Cytokine release syndrome following durvalumab and tremelimumab in advanced hepatocellular carcinoma: A case report with cytokine and damage‐associated molecular pattern analysis

Abstract Cytokine release syndrome (CRS) is a systemic inflammatory syndrome that causes fatal circulatory failure due to hypercytokinemia, and subsequent immune cell hyperactivation caused by therapeutic agents, pathogens, cancers, and autoimmune diseases. In recent years, CRS has emerged as a rare, but significant, immune‐related adverse event linked to immune checkpoint inhibitor therapy. Furthermore, several previous studies suggested that damage‐associated molecular patterns (DAMPs) could be involved in malignancy‐related CRS. In this study, we present a case of severe CRS following combination therapy with durvalumab and tremelimumab for advanced hepatocellular carcinoma, which recurred during treatment, as well as an analysis of cytokine and DAMPs trends. A 35‐year‐old woman diagnosed with hepatocellular carcinoma underwent a partial hepatectomy. Due to cancer recurrence, she started a combination of durvalumab and tremelimumab. Then, 29 days post‐administration, she developed fever and headache, initially suspected as sepsis. Despite antibiotics, her condition worsened, leading to disseminated intravascular coagulation and hemophagocytic syndrome. The clinical course and elevated serum interleukin‐6 levels led to a CRS diagnosis. Steroid pulse therapy was administered, resulting in temporary improvement. However, she relapsed with increased interleukin‐6, prompting tocilizumab treatment. Her condition improved, and she was discharged on day 22. Measurements of inflammatory cytokines interferon‐γ, tumor necrosis factor‐α, and DAMPs, along with interleukin‐6, using preserved serum samples, confirmed marked elevation at CRS onset. CRS can occur after the administration of any immune checkpoint inhibitor, with the most likely trigger being the release of DAMPs associated with tumor collapse.