Paclitaxel and CBT-1(Registered Trademark) to Treat Solid Tumors

Background: * Some cancer cells have a large amount of a protein called P-glycoprotein, which can pump certain chemotherapy drugs out of their cells. This pump may be part of the reason why it is difficult to shrink some cancers with chemotherapy. * In laboratory experiments, the drug CBT-1(Registered Trademark) blocked the P-glycoprotein pump, resulting in accumulation of higher amounts of chemotherapy inside the cancer cells, making the chemotherapy more effective. * Paclitaxel is a cancer drug that has caused tumors to shrink in many types of cancers, including lung, ovarian, breast, renal, cervical and others. Objectives: * To determine whether CBT-1(Registered Trademark) can block the P-glycoprotein pump on cancer cells and whether it inhibits the action of the pump found in normal blood cells and liver tissue. * To evaluate the effectiveness of combination therapy using CBT-1(Registered Trademark) and paclitaxel in treating solid tumors and to determine whether the two drugs together are more effective than paclitaxel alone. Eligibility: -Patients over 18 years of age who have a solid tumor that cannot be treated successfully with standard treatments. Design: -Patients receive CBT-1(Registered Trademark) and paclitaxel in 21-day cycles. Treatment continues for two cycles after all the cancer is gone, or until it is decided to surgically remove some or all of the remaining cancer, or until the cancer has grown to the point where it defined as progressive disease. For each cycle, patients take CBT-1(Registered Trademark) by mouth in three divided doses daily for 7 days. On day 6, paclitaxel is given through a vein over 3 hours. Blood tests are done before starting CBT-1(Registered Trademark) and repeated periodically throughout treatment. Imaging studies computed tomography or magnetic resonance imaging (CT or MRI) are done every two cycles. In addition, for the first cycle only, patients undergo imaging of tumors and normal tissue with a 99mTc-sestami