Targeting BCMA in Plasmablastic Lymphoma With Teclistamab: A Case Study of Three Patients.

Plasmablastic lymphoma (PBL) is a rare subtype of non-Hodgkin lymphoma (NHL) with limited standard therapeutic options and poor outcomes. PBL typically lacks expression of the B-cell antigens CD20 or CD19 and, accordingly, has not benefited from the incorporation of B-cell-targeted antibodies. However, recent reports demonstrate that B-cell maturation antigen (BCMA) is expressed in most patients with PBL. BCMA is an established therapeutic target in multiple myeloma. Herein, we describe the clinical course of 3 patients with PBL found to express BCMA by immunohistochemistry who were treated with the BCMA×CD3 bispecific antibody teclistamab after developing disease refractory to at least 2 lines of standard therapy. A complete response was observed in 2 patients: 1 patient remains in remission after 2 years of teclistamab treatment, while the second achieved a complete response after 1 cycle of teclistamab, subsequently underwent allogeneic stem cell transplantation, and developed relapsed PBL 3 months post-transplant. The third patient developed a small bowel obstruction and transitioned to hospice care after 1 cycle of teclistamab. This case series adds to the growing evidence that BCMA is expressed in a considerable subset of patients with PBL and suggests that BCMA may serve as a potential molecular biomarker in PBL for further investigation of available BCMA-directed therapies.