Camrelizumab-induced anaphylactic reaction: a case report and literature review

Camrelizumab is an immune checkpoint inhibitor clinically used to treat various types of tumours. In this study, the authors provided the first report of a case of an anaphylactic reaction induced by camrelizumab in the treatment of a patient with squamous cell carcinoma of the floor of the mouth. The patient, a 58-year-old man, was diagnosed with advanced squamous cell carcinoma of the floor of the mouth, with cancer infiltration and multiple metastases. He underwent treatment for nine cycles, in which cycles 1-5 he received camrelizumab, albumin-bound paclitaxel, and cisplatin (200 mg of camrelizumab each time, every 3 weeks), with no adverse reactions; in cycle 6, he received albumin-bound paclitaxel and cisplatin, with no adverse reactions; and in cycles 7-9, he received camrelizumab and albumin-bound paclitaxel. However, 30 min after 8th administration of camrelizumab (cycle 9), he suddenly developed sweating, a pale complexion, clamminess and cyanosis of the limbs (percutaneous arterial oxygen saturation [SpO₂] = 82%, blood pressure [BP] = 79/49 mmHg, heart rate [HR] = 83 beats/min [bpm] and respiratory rate [RR) = 12 bpm). The patient underwent intravenous infusion of methylprednisolone (80 mg) combined with dopamine to boost the BP; he regained consciousness 20 min later, and many parts of his skin appeared smooth, with no desquamation and accompanied by itching erythema, especially on the upper limbs. Approximately 2 h after treatment, the patient's skin erythema subsided (vital sign monitoring results: SpO₂ = 100%, BP = 122/84 mmHg, HR = 91 bpm and RR = 17 bpm); the patient did not complain about his obvious discomfort. Despite the rarity of acute anaphylactic reactions among immune-related adverse reactions, great importance should be given to anaphylactic reactions of camrelizumab due to its extensive clinical application.