The efficacy and safety of sequential use of anlotinib and 131I for locally advanced or metastatic differentiated thyroid cancer: A single-arm phase II clinical trial.

Abstract

e18102 Background: Locally advanced or metastatic differentiated thyroid cancer (DTC) commonly responds poorly to radioiodine (131I) treatment alone. Tyrosine kinase inhibitors, however, have exerted promising antitumor activity in multiple advanced solid tumors. This study aimed to investigate the efficacy and safety of sequential use of anlotinib and 131I for the treatment of locally advanced or metastatic DTC. Methods: This is a single-arm phase II open-label clinical trail. The key eligibility criteria included locally advanced or metastatic 131I-avid DTC, ECOG PS of 0-1, and at least one measurable lesion. Previous tyrosine kinase inhibitor was not allowed. Patients initially received anlotinib (12 mg QD, 2 weeks on/1 week off ) for 4 cycles. At the beginning of 13th week when levothyroxine had been discontinued for 4 weeks, diagnostic 131I whole body scan (Dx-WBS) was performed, and those with 131I-avid lesions were immediately identified to undergo 131I treatment. The primary endpoint was objective response rate (ORR) . The secondary endpoints included disease control rate (DCR), biochemical response rate (BRR), time-to-response (TTR), progression-free survival (PFS), and safety. Results: From June 2021 to December 2022, a total of 16 patients with locally advanced or metastatic DTC were included. At the data cut off, 8 patients (4 males and 4 females) were withdrawn from the trial due to negative Dx-WBS, and the remaining 8 patients were subsequently treated with 131I. Six patients who had completed at least one cycle of sequential treatment were eligible for data analysis. Partial response and stable disease were found in 2 (33.33%) and 3 (50%) patients, respectively. An ORR of 33.33% [95% CI, 4.33-77.72], a DCR of 83.33% [95% CI, 35.88-99.58], a BRR of 100% [95% CI, 54.07-100.00], and a TTR of 6.34 months [95% CI, 5.85-NE] were achieved. Median PFS was not reached. Grade 3 adverse events occurred in 2 (33.33%) of the 6 subjects, including pain owing to skeletal metastasis in one patient and drug-related hypertention in the other. Conclusions: This study firstly demonstrates the favorable efficacy and safety of sequential therapy with tyrosine kinase inhibitor and 131I, suggesting anlotinib as a adjuvant option for 131I treatment of locally advanced or metastatic DTC. Randomized controlled studies on sequential therapy versus 131I treatment are warranted. Clinical trial information: ChiCTR2100045178 .