Teclistamab Induced a Profound Hematologic Response in Light Chain Deposition Disease With Probable Cardiac Involvement.

We report the first case of using teclistamab, a BCMA × CD3 bispecific antibody, in a 63-year-old male with κ-light chain deposition disease (LCDD) involving the kidneys and probably the heart. The patient initially responded to daratumumab-pomalidomide-dexamethasone but experienced hematologic relapse. Salvage therapy with teclistamab induced a rapid and sustained hematologic complete response without cytokine release syndrome or neurotoxicity. Renal and cardiac functions remained stable. This case provides critical early evidence that BCMA-directed immunotherapy may serve as an effective salvage strategy for this rare plasma cell disorder, addressing a significant unmet therapeutic need.