TECVAYLI 30 mg Injection TECVAYLI contains Teclistamab, a bispecific T-cell engager (BiTE) antibody that binds to B-cell maturation antigen (BCMA) expressed on the surface of plasma cells, multiple myeloma cells, and some B-lineage cells, and to CD3 expressed on the surface of T-lymphocytes. By simultaneously binding BCMA and CD3, teclistamab brings T-cells into close proximity to myeloma cells, resulting in T-cell activation, redirection of T-cell-mediated cytotoxicity, and lysis of multiple myeloma cells. It is indicated for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.