The purpose of this study is to determine the safety and tolerability of OXi4503 in subjects with relapsed or refractory carcinomas with hepatic tumor burden.

Inclusion Criteria:

1. Histologically or cytologically confirmed carcinoma. Tumor must be relapsed or refractory to standard therapies, or have no acceptable standard therapy.
2. Measurable disease by RECIST criteria.
3. Subjects must be at least 28 days from other investigational therapy and at least 2 weeks after chemotherapy or radiation therapy.
4. Age 18 years or older.
5. Eastern Cooperative Oncology Group (ECOG) Performance Score of less than 1.
6. Life expectancy of greater than 12 weeks.
7. Hemoglobin greater than 10 g/dL.
8. Adequate hepatic function.
9. Adequate renal function.
10. Adequate bone marrow reserve.
11. Able to maintain potassium, calcium and magnesium levels within normal ranges.
12. Must be able to provide written informed consent.
13. All women of childbearing potential (WOCBP) must have a negative serum pregnancy test.
14. WOCBP and fertile men and their partners must agree to use an effective form of contraception during the study and for 90 days after the last dose of study medication.

Exclusion Criteria:

1. Uncontrolled CNS metastases.
2. No other active malignancies.
3. Poorly controlled hypertension.
4. Recent history of serious cardiovascular conditions.
5. Recent history of CVA, TIA, or intermittent claudication.
6. Current anticoagulation therapy.
7. History of cardiac arrhythmias.
8. Abnormal ECG findings.
9. Subjects who require concomitant medications which cause QTc prolongation.
10. Major surgery within 30 days of treatment, or minor surgery within 7 days of treatment.
11. Uncontrolled, clinically significant active infection.
12. Subjects who are pregnant or lactating.
13. Subjects with any other intercurrent medical condition.
14. Subjects with a history of solid organ transplant or bone marrow transplant.