Potential immune-related adverse events during dabrafenib and trametinib treatment: A case series of patients with BRAF V600E melanoma

In recent years, BRAF inhibitors (BRAFi) and MEK inhibitors (MEKi), together with immune checkpoint inhibitors (ICIs), have changed the therapeutic strategy of cutaneous melanoma, both in adjuvant and metastatic settings. These inhibitors have significantly improved the clinical outcome for patients with melanoma, including in both BRAF-mutated and BRAF-wild type disease. Some preclinical and clinical studies have revealed that BRAFi and MEKi are able to influence T- and B-cell activation, and to modulate immune system activation within the tumor microenvironment. Dabrafenib and trametinib have been shown to enhance the expression of melanoma antigens on BRAF-mutated cells, and to favor both a cytotoxic and immune response against melanoma cells. Thereby, the present study described a case series of five women treated with BRAFi and MEKi, in both adjuvant and metastatic settings, that experienced potential immune-related adverse events. In particular, these patients exhibited sarcoidosis, mesenteric panniculitis, lymphocytic colitis and neuropathy of phrenic nerve. Considering that T and B cells are responsible for immune-related adverse events, as observed in patients treated with ICIs, the present study suggested a possible role of BRAFi and MEKi as triggers of immune system activation and subsequent immune-related toxicities.