Case Report: CAR-T therapy for relapsed diffuse large B-cell lymphoma in a patient with pre-existing Parkinson's disease-unfolding clinical challenges.

Chimeric antigen receptor T-cell (CAR-T) therapy has transformed the outcomes for relapsed/refractory diffuse large B-cell lymphoma (DLBCL). However, immune effector cell-associated neurotoxicity syndrome (ICANS) remains a concern. Pre-existing neurological disorders such as Parkinson's disease (PD) introduce additional, poorly studied challenges due to the risk of unpredictable complications. We report a 62-year-old man with relapsed DLBCL and pre-existing PD who was treated with lisocabtagene maraleucel. Baseline assessments by neurology, physiotherapy, and speech-language teams enabled tailored monitoring, including use of a modified Immune Effector Cell-Associated Encephalopathy (ICE) score. His dopaminergic regimen was optimised prior to therapy. Following lymphodepletion and CAR-T infusion, he experienced grade 1 cytokine release syndrome, which resolved with tocilizumab and ward-based supportive care. Although a stable partial response was observed on PET-CT scan at 1 and 3 months, the absence of ICANS or PD worsening up to his most recent follow-up on Day +86 suggests that CAR-T therapy can be safely delivered in patients with pre-existing PD when tailored strategies are applied, including a multidisciplinary approach, modified neurotoxicity monitoring, and careful selection of the CAR-T construct. Further studies and longer follow-up are needed to clarify long-term safety in this population.