A Dual Response to CD20xCD3 Bispecific Therapy: Remission of Relapsed Diffuse Large B-cell Lymphoma and Improvement in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune cytopenia that may occur in association with lymphoproliferative disorders. In such cases, treatment of the underlying malignancy may influence platelet recovery. CD20xCD3 bispecific antibodies have become important options for relapsed or refractory diffuse large B-cell lymphoma (DLBCL), but their effect on coexisting autoimmune cytopenias is not well defined. We report the case of an 81-year-old woman with relapsed DLBCL arising from an underlying marginal zone lymphoma and longstanding ITP. She achieved complete metabolic remission with initial rituximab, cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone (R-CHOP) and again with polatuzumab vedotin, bendamustine, and rituximab (Pola-BR) after the first relapse, but her thrombocytopenia persisted. Following a second relapse, she was treated with epcoritamab, a CD20xCD3 bispecific T-cell engager. Her course was complicated by steroid-induced hyperglycemia, grade 1 cytokine release syndrome, and adrenal insufficiency, but she achieved complete metabolic remission on follow-up positron emission tomography. Her platelet counts also markedly improved, increased to 142 K/mcL (140-450 K/mcL) from a chronically thrombocytopenic baseline. This case highlights the possibility that bispecific therapy may simultaneously control relapsed DLBCL and secondary ITP through depletion of pathogenic CD20-expression B cells, as well as exhaustion and redirection of T-cells. Further study is needed to determine whether this represents a reproducible therapeutic effect.