SX-682

This phase I trial tests the safety and side effects of SX-682 in combination with standard of care treatment carfilzomib, daratumumab-hyaluronidase, and dexamethasone in treating patients with multiple myeloma that has come back after a period of improvement (relapsed) or that has not responded to previous treatment (refractory). SX-682 works by blocking certain sites on cells that suppress the ability of the immune system to destroy tumor cells. Blocking those specific sites allows other cells of the immune system to become "free" to kill tumor cells. Carfilzomib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Daratumumab is in a class of medications called monoclonal antibodies. It binds to a protein called CD38, which is found on some types of immune cells and tumor cells, including myeloma cells. Daratumumab may block CD38 and help the immune system kill tumor cells, while hyaluronidase helps to deliver daratumumab to CD38-expressing tumor cells through a subcutaneous injection. Dexamethasone is in a class of medications called corticosteroids. It is known to kill myeloma cells and is also used to reduce inflammation and lower the body's immune response to monoclonal antibodies like dratumumab and help lessen its side effects. Giving SX-682 in combination with carfilzomib, daratumumab-hyaluronidase and dexamethasone may be safe and tolerable in treating patients with relapsed or refractory multiple myeloma