Successful Treatment of Cytokine Release Syndrome with IL-6 Blockade in a Patient Transitioning from Immune-Checkpoint to MEK/BRAF Inhibition: A Case Report and Review of Literature

There are now multiple targeted and immunotherapies available for the treatment of metastatic melanoma. Although these agents have dramatically improved the survival of patients, the appropriate sequencing and the safety during the transition between these drugs remains unknown. Recently two cases of cytokine release syndrome (CRS) following transition from immune-checkpoint inhibitors to BRAF and MEK inhibitors (BRAFi/MEKi) in patients with metastatic melanoma have been reported. CRS is a systemic cytokine-driven inflammatory reaction, previously well reported in chimeric antigen receptor T-cell therapies for hematologic malignancies. Here, we report a third case in which severe CRS resistant to glucocorticoid therapy following transition to a MEKi/BRAFi was treated successfully with tocilizumab, an interleukin-6 (IL-6) inhibitor. CRS should be on the differential diagnosis of immune-related adverse events of immunotherapies or targeted cancer therapies for metastatic melanoma, and clinicians in multiple disciplines should be aware of this rare complication and the potential benefits of IL-6 blockade.