Successful Use of Epcoritamab in Refractory Diffuse Large B-Cell Lymphoma with Central Nervous System Involvement: A Case Report.

Introduction: Diffuse large B-cell lymphoma (DLBCL) with central nervous system (CNS) involvement carries an extremely poor prognosis, particularly in patients' refractory to standard immunochemotherapy. Although bispecific antibodies are generally considered to have limited efficacy in CNS disease, this case suggests a potential clinical benefit of epcoritamab in refractory DLBCL with CNS involvement. Case Presentation: We describe the case of a 71-year-old man with primary bone marrow DLBCL refractory to dose-adjusted EPOCH-R. Despite treatment with high-dose methotrexate and intrathecal chemotherapy, the disease progressed rapidly, with involvement of the CNS. Given the limited efficacy of standard salvage regimens and the urgent need for disease control, epcoritamab, a CD20×CD3 bispecific antibody, was initiated along with the bridging therapy. Bispecific antibodies are generally considered ineffective in CNS disease because of poor blood-brain barrier penetration, and such patients are typically excluded from clinical trials. However, epcoritamab induced a rapid systemic response along with partial neurological improvement. Conclusion: This case highlights the potential role of bispecific antibody therapy in refractory DLBCL with CNS involvement, an area of significant unmet clinical need.