Epcoritamab as bridging therapy to successful second allogeneic HSCT in relapsed DLBCL after UCBT and CAR T cell therapy.

A 53-year-old woman experienced relapse of diffuse large B cell lymphoma (DLBCL) 16 years after achieving a first complete metabolic response (CMR). Despite initially being refractory to salvage chemotherapy, she achieved a second CMR and underwent umbilical cord blood transplantation (UCBT). On day 119 post-transplantation, she experienced a second relapse and received chimeric antigen receptor T (CAR T) cell therapy, achieving a third remission without cytokine release syndrome or graft-versus-host disease (GVHD). However, a third relapse occurred seven months after CAR T cell therapy. Epcoritamab treatment was initiated, resulting in CMR without severe complications. Subsequently, the patient underwent curative unrelated allogeneic peripheral blood hematopoietic stem cell transplantation (HSCT). She experienced no severe transplant-related complications, including serious GVHD or infections. She has remained in CMR for > 1 year after the second transplant. Epcoritamab appears to be an effective and safe treatment option for DLBCL relapse, even after both UCBT and CAR T cell therapy, suggesting that bridging therapy with epcoritamab followed by a second allogeneic HSCT may achieve long-term survival.