Atezolizumab-induced anaphylactic shock in a patient with hepatocellular carcinoma undergoing immunotherapy: A case report

BACKGROUND: Atezolizumab is a programmed death ligand 1 (PD-L1) inhibitor, and its combination with bevacizumab has been proven an effective immunotherapy for unresectable hepatocellular carcinoma (HCC). Treatment with immune checkpoint inhibitors (ICIs) can lead to hypersensitivity reactions; however, anaphylactic shock is rare. We present a case of life-threatening anaphylactic shock during atezolizumab infusion and performed a relevant literature review. CASE SUMMARY: A 75-year-old man was diagnosed with HCC recurrence after hepatectomy. He was administered immunotherapy with atezolizumab plus bevacizumab after an allergy to a programmed death-1 (PD-1) inhibitor. The patient showed a sudden onset of dizziness, numbness, and lack of consciousness with severe hypotension during atezolizumab infusion. The treatment was stopped immediately. The patient’s symptoms resolved after 5 mg dexamethasone was administered. Because of repeated hypersensitivity reactions to ICIs, treatment was changed to oral targeted regorafenib therapy. CONCLUSION: Further research is necessary for elucidating the hypersensitivity mechanisms and establishing standardized skin test and desensitization protocols associated with PD-1 and PD-L1 to ensure effective treatment with ICIs.