Efficacy and safety of pembrolizumab monotherapy in patients with advanced thyroid cancer in the phase 2 KEYNOTE-158 study.

Pembrolizumab demonstrated manageable toxicity and durable antitumor activity in a small subset of patients with advanced thyroid cancer. These results provide evidence of modest antitumor activity in this setting regardless of tumor PD-L1 expression. Future studies evaluating immune checkpoint inhibitors in patients with differentiated thyroid cancer should focus on biomarker-driven patient selection or combination of immune checkpoint inhibitors with other agents, in order to achieve higher response rates than observed in this study.