Abstract: Objective To find out about the occurrence, development and characteristics of immune-related adverse events (irAEs) among tumor patients under immunotherapy with tirelizumab and recommend countermeasures so as to provide reference for early clinical identification and effective response. Methods The clinical data of patients with malignant tumor who received immunotherapy with tirelizumab in the First Affiliated Hospital of Nanjing Medical University between October 1, 2021 and September 30, 2023 was analyzed retrospectively, including the age, gender, disease, concomitant medications, occurrence of irAEs, clinical manifestations, toxicity classification and clinical treatments. The characteristics of IREAS caused by tirelizumab were summarized. Results Among the 424 patients who used tirelizumab, 243 patients (57.31%) had 364 cases of irAES while the rest (42.69%) did not. IrAEs occurred once in 163 cases (67.08%), and twice or more in 80 cases (32.92%). IrAEs involved 11 kinds of systems and organs, the highest incidence is 161cases (44.23%) of endocrine system abnormalities, and 51 cases of blood system abnormalities (14.01%), digestive system damage in 33 cases (9.07%)、Cardiovascular system in 29 cases (7.97%), skin and its accessories in 19 cases (5.22%). There were 345 cases (94.78%) with irAEs of G1-G2 grades, which improved after symptomatic treatment. There were 14 cases (3.85%) of G3 grade, which required hospitalization. Five cases (1.37%) were G4 that involved rescue and treatment. There was no death caused by irAEs. Conclusion Tirelizumab-related irAEs can involve a variety of organs and systems in the body, which can be generally monitored and controlled. Patients can be seriously injured without quick interventions. Early monitoring, quick identification and effective countermeasures can help ensure the safety of medications.

Key words: tirelizumab, tumor treatment, immune-related adverse events(irAEs）, immune checkpoint inhibitors(ICIs), immunotherapy