BCMA CAR T cells in a patient with relapsing idiopathic inflammatory myositis after initial and repeat therapy with CD19 CAR T cells.

CD19 chimeric antigen receptor (CD19 CAR) T cell therapy has been shown to induce stable drug-free remission in patients with refractory autoimmune disease. The management of potential relapses is currently unclear. Here we report on a 45-year-old woman with treatment-refractory Jo-1-associated anti-synthetase syndrome, who initially achieved disease remission after CD19 CAR T cell therapy but then experienced disease relapse after 9 months. After reinfusion of the same product, CAR T cells failed to expand and T cells targeting the CD19 CAR were detected. Despite full-dose lymphodepletion, no clinical response was observed. After bridging with anti-CD38 antibody daratumumab, which was efficacious with limited durability, plasma-cell-targeting B-cell maturation antigen (BCMA) CAR T cell therapy was performed. BCMA CAR T cells expanded, cleared plasma cells in lymphoid tissue, reduced autoantibody levels and re-induced stable drug-free remission. This case highlights the challenges in CAR T cell reinfusion, the potential of alternative targets and products, and suggests that the depletion of plasma cells may enhance therapeutic outcomes in patients who become treatment-refractory.