OUTCOME OF PATIENTS WITH HIGH RISK ACUTE MYELOID LEUKAEMIA RELAPSED AFTER RELATED AND UNRELATED STEM CELL TRANSPLATATION. SINGLE CENTER EXPERIENCE

ABSSUB-4173

Background: Disease relapse is the most common cause of treatment failure after stem cell transplantation (SCT) for advanced myeloid malignancies, and generally carries a poor prognosis with short median survival without active treatment.

Aims: We describe treatment and outcomes for patients (pts) who relapse following SCT and compare the outcome of the group of pts transplanted with related and unrelated donor.

Methods: In a retrospective single center study we analyzed 204 pts (73 pts after related and 131 pts after unrelated SCT) with high risk AML  transplanted  between the years 2000 and 2013. 24 pts (33%) relapsed after related SCT and 37 pts (28%) relapsed after unrelated SCT (p= 0.5288). Median of relaps was 3 months in the group of related SCT(1-28 months) and 8 months (1-52) in the group of unrelated SCT (p= 0.0031). Both groups were comparable according to age, disease status, prognostic factors and the type of conditioning (myeloblative vs. reduced intensity conditioning, p=0,3401). 33 pts (54%) received aggressive treatment for relapse (12/24 and 21/37, p=0,7929) including donor lymphocyte infusion alone (DLI) (9/24 and 6/37, p= 0.0740), chemotherapy alone (2/24 and 6/37, p= 0.4621), chemotherapy with DLI (0/24 and 7/37, p= 0.0358) and second transplantation (1/24 and 2/37, p= 1,0).

Results: 11 pts (18%) archieved complete response (CR) after treatment for relapse (10 pts after DLI with or without chemotherapy and 1 pt after second transplantation), 1 pts transplanted with related donor and 10 pts transplanted with unrelated donor, p=0.0380. 5 pts still alive (1 from group of related SCT and 4 from group of unrelated SCT) 4-99 months after SCT with median of overall suvival(OS) 5 months after related SCT and 11 month after unrelated SCT, the probability of 1 year OS 8% and 22% (p=0,0293). 50 pts died, most of them due to disease progression (47/50, 94%), 1 pts died due to GVHD after DLI, 1 pts due to respiratory failure and 1 pts due to suicide. We did not observe difference in the outcome among pts treated with DLI alone, chemotherapy alone and second transplantation, better outcome had group of pts relapsed after unrelated transplant treated with chemotherapy and subsequent DLI.

Summary/Conclusion: Salvage chemotherapy, cellular therapy or second transplantation for AML relapse after SCT is feasible with low treatment-related mortality, but optimal management of the therapy for AML relapsing after SCT still remains to be defined. Comparing the group of pts transplanted with related donor and pts transplanted with unrelated donor better outcome was found in the group of unrelated transplantation treated with chemotherapy and DLI for AML relapse.

Keywords: Relapsed acute myeloid leukemia, Related donor, Transplant

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