Progressive locally advanced or metastatic radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) patients treated with donafenib: A real world study.

e18126 Background: Donafenib was approved for the treatment of RAI-R DTC patients by National Medical Products Administration (NMPA) in 2022, The main objectives of this study were to assess real-world clinical effectiveness and safety in RAI-R DTC patients treated with donafenib at Fudan University Shanghai Cancer Center. Methods: An observational patient chart review was conducted. The study cohort comprised RAI-R DTC patients who was treated with donafenib monotherapy (200 mg, bid), between Janunary 1, 2023 and December 16, 2024. Data were collected by prescribing physicians from individual patients’ electronic health records and were de-identified before filling into an electronic case report form. The primary endpoint was objective response rate (ORR), and the secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate (DCR), etc. Time to event endpoints were assessed using Kaplan-Meier methods. Results: Of the 15 patients reviewed, 66.7% were female and Patients’ median age was 58 years at donafenib initiation; 86.7% had ECOG performance status = 1, 80% of patients had stage IVb disease (other 3 patients were in stage II because of age under 50) and 93.3% of patients had lung metastases. The median follow-up time was 20 months [1.6-23.5], Provider-reported best overall response over the course of donafenib treatment was: partial in 20%, stable in 60%,with an ORR of 20% and DCR of 80%. Median PFS and Median OS were not reached. The estimated 12-month PFS rate was 72.7% (95% CI, 49.7%, 1) and Estimated 12-month OS rate was 84.6% (95% CI, 67.1%, 1). Median serum Tg dropped from baseline rapidly in the first 3 weeks, Early in cycle two, biochemical response was observed in 85.7% of patients. ≥ Grade 3 TRAEs were observed in 5/15 (33.3%) of patients, the most frequent TRAE was hand foot skin reaction (all grades, 66.7%). There were no treatment-related deaths. Conclusions: The current study enriched the efficacy and safety data of donafenib in the treatment of RAI-R DTC patients in real-world clinical practice in China, which enrolled more patients with PS ≥ 1, Follicular DTC, and transferring more widely compared with the phase III DIRECTION study. In addition, the efficacy and safety results are consistent with DIRECTION study.