Dose Escalation Study of Clofarabine in Patients With Relapsed or Refractory Low Grade or Intermediate-Grade B-Cell Lymphoma

Inclusion Criteria:

* Adult patients who are at least 18 years old
* Histologically confirmed low grade or intermediate-grade B-cell lymphoma
* Relapsed or refractory to at least one standard chemotherapy regimen. Patients who have received Rituximab alone without having received a cytotoxic agent are not eligible.
* Measurable disease, defined by the Cheson lymphoma criteria.
* Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2
* Life expectancy greater than 12 weeks
* Laboratory values obtained ≤2 weeks prior to entry

  * Absolute neutrophil count (ANC) ≥ 1000 x 10 9/L
  * White blood cell (WBC) count \> 2.5 x 10 9/L
  * Platelets ≥ 75 x 10 9/L
  * Hemoglobin (Hg) \> 9.0 g/dL
  * Total bilirubin ≤2.0 mg/dL
  * Aspartate transaminase (AST)/alanine transaminase (ALT) ≤3 × upper limit of normal (ULN)
  * Serum creatinine ≤2.0 mg/dL
* Normal cardiac function, defined as an ejection fraction ≥45% determined by pretreatment radionuclide ventriculography (RVG) or echocardiogram.
* Capable of understanding the investigational nature, potential risks and benefits of the study, and able to provide valid informed consent.
* Female patients of childbearing potential must have a negative serum pregnancy test within 2 weeks prior to enrollment.
* Male and female patients must use an effective contraceptive method during the study and for a minimum of 6 months after study treatment.

Exclusion Criteria:

* Previously untreated B-cell lymphoma.
* Received previous treatment with clofarabine.
* Patients with known AIDS-related or HIV-positive lymphoma.
* Autologous bone marrow or stem cell transplant within 6 months of study entry.
* Prior radiotherapy to the only site of measurable disease.
* Any medical condition that requires chronic use of oral high-dose corticosteroids greater than 20 mg/day prednisone.
* Active autoimmune thrombocytopenia.
* Use of investigational agents within 30 days or any anticancer therapy within 3 weeks before study entry. The patient must have recovered from all acute toxicities from any previous therapy.
* Patients with an active, uncontrolled systemic infection considered to be opportunistic, life threatening, or clinically significant at the time of treatment or with a known or suspected fungal infection (ie, patients on parenteral antifungal therapy).
* Active secondary malignancy.
* Pregnant or lactating patients.
* Any significant concurrent disease, illness, or psychiatric disorder that would compromise patient safety or compliance, interfere with consent, study participation, follow up, or interpretation of study results.
* Patients with active or untreated central nervous system (CNS) lymphoma.