Steroid-refractory severe immune-related mucositis following adjuvant anti-PD-1 therapy for resectable melanoma: a case report

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and are increasingly used, also in the adjuvant and neoadjuvant settings. ICIs, however, can induce immune-related adverse events (irAEs), which range from mild to life-threatening. As the use of ICIs expands, prompt identification and management of especially severe and life-threatening irAEs are crucial. We report a case of grade 4 steroid-refractory immune-related mucositis in a 60-year-old male treated with pembrolizumab following complete resection of stage IIIC melanoma. The patient received seven courses of adjuvant pembrolizumab without adverse events until 2 weeks after the seventh dose, when he presented with acute respiratory distress, dysphagia, and dyspnea. Examination revealed significant throat swelling and mucosal edema. Despite initial treatment with high-dose steroids, the patient's condition deteriorated, and he was admitted to the ICU for intubation and close monitoring. Infliximab was administered for steroid-refractory mucositis, resulting in rapid symptom resolution and successful extubation 5 days later. This case highlights the challenges in managing severe steroid-refractory irAEs. The rapid response to infliximab suggests the benefit of early intervention with alternative immunosuppressive agents in severe irAEs. Increased awareness of rare irAEs is essential for optimizing treatment and improving outcomes for patients receiving ICIs.