Clinicogenomic Features and Targetable Mutations in NSCLCs Harboring BRAF Non-V600E Mutations: A Multi-Institutional Genomic Screening Study (LC-SCRUM-Asia)

BRAF non-V600E mutations occur in 1% to 2% of NSCLCs. Because of their rarity, the clinical backgrounds and outcomes of cytotoxic chemotherapy or immunotherapy remain unclear, and no targeted therapies are approved for BRAF non-V600E-mutant NSCLC.In this multi-institutional prospective lung cancer genomic screening project (LC-SCRUM-Asia), we evaluated the clinicogenomic characteristics and therapeutic outcomes of BRAF non-V600E-mutant NSCLC.From March 2015 to November 2021, a total of 11,929 patients with NSCLC were enrolled. BRAF mutations were detected in 380 (3.5%), including the V600E (class I) in 119 (31%) and non-V600E in 261; the non-V600E were functionally classified into class II (122, 32%), class III (86, 23%), and non-classes I to III. Smokers and having concurrent RAS gene family or TP53 mutations were more frequently associated with class II or III than with class I. In patients with class III as compared with class I, the progression-free survival in response to platinum-containing chemotherapies (median, 5.3 versus 11.5 mo, p < 0.01) and the overall survival (median, 14.5 versus 34.8 mo, p < 0.02) were significantly shorter. Furthermore, class IIa mutations were significantly more frequent in our Asian cohort than in previously reported cohorts. The clinicogenomic features associated with class IIa were similar to those associated with class I, and one patient with NSCLC with K601E had a good response to dabrafenib plus trametinib.Patients with NSCLCs with BRAF non-V600E, especially class III, were associated with poorer therapeutic outcomes than those with V600E. Furthermore, patients with NSCLC with class IIa had distinct clinicogenomic features, and further preclinical and clinical studies are needed to evaluate class IIa mutations as a therapeutic target.