Cabozantinib Effective as Salvage Therapy in Thyroid Cancer

Patients with radioiodine (RAI)-refractory differentiated thyroid cancer (DTC) may experience significant clinical benefit if treated with cabozantinib in the salvage setting, according to a study published in the Journal of Clinical Oncology.¹

There is a lack of secondary therapies available for patients with thyroid cancer, and available therapies in second/third-line or salvage setting possess poor toxicity profiles or are inadequately able to sustain response to treatment. A previous phase 1 study demonstrated that cabozantinib may have potential for patients with DTC who have failed previous vascular endothelial growth factor receptor (VEGFR)-targeted treatment.

The researchers for this phase 2 study (ClinicalTrials.gov Identifier: NCT01811212) administered oral cabozantinib 60 mg once daily to 25 eligible patients with DTC. Twenty-one patients had failed one line of VEGFR-targeted therapy, and 4 patients had failed two lines. 

Ten (40%) of the 25 study patients had a partial response (PR), and 13 (52%) patients had stable disease (SD). The median time to achieve PR was 2 months, and median duration of PR was 11.3 months (95% CI, 10.3-not evaluable).

The median duration of follow-up was 22.8 months (95% CI, 21.2-30.2), at which point the median progression-free survival was 12.7 months (95% CI, 10.9-34.7). The median overall survival (OS) was 34.7 months (95% CI, 18.3-not reached).

One patient died due to treatment-related causes. The most frequently reported adverse events were weight loss, fatigue, diarrhea, hypertension, and palmar-plantar erythrodysesthesia.

Reference

1. Cabanillas ME, de Souza JA, Geyer S, et al. Cabozantinib as salvage therapy for patients with tyrosine kinase inhibitor-refractory differentiated thyroid cancer: results of a multicenter phase II international thyroid oncology group trial. J Clin Oncol. 2017 Aug 17. doi: 10.1200/JCO.2017.73.0226. [Epub ahead of print]