Successful re-treatment with azacitidine in a patient with low blast count AML transformed from MDS after suspension of this agent

which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Successful re-treatment with azacitidine in a patient with low blast count AML transformed from MDS after suspension of this agent TO THE EDITOR: The treatment approach to acute myeloid leukemia (AML) transformed from high-risk myelodys-plastic syndrome (MDS) after azacitidine failure is not standardized and the clinical results achievable in this setting are generally disappointing [1-3]. Similarly, poor outcomes have also been reported in the setting of AML transformation following azacitidine discontinuation due to reasons other than hematologic progression in MDS patients initially responding to hypomethylating therapy [4]. Little is known of azacitidine-responsive MDS patients who progressed to AML with 20–30% bone marrow (BM) blasts after suspension of this agent, nor of the possibility to re-induce hematological control after the resumption of hypomethylating therapy. Herein, we report the case of a 63-year-old woman diagnosed in April 2007 with refractory anemia with excess blasts subtype 2 (RAEB-2) who presented with trilinear symptomatic pancytopenia, a 15% BM blast infiltration, a normal karyotype, and a significant transfusion requirement of red blood cells (RBC) units. The International Prognostic Scoring System (IPSS) [5] score was 2, qualifying the patient's MDS as intermediate-2 risk. The World Health Organization (WHO)-adapted Prognostic Scoring System (WPSS) [6] score was 4 (high risk). The patient presented with cardiac, pulmonary, and gastrointestinal comorbidities indicating a MDS-Comorbidity Index (CI) score [7] as high as 3 (high risk). Therefore, the patient was qualified as unsuitable for AML intensive chemotherapy (IC). So that, in July 2007, she was started on azacitidine (75 mg/m 2 , schedule 5＋2＋2) with good compliance and without significant adverse effects. After 8 cycles (May 2008), a complete remission (CR) was documented. The patient then continued the same treatment (28 cycles) in CR with normal blood counts and without significant toxicity until March 2011, when febrile diverticulitis, an infected perianal fistula and, soon after, pneumonia were consecutively observed. Because of the normal neutrophil count, these clinical complications were considered to be related to the pre-existing comorbidities rather than associated with the azacitidine therapy. However, given the severity of the complications, requiring surgery and long term antibiotic therapy, azacitidine was stopped. A progressive pancytopenia was observed after the discontinuation of azacitidine to the point of disease progression to AML that was diagnosed 4 months later (July 2011). The BM was characterized by multilineage dysplasia …