Current Status and Future Prospects of Immune Checkpoint Inhibitors Research in the Treatment of Multiple Myeloma.

Multiple myeloma (MM) is an aggressive hematological tumor characterized by an abnormal proliferation of bone marrow plasma cells accompanied by an overproduction of monoclonal immunoglobulins. The clinical manifestations of MM are varied, with the main ones being anemia, bone pain, renal insufficiency, infections, hemorrhage, neurological symptoms, and hypercalcemia. Chemotherapy, targeted therapy, and stem cell transplantation can provide some relief to patients. However, with the immunodeficiency and immune tolerance that occurs with the progression of the disease, MM is still not completely curable. Immune checkpoint inhibitors (ICIs) provide a new strategy for the treatment of multiple myeloma by blocking the immune escape mechanism of tumor cells and enhancing the ability of T cells to recognize and kill tumors. Currently, immune checkpoint-related therapies such as PD-1/PD-L1, CTLA-4, and TIGIT have attracted extensive attention and research in the field of MM. Due to differences in the genetic characteristics of tumors, the composition of the tumor microenvironment, and the immune status of patients, these therapies face problems such as limited efficacy and immunotoxicity, and the treatment regimens still need to be further optimized. This review summarizes the current research status, challenges and future directions of targeted immune checkpoint therapies for multiple myeloma.