Abstract
Immune-checkpoint inhibitors (ICIs) have transformed cancer therapy, but immune-related adverse events (irAEs) remain a major concern. Tislelizumab-a humanised anti-PD-1 monoclonal antibody-has a favourable safety profile; thus, severe hypersensitivity reactions are rarely reported. A 61-year-old male patient was admitted in October 2023 with complaints of intermittent cough and dyspnoea for 1 year, aggravation accompanied by fatigue and bloody sputum for more than 20 days. Imaging and histopathological examinations confirmed extensive-stage metastatic small-cell lung carcinoma (SCLC). In line with the 2023 World Conference on Lung Cancer (WCLC) report and patient's financial constraints, first-line therapy with tislelizumab plus carboplatin-etoposide was initiated. Seven minutes after tislelizumab infusion began, the patient experienced acute dyspnoea, loss of consciousness, and unrecordable blood pressure and oxygen saturation. The infusion was stopped immediately, and dexamethasone, diphenhydramine, epinephrine, and cardiopulmonary resuscitation were administered. After a few minutes and subsequent aggressive symptomatic treatment, the patient's vital signs stabilized. No prior allergy history or contraindication had been noted; other potential causes of shock were excluded. Given the temporal relationship and rapid response to anti-allergic therapy, anaphylactic shock secondary to tislelizumab was diagnosed. This case underscores that tislelizumab can trigger life-threatening hypersensitivity, even on first exposure. Oncologists should maintain a high index of suspicion, ensure close monitoring during initial infusions, and have resuscitation measures immediately available. Early recognition and prompt management are pivotal to minimise morbidity. Further pharmacovigilance data are needed to quantify the true incidence and identify predisposing factors for tislelizumab-related anaphylaxis.