Abstract The safety and efficacy of CAR T‐cell therapy are unknown in pediatric and adolescent patients with relapsed or refractory primary mediastinal large B‐cell lymphoma (R/R PMBCL) which is associated with dismal prognosis. Here, we present a case report of a 16‐year‐old patient with R/R PMBCL treated with lisocabtagene maraleucel including correlative studies. Patient achieved complete response at 6 months without cytokine release syndrome and immune effector cell‐associated neurotoxicity syndrome. She only experienced mild cytopenias, requiring filgrastim once. This report highlights the safety and efficacy of lisocabtagene maraleucel in this population, warranting prospective studies to improve clinical outcomes.
