PDCD1 and diffuse large B-cell lymphoma: However, in a trial evaluating intravenous PD-1 blockade for relapsed DLBCL (diffuse large B-cell lymphoma), treatment-related adverse events were nonetheless recorded in 62% with 24% experiencing grade ≥3 toxicities.13 Intraventricular immunochemotherapy could constitute a less hematotoxic alternative—particularly in the elderly and other cohorts who cannot tolerate aggressive systemic polychemotherapy.