Chimeric Antigen Receptor T-cell Therapies for Multiple Myeloma

Lekha Mikkilineni and James N. Kochenderfer


Multiple myeloma (MM) is a nearly always incurable malignancy of plasma cells, so new approaches to treatment are needed. T-cell therapies are a promising approach for treating MM, with a mechanism of action different than those of standard MM treatments. Chimeric antigen receptors (CARs) are fusion proteins incorporating antigen-recognition domains and T-cell signaling domains. T-cells genetically engineered to express CARs can specifically recognize antigens. Success of CAR T-cells against leukemia and lymphoma has encouraged development of CAR T-cell therapies for MM. Target antigens for CARs must be expressed on malignant cells, but expression on normal cells must be absent or limited. B-cell maturation antigen (BCMA) is expressed by normal and malignant plasma cells. CAR T-cells targeting B-cell maturation antigen have demonstrated significant anti-myeloma activity in early clinical trials. Toxicities in these trials, including cytokine-release syndrome, have been similarto toxicities observed in CAR T-cell trials for leukemia. Targeting postulated CD19+ myeloma stem cells with anti-CD19 CAR T-cells is a novel approach to MM therapy. MM antigens including CD138, CD38, signaling lymphocyte-activating molecule 7 (SLAMF7), and kappa light chain are under investigation as CAR targets. MM is genetically and phenotypically heterogeneous, so targeting of more than one antigen might often be required for effective treatment of MM with CAR T cells. Integration of CAR T cells with other myeloma therapies is an important area of future research. CAR T cell therapies for MM are at an early stage of development but have great promise to improve MM treatment.

  • Submitted June 30, 2017.
  • Accepted August 30, 2017.