inefficiency

Azacytidine (AZA) is the current standard of care for frontline patient treated with high-risk MDS and is clinically active in all type of MDS, however, 50% of the patients will never respond. Vorinostat is an orally available HDAC inhibitor with clinical activity in MDS and proven in vitro synergy with AZA. Patient treated upfront with a combination of this agents have shown more responses based on phase I/II data. In the present study, we will use the combination of these two drugs to try to create a synergetic effect and generate a response for patients who experienced treatment failure after AZA.

All eligible patients will be treated with Azacitidine and oral vorinostat for 6 cycles of 28 days. Study Design

Patients who meet eligibility criteria will be administered vorinostat orally at 300mg two times daily for 7 days as outlined in table 1.1. AZA will be administered SC at 75 mg/m2/day x 7 consecutive days or at maximum tolerated dose if a dose reduction of AZA was needed before entering the trial with a minimum dose of 50mg/m2/d for 7 consecutive days.

Each cycle will last 28 days with AZA starting on day 1 of each cycle and vorinostat starting on day 3.

Patients will receive 6 cycles unless progression is documented. Patients with a complete remission (CR), partial remission (PR), or hematological improvement (HI), will be treated until progression.

Inclusion Criteria:

• Myelodysplastic syndrome (WHO and FAB classified) including: RA, RARS, RCMD, RCMD-RS RAEB , RAEB-t and CMML with WBC < 13000/mm3)
• IPSS score 1.5 or higher (IPSS intermediate-2 and high risk categories) at the beginning of azacitidine,
• Absence of response (CR, PR, marrow CR or HI according to IWG 2006) after a minimum of 6 cycles of azacitidine single agent at 75 mg/m²/d for 7 days per cycle. Patients with a previous dose reduction of AZA may be eligible if the maximum tolerated dose was equal to or above 350mg/m2/cycle (i.e. 50 mg/m²/d for 7 days or 75mg/m2/d for 5 days).
• Age more or egal to 18 years
• ECOG performance status ≤ 2 (cf. appendix 2);
• Patient must have adequate organ function as indicated by the following laboratory values

Renal Serum creatinine or calculated creatinine clearancea < 2 mg/dl OR ≥ 60 mL/min for patients with creatinine levels > 1.5 X institutional ULN Hepatic

Serum total bilirubin ≤ 2.5 X ULN OR direct bilirubin ≤ ULN for patients with total bilirubin levels ≥ 2 mg/dL.

AST (SGOT) and ALT (SGPT) ≤ 2.5 times ULN Alkaline Phosphatase ≤ 5 X ULN If > 2.5 X ULN, then liver fraction should be ≤ 2.5 X ULN a Creatinine clearance should be calculated per institutional standard.

• Patient is known to not be refractory to platelet transfusions.
• Patient ineligible for allogeneic hematopoietic stem cell transplantation at the time of inclusion in the study
• Adherence to the study visit schedule;
• Women of childbearing potential must:

Agree to use effective contraception without interruption throughout the study and for a further 3 months after the end of treatment;

- Men must: Agree to not conceive during the treatment and to use effective contraception during the treatment period (including periods of dose reduction or temporary suspension) and for a further 3 months after the end of treatment if their partner is of childbearing potential.

Agree to learn about the procedures for preservation of sperm.

Exclusion Criteria:

• Patient had prior treatment with an HDAC inhibitor (e.g., depsipeptide or NSC-630176, MS 275, LAQ-824, PXD-101, LBH589, MGCD0103, CRA024781, etc). Patients who have received compounds with HDAC inhibitor-like activity, such as valproic acid, as anti-tumor therapy should not enroll in this study. Patients who have received such compounds for other indications, e.g. valproic acid for epilepsy, may enroll after a 30-day washout period.
• Severe infection or any other uncontrolled severe condition.
• Last dose of AZA was given more than 3 months before entering the trial.
• Patient already enrolled in another therapeutic trial of an investigational drug
• HIV infection or active hepatitis B or C.
• Patient has a known allergy or hypersensitivity to any component of vorinostat or azacitidine.
• 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.
• Less than 30 days since prior treatment with growth factors (EPO, G-CSF) or non-cytotoxic agents (including low-dose oral chemotherapy); in the event of prior treatment with cytotoxic or demethylating agents, an interval of 3 months is required;
• Patient is on any systemic steroids that have not been stabilized to the equivalent of ≤ 10 mg/day prednisone during the 4 weeks prior to the start of the study drugs.
• Patients with clinical evidence of CNS leukemia.
• Patient has a history of GI surgery or other procedures that might interfere with the absorption or swallowing of the study drugs.
• Women who are or could become pregnant, or who are currently breastfeeding
• Patient eligible for allotransplantation at the time of inclusion.