Does Anaplastic Thyroid Carcinoma Respond to PD-1 Blockade?
Posted: Wednesday, July 15, 2020
The PD-1 inhibitor spartalizumab may prove to be an effective treatment of anaplastic thyroid carcinoma, according to the early findings of a first-in-human study published in the Journal of Clinical Oncology. Matthew Taylor, MD, of the Oregon Health & Science University, Portland, and colleagues suggest additional studies are needed to understand checkpoint inhibition in this patient population.
“Spartalizumab demonstrated promising clinical activity and a good safety profile in a patient population with aggressive incurable disease and short life expectancy,” the authors concluded. “Targeting PD-1/PD-L1 may provide a much-needed treatment option for patients with PD-L1–positive advanced anaplastic thyroid carcinoma, including the BRAF wild-type population.”
A total of 42 patients with locally advanced and/or metastatic anaplastic thyroid carcinoma were enrolled in a phase II cohort of the study. The patients received 400 mg of spartalizumab intravenously once every 4 weeks. Using Response Evaluation Criteria in Solid Tumors, v1.1, the investigators reported an overall response rate of 19%. Three patients had a complete response, and five had a partial response. However, the highest rate of response was recorded in the subset of patients with PD-L1 expression ≥ 50% (6 of 17 patients; 35%).
The median progression-free survival was less than 2 months for PD-L1 subsets. However, 1-year progression-free survival rates increased in some patients with PD-L1–positive disease. For patients with PD-L1 expression between 1% and 49%, it was 20%, and for patients with PD-L1 expression of at least 50%, it was 29%. Overall survival also seemed to correlate with PD-L1 status, with median overall survival not yet reached in those with PD-L1–positive disease. Finally, in both patients with BRAF-nonmutant and BRAF-mutant disease, responses were durable, with a 1-year survival of 52.1% in the PD-L1–positive population.
Disclosure: The study authors’ disclosure information can be found at ascopubs.org.