Immunotherapy Benefit in a Patient With Non-Small Cell Lung Cancer and a Rare BRAF Mutation.

Immunotherapy is less effective in non-small cell lung cancer (NSCLC) with driver mutations in epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) and some may extrapolate this trend to other driver mutations. Up to 4% of NSCLC cases contain a BRAF mutation. Most BRAF mutations are V600E, and little is known about the impact of treatment in rare BRAF G469A mutations. We present a case of a patient found to have BRAF G469A mutated NSCLC. She was diagnosed with Stage IIIB NSCLC and treated with concurrent chemotherapy and radiation. Post-treatment imaging demonstrated disease progression and she was started on nivolumab, resulting in a dramatic and prolonged response which is ongoing after 76 cycles. Her substantial response and prolonged benefit suggest that BRAF-mutated NSCLC may respond better than EGFR- or ALK-driven disease to immunotherapy. Due to the rarity of specific mutations, this case adds to the limited current published literature on NSCLC harbouring a BRAF G469A mutation and suggests that immunotherapy is a reasonable treatment option.