Induced sarcoid-like reactions in patients with metastatic melanoma treated with dabrafenib and trametinib: a monocentric retrospective study

Combined BRAF and MEK inhibition is one of the first-line treatment strategies for patients with advanced BRAF-mutant melanoma. Sarcoid-like reactions (SLRs) have occasionally been described with melanoma systemic treatments such as immunotherapy or the BRAF inhibitor vemurafenib, but very few cases have been reported with dabrafenib and trametinib. Our aim was to better characterize SLR induced by this combination. We conducted a monocentric retrospective observational study among patients treated with dabrafenib and trametinib for BRAF-mutant advanced melanoma from January 2015 to March 2019. Patients presenting with histologically proven SLR were included. We also searched Medline database for all reported cases of SLR induced by targeted therapy. Of 63 patients on dabrafenib/trametinib combination, seven were diagnosed with a SLR. They all had specific cutaneous involvement, and one also displayed mediastinal and salivary glands involvement. None required systemic corticosteroids or dabrafenib/trametinib discontinuation. Three of them (43%) reached melanoma complete remission and are still on targeted therapy; and four patients progressed and died. A literature review yielded 22 additional cases of SLR induced by targeted therapy: the main affected organ was the skin, 11 patients (50%) had systemic involvement, five patients (23%) required systemic corticosteroids to reach partial or complete remission of SLR, 12 (55%) reached partial or complete response of melanoma while six (27%) progressed. BRAF and MEK inhibitors are potential triggers of SLR, although pathological mechanisms remain unclear. The mainstay of treatment is systemic or topical corticotherapy; targeted therapy discontinuation is usually not necessary.