Inclusion Criteria:

- Patients must have histologically or cytologically confirmed metastatic
adenocarcinoma of the breast

- Patients must have measurable disease, defined as lesions that can be accurately
measured in at least one dimension (longest diameter to be recorded) as >= 20 mm with
conventional techniques or as >= 10 mm with spiral CT scan

- Patients must have progressed on at least one but no more than two prior chemotherapy
regimens for metastatic disease; patients must not have received prior capecitabine
or 5-fluorouracil; patients with hormone-sensitive tumors should have received
hormone treatment and any prior number of hormonal agents will be allowed; patients
with tumors that overexpress HER-2/neu (3+ by immunohistochemistry or amplified by
fluorescent in situ hybridization) should have received herceptin, either in the
adjuvant or metastatic setting, unless there is a contraindication to herceptin
therapy; all prior therapies must have been completed 4 weeks before treatment

- Life expectancy of greater than 3 months

- ECOG performance status =< 2 (Karnofsky >= 50%)

- Leukocytes >= 3,000/μL

- Absolute neutrophil count >= 1,500/μL

- Platelets >= 100,000/μL

- Total bilirubin within normal institutional limits

- AST(SGOT)/ALT(SGPT) =< 2.5 X institutional upper limit of normal

- Creatinine within normal institutional limits OR creatinine clearance >= 60 mL/min

- Patients must have completed radiation treatment > 4 weeks prior to study entry;
previously radiated area(s) must not be the only site of disease

- All major surgical procedures must be completed > 4 weeks prior to study entry;
placement of vascular access device or tissue biopsy will not be considered major
surgery

- Women of child-bearing potential and men must agree to use adequate contraception
(hormonal or barrier method of birth control; abstinence) prior to study entry and
for the duration of study participation; should a woman become pregnant or suspect
she is pregnant while participating in this study, she should inform her treating
physician immediately

- Ability to understand and the willingness to sign a written informed consent document

- Patients must agree to the placement of a central venous catheter in order to receive
the continuous infusion treatment

Exclusion Criteria:

- Patients with only non-measurable disease, defined as all other lesions, including
small lesions (longest diameter < 20 mm with conventional techniques or < 10 mm with
spiral CT scan) and truly non-measurable lesions, which include the following:

- bone lesions

- leptomeningeal disease

- ascites

- pleural/pericardial effusion

- inflammatory breast disease

- lymphangitis cutis/pulmonis

- abdominal masses that are not confirmed and followed by imaging techniques

- cystic lesions

- Patients who have had chemotherapy, hormone therapy, or radiotherapy within 4 weeks
(6 weeks for nitrosoureas or mitomycin C) prior to entering the study or those who
have not recovered from adverse events due to agents administered more than 4 weeks
earlier

- Patients may not be receiving any other investigational agents; patients may not have
received prior GTI-2040

- Patients with known brain metastases should be excluded from this clinical trial
because of their poor prognosis and because they often develop progressive neurologic
dysfunction that would confound the evaluation of neurologic and other adverse events

- History of allergic reactions attributed to compounds of similar chemical or biologic
composition to GTI-2040 or to capecitabine or 5-fluorouracil

- Patients requiring anticoagulant therapy; low-dose anticoagulant (warfarin 1 mg per
day) for the primary prophylaxis of venous catheter-associated thrombosis is
permitted

- Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

- Pregnant women are excluded from this study because GTI-2040 and capecitabine have
the potential for teratogenic or abortifacient effects; because there is an unknown
but potential risk for adverse events in nursing infants secondary to treatment of
the mother with GTI-2040 and capecitabine, breastfeeding should be discontinued if
the mother is treated

- Because patients with immune deficiency are at increased risk of lethal infections
when treated with marrow-suppressive therapy, HIV-positive patients receiving
combination anti-retroviral therapy are excluded from the study because of possible
pharmacokinetic interactions with GTI-2040 or other agents administered during the
study; appropriate studies will be undertaken in patients receiving combination
anti-retroviral therapy when indicated