# BRAF inhibitor or BRAF/MEK inhibitor treatment for patients with metastatic BRAF V600E mutated differentiated thyroid cancer

## TL;DR

This study shows that BRAF and MEK inhibitors can effectively treat advanced thyroid cancer in patients who do not respond to other treatments.

## Contribution

The study provides real-life evidence of the efficacy and tolerability of BRAF/MEK inhibitor treatment in metastatic BRAF V600E-mutated thyroid cancer.

## Key findings

- 70% of patients had an objective response to BRAF/MEK inhibitors.
- The 12-month overall survival rate was 90%.
- The treatment was well tolerated even as a second-line option.

## Abstract

The aim of this study is to demonstrate the real-life efficacy of BRAF and
MEK inhibitors in patients with advanced thyroid cancer.

This retrospective study evaluated the clinical efficacy of either a BRAF
inhibitor (dabrafenib) alone or a BRAF inhibitor (dabrafenib) in combination
with a MEK inhibitor (trametinib) in the treatment of 10 patients diagnosed
with metastatic BRAF-mutant RAI refractory thyroid cancer. The primary
endpoint was the investigator-assessed overall response rate (ORR).

The median patient age was 68 years, 60% were men, and all patients were
diagnosed with progressive BRAF V600E-mutant RAI-refractory papillary
thyroid carcinoma (PTC). In total, 70% of the patients had been previously
treated with multikinase inhibitors. One (1%) patient received a BRAF
inhibitor alone and 9 (90%) patients received a combination of BRAF and MEK
inhibitors. After treatment, 2 (20%) patients achieved a complete response,
5 (50%) patients achieved a partial response, 1 (10%) patient experienced
stable disease, and 1 (10%) patient experienced progressive disease. Seven
(70%) patients had an objective response rate (ORR) (complete or partial
response). Progression-free survival (PFS) was 70%, 40%, 30%, and 30% at 6,
12, 18, and 24 months, respectively. The 12-month overall survival (OS) rate
was 90%.

Dabrafenib in combination with trametinib was well tolerated and resulted in
substantial clinical benefit, with notable PFS and sustained OS, even as a
second-line treatment, in patients diagnosed with metastatic, progressive
BRAF V600E-mutated, RAI-refractory thyroid cancer.