The study is an open-label, 3+3 dose-escalation, phase I/II study.The duration of enrollment in the phase I study is 12 months.~Fourteen patients will be enrolled at the RD using the selected dosing in each cohort, for an enrollment period of 12 months.~Each patient may receive up to 8 courses, every 4 to 8 weeks in a D1-D5 schedule or every other day from D1 to D10.~Each patient will be followed for up to 24 months.~Primary endpoint of the phase I part:~To determine the maximal tolerated dose (MTD) and dose limiting toxicities (DLTs) of increased doses of IV clofarabine administered either daily from D1 to D5 for a 28 to 56 day-course or every other day from D1 to D10 for a 28 to 56 day-course.~Secondary endpoints:~To determine response rates, as defined by the 2006 modified IWG criteria, associated with the two different dosing and scheduling of clofarabine in patients with high-risk MDS or AML patients with less than 30% marrow blasts (RAEB-T in FAB MDS classification), previously treated by azacitidine and without erythroid response after 6 cycles of azacitidine.~To evaluate response duration, time to IPSS progression, and loss of RBC transfusion independence in these patients.~To evaluate hospitalization duration, rates of rehospitalization for non-hematological toxicities, severe bleeding or febrile neutropenia.~If treatment is feasible the study will be extended to the phase II part.~Study Objectives:~Primary endpoint:~To confirm safety and hematological toxicity in 14 additional patients. Secondary endpoints~To evaluate response duration, time to IPSS progression, and loss of RBC transfusion independence in these patients.~To evaluate hospitalization duration, rates of rehospitalization for non hematological toxicities, severe bleeding or febrile neutropenia.~To determine the response rate as defined by the 2006 modified IWG criteria.
This study aims to determine the maximal tolerated dose (MTD) and dose limiting toxicities (DLTs) of low dose IV clofarabine for MDS patients after treatment failure of azacitidine.