Teclistamab as an Effective Treatment for Pericardial Effusion in Relapsed Multiple Myeloma: Case Report and a Brief Literature Review.

<bold><italic>Introduction:</italic></bold> Multiple myeloma represents a malignant disorder of plasma cells. Extramedullary relapse in multiple myeloma is a rare occurrence, and pericardial involvement stands as an exceedingly uncommon manifestation. Only a few documented cases of pericardial effusion as an extramedullary relapse presentation of myeloma exist. Bispecific antibodies are emerging as a novel class of immunotherapy drugs for the treatment of relapsed refractory multiple myeloma patients who have experienced failure with four prior lines of therapy. According to a literature review, none of the reported cases with pericardial effusion relapsed myeloma have been treated with bispecific antibodies, given that these drugs have only recently gained approval. <bold><italic>Case Presentation:</italic></bold> We present a rare case of a patient with pericardial effusion resulting from myeloma relapse, treated with teclistamab, a bispecific antibody, and achieving an excellent response. <bold><italic>Conclusion:</italic></bold> Bispecific antibodies, such as teclistamab, show great effectiveness as a treatment for patients with relapsed refractory multiple myeloma, including those with extramedullary disease. [ABSTRACT FROM AUTHOR]