Initial or salvage treatment with apatinib shows promise against radioiodine-refractory differentiated thyroid carcinoma.

Abstract

ObjectiveSorafenib and lenvatinib have been recommended as standard tyrosine kinase inhibitors (TKIs) for progressive radioiodine-refractory differentiated thyroid carcinoma (RR-DTC). However, their efficacy remains limited with unresolved drug resistance. Therefore, we conceived this open-label study based on real-world evidence to investigate the efficacy and safety of apatinib in patients with progressive RR-DTC.MethodsOff-label use of apatinib as either initial treatment or salvage treatment for sorafenib resistance was investigated. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included objective response rate (ORR), overall survival (OS), and safety.ResultsFor all 28 enrolled patients, the median PFS was 15.1 months, with an ORR of 69.6%. The median OS was not reached at the data cut-off. In detail, the median PFS of 17.3 months and the ORR of 75% were determined in patients with TKI-naive RR-DTC (initial treatment group, n = 14). And, in patients with first-line sorafenib-resistant RR-DTC (salvage treatment group, n = 14), a median PFS of 12.0 months was reached, with an ORR of 45.5%. In the salvage treatment group, the median OS from the start of apatinib administration was 20.6 months, reaching 89.1 months from sorafenib treatment initiation. Adverse events at grade 3 or higher occurred in 64.3% of all subjects treated with apatinib.ConclusionsThis study demonstrated that apatinib shows promise against RR-DTC with tolerable toxicity, representing a novel initial treatment for progressive RR-DTC and effective salvage treatment for RR-DTC resistant to sorafenib.