Abstract
Hemophagocytic lymphohistiocytosis (HLH) has been only rarely reported in patients with BRAF-mutated advanced melanoma treated with targeted therapies and never with first-line dabrafenib/trametinib combination thus far. Two patients treated with first-line dabrafenib and trametinib combination therapy for metastatic melanoma presented with sudden occurrence of fever, cytopenia, rhabdomyolysis, hepatic cytolysis, hypertriglyceridemia and very high ferritin levels after few weeks of treatment, associated with concomitant epstein-barr virus (EBV) reactivation in one patient. In both cases, drug-induced HLH was primarily considered owing to a high H-score and the absence of other etiology. Patients rapidly improved after treatment discontinuation associated with oral steroids in one patient and did not relapse after subsequent treatment resumption with a concurrent anti-BRAF/anti-MEK combination. In metastatic melanoma HLH may occur either spontaneously in the absence of any treatment as a paraneoplastic condition, related to an intercurrent infection or drug-induced mainly with various immunotherapy or with dabrafenib and trametinib following immunotherapy. However, such observations are scarce and these are the first cases of HLH occurring during first-line treatment with dabrafenib and trametinib in advanced melanoma to our knowledge. Pathomechanisms remain to be elucidated since triggering factors may encompass the treatment itself but also other significant actors including viral reactivation along with the underlying disease. The liability of treatment should be considered in cases of HLH occurring in patients with advanced melanoma successfully treated with a combined targeted therapy. A rechallenge with a concurrent anti-BRAF/anti-MEK can be proposed in this setting.