Supplementary Material for: Early neurotoxicity following a single dose of brentuximab in a patient with Epstein bar virus driven lymphoma: A Case Report

Background:
Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) present unique challenges in immunocompromised patients. Neurotoxic complications typically arise after prolonged exposure and tend to manifest as peripheral neuropathy. This case describes acute encephalopathy shortly after a brief course, an uncommon and severe adverse effect.
Case Report:
We describe a 17-year-old Hispanic male with EBV-associated LPD in the setting of complex autoimmune vasculitis and immunosuppression. Disease was unresponsive to multiple therapies including rituximab and chemotherapy, but eventually responded to a course of SMILE (steroid-dexamethasone, methotrexate, ifosfamide, L-asparaginase, etoposide). Brentuximab vedotin maintenance was initiated to secure remission. However, 7 days post-initiation, he developed culture-negative sepsis which progressed to acute encephalopathy and multiorgan failure. Infectious work-up along with Neurological evaluation, including imaging and cerebrospinal fluid analysis, did not identify an alternative etiology.
Conclusion:
This case highlights a rare instance of early brentuximab vedotin-induced encephalopathy and underscores the need for close neurological monitoring in high-risk patients.