Case report and literature review of severe adverse reactions following pucotenlimab treatmentNew drug treatment linked to severe neurological reactions

Immune checkpoint inhibitors (ICIs) have been widely utilized in patients with cancer and established as a standard therapeutic modality for various solid tumors. Although generally well tolerated, ICIs can induce unique immune-related adverse events (irAEs) affecting systemic systems and organs, posing a significant challenge in clinical oncology practice. Neurological immune-related adverse events (N-irAEs) are relatively rare, but the clinical management of high-grade N-irAEs is extremely challenging and potentially life-threatening. Concurrently, the nonspecific manifestations and extensive differential diagnoses of N-irAEs render their diagnosis highly difficult, which may result in suboptimal clinical management. Herein, we report on a case of a patient with advanced breast cancer who developed severe adverse reactions subsequent to treatment with pucotenlimab and was diagnosed with anti-aquaporin 4 antibody (AQP4-Ab)-positive neuromyelitis optica spectrum disorder (NMOSD) following multidisciplinary discussion. Despite prompt administration of high-dose methylprednisolone and plasma exchange therapy, the patient’s neurological symptoms progressively worsened, leading to multiple organ dysfunction syndrome and subsequent death. A literature review on N-irAEs is also presented.