Increased fibroblast activation protein expression is positively correlated with the dedifferentiation and aggressiveness of thyroid cancer. Radiolabeled fibroblast activation protein inhibitor therapy, also known as radioligand therapy has become a novel treatment for patients with radioactive iodine refractory thyroid cancer and disease progression after first-line treatment. However, a major problem in the therapeutic use of 177Lu-DOTA-FAPI has been its short half-life and fast rate of clearance. This study was designed to compare the efficacy of various doses of a long-lasting radiolabeled fibroblast activation protein inhibitor 177Lu-DOTA-EB-FAPI in patients with radioactive iodine refractory thyroid cancer.
This is an open-label, non-control, non-randomized study to investigate the long-lasting radiolabeled fibroblast activation protein inhibitor based radioligand therapy and evaluate response to 177Lu-DOTA-EB-FAPI in patients with radioactive iodine refractory thyroid cancer. A maximum of 3 cycles of various doses with 1.85-2.22GBq (50-60 mCi), 3.33-3.7GBq (90-100mCi), and 4.44-4.81GBq (120-130mCi) of 177Lu-DOTA-EB-FAPI will be injected intravenously separately. All patients will undergo 68Ga-FAPI-46 and 18F-FDG PET/CT scans before and after the treatment.