Teclistamab for the treatment of autoantibody-mediated coagulation disorders.

BACKGROUND: Teclistamab is a bispecific monoclonal antibody that targets B cell maturation antigen (BCMA) on plasma cells and other B lineage cells and CD3 on T cells, thereby redirecting cytotoxic T cells to eliminate BCMA-expressing antibody-producing cells. Autoantibody-mediated coagulation disorders are often driven by long-lived antibody-producing cells that may persist despite conventional immunosuppression or B cell depletion. OBJECTIVE: To investigate whether teclistamab represents a treatment option for patients with refractory or rapidly progressive autoantibody-mediated coagulation disorders. METHODS: We retrospectively analyzed seven patients with autoantibody-mediated coagulation disorders treated with teclistamab. Diagnoses included acquired von Willebrand disease (n=2), acquired factor XI deficiency (n=2), and catastrophic antiphospholipid syndrome (CAPS; n=3). Five patients had an underlying paraprotein, whereas two CAPS patients had no detectable paraprotein. RESULTS: All seven patients achieved complete remissions (median time to remission: 24 weeks [range: 2-35]) following teclistamab. In the four patients with acquired von Willebrand disease or factor XI deficiency, improvement in the disease-defining coagulation parameter and cessation of bleeding were observed following initiation of teclistamab. In the three patients with CAPS disappearance of antiphospholipid antibodies or normalization of the aPTT-LA was observed and accompanied by clinical stabilization without further thromboembolic events. Treatment was generally well tolerated. Three patients developed grade 1 cytokine release syndrome. One patient developed transient colitis while another patient experienced reversible seronegative inflammatory joint symptoms. All patients received immunoglobulin replacement. CONCLUSION: Teclistamab treatment was associated with complete remissions in patients with autoantibody-mediated coagulation disorders. These observations warrant further evaluation of teclistamab in selected patients.