A Phase 2, Multi-Center, Open Label Study Evaluating Clinical Efficacy, Safety, and Pharmacodynamic Effects of Quarfloxacin (CX-3543) in Patients With Relapsed or Refractory B-Cell Chronic Lymphocytic Leukemia (B-CLL)

Inclusion Criteria:

- Patients with B-cell CLL with indications for treatment by National Cancer Institute
(NCI) Working Group criteria.

- Measurable disease (lymphocytes ≥ 5,000/microliter, or palpable lymphadenopathy or
bone marrow involvement > 30%).

- Males and females 18 years of age or older.

- Received a minimum of one prior purine analog-based chemotherapy regimen (e.g.,
fludarabine, cladribine, or pentostatin) and one monoclonal antibody therapy (e.g.,
Campath or Rituxan) but ≤ 4 chemotherapy regimens.

- Patients must have central intravenous (IV) access, or agree to the insertion of a
central line.

- All previous cancer therapies, radiation, hormonal therapy and surgery, must have
been discontinued at least 28 days prior to the start of treatment. Any cytotoxic
chemotherapy must have been discontinued 28 days prior to the start of treatment.
Acute toxicities from prior therapy must have resolved to Grade ≤ 1 above baseline.

- Normal oxygen saturation with pulse oximetry on room air.

- Hemoglobin ≥ 9 gm/dL (may be post-transfusion).

- Platelet count ≥ 25,000/microliter.

- Total bilirubin < 2 X upper limit of normal (ULN), and ALT and AST < 2 x ULN.

- Serum creatinine within normal limits OR calculated creatinine clearance ≥ 60
mL/min/1.73 m2 for patients with creatinine levels above the upper normal limit for
the institution

- ECOG Performance Status ≤ 1.

- Anticipated survival of at least 3 months.

- For men and women of child-producing potential, use of effective contraceptive
methods during the study and for one month after discontinuation of treatment.

- Ability to understand the requirements of the study, provide written informed consent
and authorization of use and disclosure of protected health information, and agree to
abide by the study restrictions and return to the clinic for required assessments.

Exclusion Criteria:

- Pregnant or nursing women.

- Severe chronic obstructive pulmonary disease with hypoxemia or an uncorrectable
pulmonary compromise.

- Seizures not controlled by anticonvulsant therapy.

- Participation in any investigational drug study within 28 days before quarfloxacin
administration.

- Patients with second malignancy requiring active treatment.

- Active symptomatic bacterial, fungal, or viral infection including active HIV or
viral (A, B, or C) hepatitis.

- Clinically significant bleeding event within the last 3 months, unrelated to trauma,
or underlying condition that would be expected to result in a bleeding diathesis.

- Patients who have exhibited allergic reactions to a similar structural compound
(e.g., fluoroquinolones) or formulation (containing buffers and/or polyethylene
glycol).

- Patients with life- or function-threatening CLL complications (e.g., cord
compression, hemolytic crisis, urinary tract obstruction).

- Any illness or condition that in the opinion of the investigator may affect safety of
treatment or evaluation of any of the study's endpoints.