A presurgical combination therapy including pembrolizumab plus dabrafenib and trametinib significantly improved survival in patients with rare BRAF V600E–mutated anaplastic thyroid cancer compared with historical controls, according to new research from The University of Texas MD Anderson Cancer Center. The study findings were presented at the 2025 ASCO Annual Meeting (Abstract 6008).
Results from the phase II single-arm multicenter trial revealed that adding the immunotherapy drug to the targeted therapies enabled tumor resection in the majority of patients (74%), compared with 5% historically. Experts also found that the combination given before surgery increased overall survival from an average of 13 to 21 months.
“Anaplastic thyroid cancer is one of the most aggressive cancers, and patients often come in with tumors that can’t be surgically removed,” said presenter and lead investigator Mark Zafereo, MD, Professor of Head and Neck Surgery at the University of Texas MD Anderson Cancer Center. “In previous studies, standard treatment only gave patients a few extra months, but, by adding pembrolizumab, we’ve seen signs that we can control the cancer locally without needing a more radical surgical approach.”
Dabrafenib and trametinib are targeted therapies designed to block both the mutant BRAF protein and related proteins that become activated in BRAF-mutated cancers. This combination has been approved to treat multiple types of cancer with BRAF mutations, including anaplastic thyroid cancer, but patients ultimately develop resistance.
Between September 2021 and January 2025, this study enrolled 42 patients with BRAF V600E–mutated anaplastic thyroid cancer, 36 of whom are included in the current analysis. Patients received a median of four cycles of dabrafenib and trametinib before surgery, and 30 underwent surgery to have their tumors removed. Researchers found that the combination therapy increased progression-free survival from an average of 6.7 months to more than 1 year.
“This treatment plan has shown that not only are more patients able to undergo surgery, but they’re also living longer without their cancer coming back,” Dr. Zafereo said. “Based on our results, this approach should now be considered a standard of care for patients with this rare cancer that have this specific gene mutation.”
Side effects noted during the study included kidney injury, sepsis, and a tear near the small intestine after surgery. Limitations of the study may include the small sample size, the lack of a control arm, and a short follow-up for some patients.
Disclosure: This study was funded by Merck (known as MSD outside the United States and Canada) and Gateway for Cancer Research. For full disclosures of the study authors, visit coi.asco.org.
