# Effective Treatment of Lung Adenocarcinoma With a Novel SLC44A1-BRAF Fusion Using Pembrolizumab Followed by Trametinib: A Case Report

## TL;DR

A 75-year-old woman with lung adenocarcinoma responded to treatment with pembrolizumab and trametinib after a rare SLC44A1-BRAF fusion was identified.

## Contribution

Reports a novel SLC44A1-BRAF fusion in lung cancer and its effective treatment with MEK inhibition.

## Key findings

- SLC44A1-BRAF fusion was identified in a lung adenocarcinoma patient.
- Trametinib controlled tumor progression after disease progression on pembrolizumab and docetaxel.
- The case highlights potential treatment strategies for rare BRAF fusion-positive NSCLC.

## Abstract

The serine-threonine protein kinase B-RAF (BRAF) fusions are rarely observed in non-small cell lung cancer (NSCLC) accounting for less than 1%, and therapeutic evidence for molecular-targeted drugs is lacking, unlike for BRAF V600E mutation by RAF and MEK inhibitors. A 75-year-old female patient with no smoking history and mild renal dysfunction developed recurrent lung adenocarcinoma and was initially treated with pembrolizumab immunotherapy followed by chemotherapy using docetaxel showing a certain efficacy but the disease finally progressed. Comprehensive genome profiling showed a novel SLC44A1-BRAF fusion and the tumor progression was controlled with the MEK inhibitor trametinib. Because of the rarity of NSCLC with BRAF fusion, the description of this case would be helpful for the treatment strategy for such tumors.