SNX-5422 to Treat Solid Tumor Cancers and Lymphomas

Background: SNX-5422 is an experimental drug that inhibits a protein called Hsp90, which is important for the growth of tumor cells. SNX-5422 has shown some activity against tumors in the laboratory and animal studies. Objectives: To determine the highest safe dose, or maximum tolerated dose (MTD), of SNX-5422 that can safely be given to patients with solid tumor cancers and lymphomas when taken twice a week. To learn how the body's blood and tissue cells react to SNX-5422. To examine the effects of SNX-5422 on tumors and lymphomas. Eligibility: Patients 18 years of age or older who have solid tumor cancers or lymphomas that do not respond to standard therapy or for whom no acceptable standard treatment is available. Design: SNX-5422 is taken by mouth twice a week in 28-day cycles. Treatment may continue as long as the cancer does not worsen and side effects are acceptable. Three to six patients are enrolled in the study at a time. Each group is given a higher dose of SNX-5422 than the previous, as long as the preceding dose was tolerated and until the MTD is determined. When the MTD is found, six more patients are enrolled at that dose level. During the treatment period, patients undergo the following tests and procedures: * Clinic visits for a physical examination each treatment cycle to check on health status. * Blood tests for routine laboratory values, to determine how the body handles SNX-5422, and to examine the effects of SNX-5422 on blood cells and other targets. * Urine tests as needed, depending on the results of blood tests. * CT scans, or other imaging tests every 8 weeks to evaluate the tumor response to treatment. * Tumor biopsy (surgical removal of a tissue sample for examination under a microscope) before the first dose of SNX-5422 and again 24 hours after the first dose to see how the drug affects the tumor. This test is optional.