Background: * Some types of cancer cells that have hormone receptors on their surfaces need the hormone estrogen to grow. The drug tamoxifen blocks estrogen from binding to the tumor cells, which helps to slow or stop the growth of cancer. Tamoxifen has been approved for treatment of certain types of estrogen-linked cancers, such as breast and ovarian cancer. * The experimental drug Z-Endoxifen HCl (endoxifen) is related to tamoxifen, and has been shown to work against similar estrogen-linked cancers. In many cancer patients, tamoxifen is turned into endoxifen by enzymes in the liver; however, not all people have the liver enzymes that can turn tamoxifen into endoxifen, which means that the drug cannot work properly. Taking certain other drugs at the same time as tamoxifen can also keep it from turning into endoxifen. Researchers are interested in determining whether endoxifen tablets are effective in slowing or stopping tumor growth in individuals whose hormone-linked tumors have not responded to standard treatment. Objectives: \- To test the safety and effectiveness of daily endoxifen in individuals with hormone receptor positive solid tumors that have not responded to standard treatment. Eligibility: \- Individuals at least 18 years of age who have been diagnosed with hormone receptor positive solid tumors (breast or other tumors), desmoid tumors, or gynecologic tumors that have not responded to standard treatment. Individuals with breast cancer must have had at least one prior chemotherapy regimen and one prior hormonal regimen for metastatic disease. Design: * Participants will be screened with a full medical history (including prior hormone use) and physical examination, as well as blood and urine tests, tumor imaging studies, and an eye examination. * Participants will take endoxifen tablets daily for 28-day cycles of treatment, and will be asked to keep a medication diary to record any side effects. * Participants will have regular clinic visits with blood and urine samples and imaging studies to evaluate the cancer's response to treatment. * Participants will continue to take endoxifen for as long as the cancer responds to the treatment.
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Establish safety and MTD of Z-endoxifen
Timeframe: 28 days (1 cycle)