Oncology ·
Short-course dabrafenib and trametinib restored iodine uptake in some patients
In a multicentre phase II trial of 14 patients with progressive metastatic radioiodine-refractory thyroid cancer, investigators assessed iodine uptake after dabrafenib plus trametinib. Nine patients met dosimetry criteria for radioiodine treatment, and uptake was restored within two weeks in six of them.
- Nine of 14 patients met criteria for radioiodine treatment.
- Six of nine treated patients restored uptake within two weeks.
- Objective response rate was 75% among radioiodine-treated patients.
- Small phase II study; findings need further validation.
MAPK pathway activation can reduce expression of iodine-handling genes and contribute to radioiodine resistance in thyroid cancer. This multicentre phase II trial enrolled 14 patients with progressive metastatic radioiodine-refractory thyroid carcinoma carrying a BRAFV600E or RAS mutation. Patients received dabrafenib and trametinib, with I-124 PET/CT dosimetry at baseline and after two weeks; imaging could be repeated at week four if treatment criteria were not met. The primary endpoint was predicted lesional absorbed dose of at least 20 Gy with an I-131 activity of no more than 300 mCi.
Nine of 14 patients (64%) met the dosimetry threshold and received radioiodine. Six of those nine (67%) had restored iodine uptake within two weeks. Among radioiodine-treated patients, the best objective response rate within six months was 75% by RECIST, and median progression-free survival was 10.8 months. RAS-mutant tumours showed greater lesion regression than BRAFV600E-mutant tumours.
The findings suggest that re-differentiation can occur rapidly in some patients and that treatment duration might be individualized. However, the study was small, and the reported response and survival outcomes were among patients who received radioiodine. The results do not establish a new standard of care; the abstract does not provide further safety details.
In practice
For patients with progressive metastatic radioiodine-refractory thyroid cancer carrying BRAFV600E or RAS mutations, short-course dabrafenib plus trametinib was followed by restored iodine uptake within two weeks in six of nine patients who ultimately met dosimetry criteria for radioiodine. This suggests that early dosimetry may help identify patients who can proceed to radioiodine without empirically prolonged inhibitor treatment. The evidence comes from a small phase II trial, and the response and progression-free survival results were reported among radioiodine-treated patients; these findings do not establish a practice-changing treatment approach.
AI-generated clinical interpretation · Not editor-reviewed
Is this summary clinically accurate?
Help fellow clinicians: your rating sends inaccurate summaries straight to our editors.
Sign in to rate this summary →Source
Clinical Cancer Research: Kinetics of Re-differentiation with Short-Course Dabrafenib and Trametinib in Patients with Radioiodine-Refractory Thyroid Cancer ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.