CD19 and diffuse large B-cell lymphoma: Loncastuximab tesirine (loncastuximab tesirine‐lpyl [Lonca]) is an antibody‐drug conjugate (ADC) comprising a humanised anti‐CD19 antibody conjugated to a pyrrolobenzodiazepine dimer cytotoxin, SG3199, and is indicated for patients with R/R DLBCL, DLBCL arising from low‐grade lymphoma and high‐grade B‐cell lymphoma after at least two systemic treatments [11, 12, 13, 14].