Nivolumab PD-1 Blockade As Bridge to Allogeneic Stem Cell Transplant (HSCT) in Gray-Zone Lymphoma: Case Report

Mediastinal Gray-zone lymphoma (GZL) is a rare entity of lymphoma, with a typical overlapping in terms of biologic and morphologic features between classic Hodgkin lymphoma (cHL) and primary mediastinal large B-cell lymphoma (PMBCL). The therapeutic approaches for these patients remain controversial, and most standard approaches include a combination of chemotherapy, immunotherapy, and, recently, radiation. Unfortunately, overall survival (OS) and progression free survival (PFS) remain dreary. This case report will discuss an adult patient with mediastinal GZL treated as first line with chemotherapy approaches; after an initial lack of response, we decided for a strategy with the anti PD-1 blockade Nivolumab as bridge to the allogeneic hematopoietic stem cell transplant (HSCT). The patient obtained a complete response before the HSCT maintaining this result after the HSCT with temporary grade I and II GVHD, suggesting the important role of the checkpoint inhibitor in this setting of patients. Clinical trials, with larger groups of patients, and longer follow-up are needed to better define safety and prognostic impact of anti PD1 and subsequent allogeneic HCT for the treatment of GZL.