Real-World Experience with Targeted Therapy for the Treatment of Anaplastic Thyroid Carcinoma.

BACKGROUND

Patients with anaplastic thyroid cancer (ATC) have a dismal prognosis, despite systemic cytotoxic chemotherapy. The objective of this study was to investigate the efficacy and safety of targeted therapy in ATC patients when used outside of a clinical trial.

METHODS

This is a retrospective review from April 2015 to May 2016 at a single academic institution where 16 ATC patients receiving targeted therapy outside of a clinical trial were studied. Ten patients (eight BRAF wild type and two BRAF mutant tumors) were started on lenvatinib, and six with BRAF-mutated tumors received a combination of dabrafenib plus trametinib. Best response evaluated by RECIST v1.1, progression-free survival, and overall survival were determined. Adverse events were evaluated for safety.

RESULTS

The majority of patients (63%) were men, and all had distant metastases or radiation-resistant primary disease at the time of treatment. In the entire cohort, 6/16 (38%) had a partial response, 6/16 (38%) had stable disease, and 2/16 (12%) had progressive disease. Two (12%) patients died before restaging. Median follow-up time was 11.8 months. Median progression-free survival was 3.7 months [confidence interval 1.8-7.6] in the entire cohort, 2.7 months for lenvatinib, and 5.2 months for dabrafenib plus trametinib. Median OS was 6.3 months [confidence interval 1.8-7.6] for the entire cohort, 3.9 months for lenvatinib, and 9.3 months for dabrafenib plus trametinib. Adverse events were as expected and manageable.

CONCLUSIONS

Targeted therapies, lenvatinib, and dabrafenib plus trametinib (for BRAF mutants) may provide clinical benefit in ATC patients who are unable to participate in clinical trials, and toxicities are manageable.