Azacitidine in Relapsed and Refractory AML: Efficacy for Patients Relapsing As MDS Post AML

Azacitidine (Aza), inhibitor of DNA methyltransferases, plays an important role in epigenetic regulation of gene expression and tumorogenesis, and is active in myeloid neoplasia such as myelodysplasia (MDS) and de novo acute myeloid leukemia (AML). Efficacy of Aza for relapsed and refractory AML has not been so far reported.

We report in 2 french centers (Amiens, Rouen) retrospective study, the results of Aza for relapsed or refractory patients. All patients received Aza (75 mg/m2 per day over 7 days for 4 weeks cycles), until progression, and at least one cycle. Leukocyte blood count was < 1010⁹/l. The primary endpoint was overall response rate (ORR), according to IWG 2006: complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD), hematological improvement (HI). Secondary endpoints were duration of response and overall survival (OS).

41 patients (26 males and 15 females) with a median age of 59 years (range 28–78) were studied from August, 2007 and November, 2011 (Table): 15 had refractory and 26 relapsed AML. At relapse 11/26 had MDS, defined by blast count <20% and cytological morphology of MDS in bone marrow aspirate, and 15/26 AML.

Patients received in average 6 cycles (1–30): 4 (1–7) for refractory; 7 (1–30) for relapsed (11 (3–30) for MDS post AML; 3 (3–5) for relapsed AML).

Overall, the ORR was 34% (7 CR, 5 RP, and 9 HI). For patients with MDS post AML OR was 82% (7 CR, 2 RP, 7 HI), 13% (1 RP, 1 HI) for relapsed AML, and 13% (2 PR and 1HI) for refractory AML.

The average duration of response was 4 months (0–39) for the 41 patients: 14 months (0–39) for MDS post AML, 0.3 for relapsed AML, and 0.5 for refractory.

Overall survival from diagnosis was 29 months (6.9–87): 38.2 (12–57) for MDS post AML, 30.1 (6.9–87) for relapsed AML and 13.3 (6.9–35.5) for refractory (no significant differences).

Overall survival from initiation of Aza was 9.4 months (1.1–39.2): 22.6 (4.8–39.2) for MDS post relapsed and 3.9 (0.3–11.3) for relapsed AML and 6.2 (1.1–13.3) for refractory patients. The differences are not statically significant probably due to small effective of our study. Contrarily to the others 2 groups, 6 patients (55%) with MDS post AML are alive in CR at the latest report; moreover three of them underwent an allogeneic transplantation.

Aza seems to efficient for relapsed AML patient, especially for MDS post AML, but inappropriate for refractory patients.

No relevant conflicts of interest to declare.