Oral Topotecan to Treat Recurrent or Persistent Solid Tumors

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.