Complete radiological response to first-line regorafenib in a patient with abdominal relapse of BRAF V600E mutated GIST

Up to 13% of KIT and PDGFRA wild-type (WT) gastrointestinal stromal tumours (GIST) harbour a BRAF mutation, mostly involving the exon 15 V600E hot spot. Even if BRAF mutation is recognized as druggable target in other solid tumours, currently advanced BRAF-mutant GIST share the same therapeutical algorithm of KIT/PDGFRA mutants. We report a complete radiological response in a 51-year-old woman with V600E BRAF-mutated metastatic GIST who was treated with regorafenib (REG) as first-line therapy. REG represents the standard third-line therapy for advanced GIST patients progressing on or failing to respond to imatinib and sunitinib. However, according to its wide spectrum of action, with MAPK signalling pathway blockade at different levels, metastatic KIT/PDGFRA WT, including BRAF mutants, may benefit from REG upfront in first line.