Abstract
IMPORTANCE: Patients with radioactive iodine-refractory differentiated thyroid cancer (RAIR-DTC) have a poor prognosis and limited treatment options. OBJECTIVE: To assess the efficacy and safety of apatinib, a highly selective vascular endothelial growth factor (VEGFR-2) inhibitor, in patients with progressive locally advanced or metastatic RAIR-DTC. DESIGN, SETTING, AND PARTICIPANTS: This randomized, double-blind, placebo-controlled, phase 3 trial (Efficacy of Apatinib in Radioactive Iodine-refractory Differentiated Thyroid Cancer [REALITY]) was conducted in 92 patients with progressive locally advanced or metastatic RAIR-DTC between February 17, 2017, and March 2, 2020, at 21 sites within China, and the data cutoff date for this analysis was March 25, 2020. INTERVENTIONS: Patients were randomly assigned (1:1) to apatinib, 500 mg/d, or placebo. Patients who developed progression while receiving placebo were allowed to cross over to apatinib. MAIN OUTCOMES AND MEASURES: The primary end point was investigator-assessed progression-free survival (PFS). Secondary end points included overall survival, objective response rate (ORR), disease control rate (DCR), duration of response, time to objective response, and safety. Intention-to-treat analyses were performed to evaluate efficacy. RESULTS: Of the 92 patients included in the trial, 56 were women (60.9%); mean (SD) age at baseline was 55.7 (10.6) years. Patients were randomized to the apatinib (n = 46) or placebo (n = 46) group. The median follow-up duration was 18.1 (IQR, 12.7-22.2) months. The median PFS was 22.2 (95% CI, 10.91-not reached) months for apatinib vs 4.5 (95% CI, 1.94-9.17) months for placebo (hazard ratio, 0.26; 95% CI, 0.14-0.47; P < .001). The confirmed ORR was 54.3% (95% CI, 39.0%-69.1%) and the DCR was 95.7% (95% CI, 85.2%-99.5%) in the apatinib group vs an ORR of 2.2% (95% CI, 0.1%-11.5%) and DCR of 58.7% (95% CI, 43.2%-73.0%) in the placebo group. The median overall survival was not reached for apatinib (95% CI, 26.25-not reached) and was 29.9 months (95% CI, 18.96-not reached) for placebo (hazard ratio, 0.42; 95% CI, 0.18-0.97; P = .04). The most common grade 3 or higher-level treatment-related adverse events in the apatinib group were hypertension (16 [34.8%]), hand-foot syndrome (8 [17.4%]), proteinuria (7 [15.2%]), and diarrhea (7 [15.2%])-none of which occurred in the placebo group. CONCLUSIONS AND RELEVANCE: The REALITY trial met its primary end point of PFS at the prespecified interim analysis. Apatinib showed significant clinical benefits in both prolonged PFS and overall survival with a manageable safety profile in patients with progressive locally advanced or metastatic RAIR-DTC. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03048877.