Repeat-Dose of Forodesine Hydrochloride (BCX-1777) Infusion in Patients With Advanced T-Cell Leukemia

Inclusion Criteria:

* Documented T-cell leukemia (precursor T-lymphoblastic leukemia/lymphomia or T-PLL)
* Failure to have responded to one or more standard regimens for their disease.
* Performance status of \<=2 by Eastern Cooperative Oncology Group (ECOG) criteria
* All ages are eligible
* Life expectancy of at least 3 months
* Adequate liver function (aspartate transaminase \[AST\] and/or alanine transaminase \[ALT\] not \>3 times upper limits or normal \[ULN\])
* Adequate kidney function (calculated creatinine clearance \>50 mL/min)
* Negative urine pregnancy test within 2 to 7 days prior to the start of study treamtment in females of childbearing potential
* Females of childbearing potential and males must be willing and able to use an adequate method of contraception to avoid pregnancy for the duration of the study
* Signed informed consent/assent form (ICF) prior to start of any study specific procedures

Exclusion Criteria:

* Patients with known HIV infection or human T-cell leukemia virus type (HTLV-1)
* Patients with known Hepatitis B and/or Hepatitis C active infection
* Patients with active CMV infection
* Tumor-related central nervous system (CNS) leukemia requiring active treatment
* Active serious infection not controlled by oral or IV antibiotics
* Treatment with any investigational anti-leukemic agent or chemotherapy agent within 7 days prior to study entry, unless full recovery from side effects has occurred.
* Rapidly progressive disease with compromised organ function judged to be life-threatening by the investigator
* Concurrent treatment with other anticancer agents (corticosteroid use will not be excluded, but patient must remain on the stable dose)
* Cutaneous T-cell lymphoma (CTCL) diagnosis (including Sezary Syndrome)
* Pregnant and/or lactating women