Inclusion Criteria:

• Patient provides written informed consent prior to study-specific screening procedures, with the understanding that the patient has the right to withdraw from the study at any time, without prejudice.
• Male or female patients.
• Patient is at least 18 years of age with recurrent or persistent solid tumors.
• Patient has adequate hematologic function (absolute neutrophil count [ANC] >= 1500/mL and platelets >= 100,000/mL), adequate renal function (serum creatinine < 2.0 mg/dL; calculated creatinine clearance > 40 mL/min), and adequate hepatic function (serum bilirubin <= 1.5 mg/dL and transaminases <= 3 times the upper limit of normal [3 x ULN]).
• Patient has Eastern Oncology Cooperative Group (ECOG) performance status of <= 2.
• Patient has a life expectancy of at least 3 months at time of enrollment.
• Patient has no medical problems, unrelated to the malignancy, of sufficient severity which would limit full compliance with the study or which would expose him/her to undue risks.
• Patient has received no more than 2 prior treatment regimens prior to enrollment including chemotherapy, hormonal therapy, biologic therapy, and immunotherapy.
• Patient has a negative serum or urine pregnancy test within 7 days prior to starting therapy (if a female of childbearing potential).

Exclusion Criteria:

• Patient is a pregnant or lactating woman. Women of childbearing potential with either a positive or no pregnant test (serum or urine) at baseline.

Women of childbearing potential not using a reliable and appropriate contraceptive method will be excluded. (Postmenopausal women must have been amenorrheic for at least 12 months to be considered of non-childbearing potential.) Patients must agree to continue contraception for 30 days from the date of the last study drug administration.

• Patient has serious, uncontrolled, concurrent infection(s).
• Patient has received whole pelvic or extended field radiation therapy within 4 weeks of enrollment. Patients who have not fully recovered or whose acute toxicity related to prior radiotherapy has not returned to baseline are ineligible.
• Patient has received myelosuppressive chemotherapy within the last 4 weeks or has not recovered from the myelosuppressive effects of recent chemotherapy.
• Patient has received another investigational agent within 4 weeks prior to study enrollment.
• Patient has known hypersensitivity to topoisomerase I inhibitors.
• Patient is unable to swallow a capsule or has a disease known to affect drug absorption, such as short gut syndrome or active radiation enteritis.
• Patient has received drugs known to alter absorption such as antacids, proton pump blockers (eg, omeprazole), or H2 receptor antagonists (eg, cimetidine). A washout period of one week (7 days) is required prior to initiating study medication.