Efficacy and safety of dabrafenib plus trametinib in BRAFV600E-mutated advanced thyroid carcinoma: Real world experience in 37 patients

This study aimed to investigate the clinical efficacy and safety of dabrafenib plus trametinib for BRAFV600E-mutated advanced thyroid carcinoma in a Japanese real-world setting. We analyzed 37 BRAFV600E-mutated advanced thyroid carcinoma patients treated with dabrafenib plus trametinib between November 2023 and July 2025. Thirty-one patients (84%) had papillary thyroid carcinoma (PTC) histology, one (3%) had poorly differentiated thyroid carcinoma (PDTC) histology, and 5 (13%) had anaplastic thyroid carcinoma (ATC) histology. Among 31 PTC patients, dabrafenib plus trametinib was initiated as first-line treatment in 16 patients. The most common previous systemic therapy was lenvatinib (n = 16, 43%). The most common sites of target lesion were the lung (n = 23, 62%) and lymph node (n = 23, 62%). The median sum of the diameters of the target lesion was 40 mm (range, 8-166 mm). The objective response and disease control rates were 29% and 74% in patients with PTC, and 50% and 83% in patients with non-PTC (PDTC and ATC), respectively. The 12-month progression-free survival rates in patients with PTC and non-PTC (PDTC and ATC) were 73.2% (95% confidence interval CI, 48.7-87.4%) and 60.0% (95% CI, 12.6-88.2%) (hazard ratio, 2.769; 95% CI, 0.691-11.1; p = 0.134), respectively. Dabrafenib plus trametinib treatment showed a response rate similar to that observed in clinical trials for BRAFV600E-mutated advanced thyroid carcinoma in this real-world study. However, long-term follow-up is required to determine the efficacy of dabrafenib plus trametinib treatment.