A different anti-BCMA CAR T-cell product known as bb2121 (Bluebird Bio/Celgene) has progressed to a multicenter clinical trial, and on November 16th 2017, the FDA granted a breakthrough designation to bb2121 for the treatment of patients with relapsed/refractory multiple myeloma [45]. Here, TNFRSF17 is linked to plasma cell myeloma.