Idarubicin, Cytarabine, and Tipifarnib in Treating Patients With Newly Diagnosed Myelodysplastic Syndromes or Acute Myeloid Leukemia

PRIMARY OBJECTIVES: I. To determine the tolerability of the combination of R115777 (Zarnestra™) and Idarubicin plus cytarabine by defining the DLT and MTD. (Phase I) II. To determine the efficacy of the combination of Idarubicin, cytarabine and ZARNESTRA in patients with high-risk MDS and AML. (Phase II) OUTLINE: This is a dose-escalation study of tipifarnib. Patients are stratified according to age (\< 50 versus ≥ 50) and, in patients ≥ 50 years of age, cytogenetics (diploid versus unfavorable). INDUCTION THERAPY: PHASE I: Patients receive cytarabine IV continuously on days 1-3 (or 1-4), idarubicin intravenous (IV) over 1 hour on days 1-3, and oral tipifarnib twice daily on days 1-21. Treatment repeats every 21 days for up to 2 courses in the absence of disease progression or unacceptable toxicity. Cohorts of 6 patients receive escalating doses of tipifarnib until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose-limiting toxicity. PHASE II: Patients receive cytarabine, idarubicin, and tipifarnib as in phase I at the MTD. Patients in both phases who respond to induction therapy proceed to consolidation maintenance therapy. CONSOLIDATION MAINTENANCE THERAPY: Patients receive consolidation therapy comprising cytarabine IV continuously on days 1-3, idarubicin IV over 1 hour on days 1-2, and tipifarnib twice daily on days 1-14. Treatment repeats every 4-6 weeks for 5 courses in the absence of unacceptable toxicity. Patients then begin maintenance therapy comprising oral tipifarnib twice daily on day 1-21. Treatment repeats every 4-6 weeks for 6 courses in the absence of unacceptable toxicity.