Galunisertib and Paclitaxel in Treating Patients With Metastatic Androgen Receptor Negative (AR-) Triple Negative Breast Cancer

This phase I trial studies the side effects and best dose of Galunisertib when given together with paclitaxel in treating patients with androgen receptor negative or triple negative breast cancer that has spread to other places in the body. Some tumors need growth factors, which are made by the body's white blood cells, to keep growing. Galunisertib may interfere with growth factors and help cause tumor cells to die. Drugs used in chemotherapy, such as paclitaxel, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving Galunisertib together with paclitaxel may kill more tumor cells.