk were associated with worse OS after salvage ICT, while fludarabine-based FAIDA versus amsacrine-based ACE salvage and HSCT were associated with better OS. Three-year OS after first or second salvage chemotherapy, followed by HSCT were 55% and 71%, respectively. Refractory patients responding to salvage ICT showed only a nonsignificant trend toward inferior OS compared to patients in CRc after the first cycle. In conclusion, refractory AML patients eligible for further intensive therapy have a reasonable chance of obtaining remission and long-term survival when followed by HSCT. The results can serve as a basis for evaluation of new treatments in refractory AML.