5-Azacytidine Before or After Stem Cell Transplantation in Acute Myeloid Leukaemia (AML) and Myelodysplastic Syndromes (MDS)
Authors: Garrido Ana , Ortín Miguel , Martino Rodrigo , Nomdedeu Josep , Aventin Ana , Hoyos Montserrat , Brunet Salut , Sierra Jordi 
Published: October 2019

Abstract
Abstract 4267
The acceptable toxic profile of 5-aza-citidine (5-aza) allows its use in fragile or elderly patients in whom intensive chemotherapy should be avoided. Whether it is possible to take advantage of this low toxicity in patients awaiting for donor search and/or stem cell transplant (SCT) and in those experiencing leukemia recurrences after the procedure remains unknown. We analysed the clinical results of using 5-aza in these two settings to define the feasibility, safety and results of this approach.

Patients and methods:
From 2007 to 2011, 15 patients (11 males, 4 females) received 5-aza as last treatment prior to an allogeneic SCT (n=13) or as rescue after an early post-transplant relapse (n=2) at our centre. Diagnosis was MDS in 3 cases (median age 62; range 58–63) and AML in 12 cases (median age 58; range 37–67). Patients with MDS received a median of 6 courses of 5-aza (range 3–8) as the only treatment from diagnosis, except for one patient who had received panobinostat prior to 5-aza. Amongst patients with AML, 12 patients received 5-aza either as treatment for AML (2/12) or after remission (8/12) because of the high relapse risk while awaiting for a suitable donor to be found. Two patients with AML received 5-aza as treatment for early post-SCT relapse. AML patients treated with 5-aza before SCT received a median of 5 courses (range 1–19), whilst patients receiving treatment for relapse received 1 and 3 courses, respectively. Ten patients received a nonmyeloablative conditioning regimen, 1 received a conventional conditioning regimen, 2 patients are still in the process of donor search and the other 2 patients received 5-aza after an autologous stem cell transplantation relapse.

RESULTS:
All MDS patients engrafted and are in complete remission (CR) after a median of 696 days of follow-up (range 377–1227). One of those patients died because of aGvHD. Nine of 12 AML patients receiving 5-aza prior to SCT are alive after a median 373 days follow-up (133–995). One patient showing refractoriness to 3 different lines of treatment died from disease progression after 211 days. All patients receiving 5-aza as treatment for early relapse are dead, 41 and 401 days after starting treatment. Most interestingly, AML patients receiving 5-aza as maintenance of an already-achieved CR while awaiting transplantation did not experience disease progression despite the median time they remained on this treatment was prolonged (9 months). Graft-versus-host disease ≥ grade II was seen in 3 patients. No graft failures were seen and all patients who received an allogeneic stem cell transplantation remain in complete response.

CONCLUSION:
The use of 5-aza for maintaining or achieving a response in patients with AML who are awaiting SCT is a safe procedure and adds flexibility to schedule the treatment without the need to administer potentially toxic therapy. The use of 5-aza before transplant did not appear to interfere either with engraftment, incidence of GvHD or short-term relapse after transplant.

Disclosures:
No relevant conflicts of interest to declare.