IDH2 (AG 221) Inhibitor in Patients With IDH2 Mutated Myelodysplastic Syndrome

INCLUSION CRITERIA: Patients must meet all of the following criteria to participate in the study: 1. Myelodysplastic syndrome according to World Health Organization (WHO) classification including non-proliferative AML up to 29% of Bone marrow (BM) blast 2. Age ≥ 18 years 3. Belonging to one of the following categories: 1. higher risk MDS (IPSS int-2, high) without response to azacitidine (Complete response (CR),Partial Response (PR), stable disease with HI) after at least 6 cycles , or relapsing after a response but without overt progression (defined by at least doubling of marrow blasts, compared to pre azacitidine bone marrow, or AML progression beyond 30% blasts) 2. Untreated higher risk MDS (IPSS int-2, high) without life threatening cytopenia including absolute neutrophil count (ANC) \<500/mm3 or any recent severe infections and/or platelets below 30,000/mm3 and any bleeding symptom 3. Lower risk MDS with resistance or loss of response to a previous treatment with epoetin alpha/ beta (≥60000 U/w) or Darbopoetin (≥250 ug/w) given for at least 12 weeks and red blood cell (RBC) transfusion requirement at least 2 U/8 weeks in the previous 16 weeks. 4. Presence of IDH2 mutation in either blood or marrow prior to start of therapy 5. Normal renal function, defined by creatinine less than 1.5 times the upper limit of normal, creatinine clearance (Modification of diet in renal disease) (MDRD) ≥ 50 mL/min. 6. Normal liver function, defined by total bilirubin and transaminases less than 1.5 times the upper limit of normal. 7. Adequate cardiac ejection fraction (\>40%) 8. Patient is not known to be refractory to platelet transfusions.Written informed consent. 9. Patient must understand and voluntarily sign consent form. 10. Patient must be able to adhere to the visit schedule as outlined in the study and follow protocol requirements. 11. Eastern Cooperative Oncology Group (ECOG) performance status 0-2 at the time of screening. 12. Female subjects of child-bearing potential must agree to undergo medically supervised pregnancy test prior to starting study drug. The first pregnancy test will be performed at screening (within 7 days prior to first study drug administration), and on the day of the first study drug administration and confirmed negative prior to dosing and Day 1 before dosing all subsequent cycles. 13. Female subjects with reproductive potential must have a negative serum pregnancy test within 7 days prior to the start of therapy. Subjects with reproductive potential are defined as sexually mature women who have not undergone a hysterectomy, bilateral oophorectomy or tubal occlusion or who have not been naturally postmenopausal (i.e., who have not menstruated at all) for at least 24 consecutive months (i.e., has had menses at any time in the preceding 24 consecutive months). Females of reproductive potential as well as fertile men and their partners who are female of reproductive potential must agree to abstain from sexual intercourse or to use two highly effective forms of contraception from the time of giving informed consent, during the study and for 120 days (females and males) following the last dose of AG-221. A highly effective form of contraception is defined as hormonal oral contraceptives, injectables, patches, intrauterine devices. Male patients must : Agree the need for the use of a condom if engaged in sexual activity with a woman of childbearing potential during the entire period of treatment, even if disruption of treatment and during 3 months after end of treatment. Agree to learn about the procedures for preservation of sperm before starting treatment EXCLUSION CRITERIA A patient meeting any of the following criteria is not eligible to participate in the study: 1. Severe infection or any other uncontrolled severe condition. 2. Significant cardiac disease - New York Heart Association (NYHA) Class III or IV or having suffered a myocardial infarction in the last 6 months. 3. Less than 14 days since prior treatment with growth factors (EPO, G-CSF). 4. Use of investigational agents within 30 days or any anticancer therapy within 2 weeks before the study entry with the exception of hydroxyurea. The patient must have recovered from all acute toxicity from any previous therapy. 5. Subject has a heart-rate corrected QT interval using Fridericia's method (QTcF) ≥ 470 msec or any other factor that increases the risk of QT prolongation or arrhythmic events (e.g., heart failure, hypokalemia, family history of long QT interval syndrome). Subjects with prolonged QTcF interval in the setting of bundle branch block may participate in the study. 6. Active cancer or cancer during the year prior to trial entry other than basal cell carcinoma, or carcinoma in situ of the cervix or breast. 7. Patient already enrolled in another therapeutic trial of an investigational drug. 8. Known HIV infection or active hepatitis B or C. 9. Women who are or could become pregnant or who are currently breastfeeding. 10. Any medical or psychiatric contraindication that would prevent the patient from understanding and signing the informed consent form. 11. Patient eligible for allogeneic stem cell transplantation. 12. Known allergies to AG-221 or any of its excipients. 13. No affiliation to a health insurance system.