Ribociclib and Doxorubicin in Treating Patients With Metastatic or Advanced Soft Tissue Sarcomas That Cannot Be Removed by Surgery

This phase Ib trial studies the side effects and best dose of ribociclib when giving together with doxorubicin hydrochloride in treating patients with soft tissue sarcomas that has spread to other places or that cannot be removed by surgery (advanced). Ribociclib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as doxorubicin hydrochloride, 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 ribociclib and doxorubicin hydrochloride may work better in treating patients with soft tissue sarcoma.