Assess the safety, tolerability and efficacy of rapamycin in combination with HiVAC in relapsed and refractory patients with aggressive lymphoid malignancies.

Inclusion Criteria:

• Advanced lymphoid leukemia (primary refractory ALL; Relapsed ALL; CML in lymphoid accelerated phase or blast crisis; relapsed or refractory Burkitt's lymphoma; relapsed or refractory T-cell adult leukemia/lymphoma; relapsed or refractory lymphoblastic lymphoma
• >= 18 and <= 65 years of age ECOG performance status 0, 1 Life expectancy >= 4 weeks Able to consume oral medication Required initial laboratory values: Creatinine <= 2.0mg/dL, total or direct bilirubin <= 1.5 mg/dL, SGPT(ALT) <=ULN, glucose < 200 mg/dL, negative pregnancy test for women with child bearing potential

Exclusion Criteria:

• Subjects must not be receiving any chemotherapy agents (except Hydroxyurea)
• Subjects must not have received high-dose Ara-C within 6 months of relapse
• Subjects must not be receiving growth factors, except for erythropoietin
• No currently active second malignancy other than non-melanoma skin cancers
• No subjects with uncontrolled high blood pressure, unstable angina, symptomatic congestive heart failure, MI within the last 6 months or serious uncontrolled cardiac arrhythmia
• Subjects taking Carbamazepine, Rifabutin, Rifampin, Rifapentine, St. John's wort, Clarithromycin, Cyclosporine, Diltiazem, Erythromycin, Telithromycin, Verapamil, Tacrolimus
• Known HIV positivity or AIDS-related illness
• Evidence of cerebellar dysfunction or prior history of cerebellar dysfunction with Ara-C administration
• Pregnant or lactating
• Uncontrolled infection
• Taking fluconazole, voriconazole, itraconazole and ketoconazole currently or within one week of study entry