Camrelizumab and apatinib in Chinese patients with locally advanced or metastatic radioiodine-refractory differentiated thyroid cancer: an exploratory open-label, single-arm trial.

Abstract

Radioactive iodine-refractory differentiated thyroid cancer (RAIR-DTC) remains a therapeutic challenge, especially after progression on prior systemic therapies. While immune checkpoint inhibitors combined with antiangiogenic agents have shown synergy in other tumors, data in RAIR-DTC are limited. This study evaluated camrelizumab plus apatinib in first-line and salvage settings. This open-label, single-arm, phase II trial (NCT04560127) enrolled patients with locally advanced or metastatic RAIR-DTC. Patients received intravenous camrelizumab (200 mg every 2 weeks) and oral apatinib (250 mg daily) in 4-week cycle until progression or intolerable toxicity. The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR), overall survival (OS), disease control rate (DCR), and safety. Between September 2020 and August 2021, 20 patients were enrolled and treated. As of the data cutoff, the median follow-up was 28.4 months (IQR, 22.3-31.2). Median PFS was 11.0 months (95% CI, 6.0-14.2), with 11.6 months (95% CI, 4.8-NE) in treatment-naïve patients and 11.0 months (95% CI, 3.7-19.4) in pretreated patients. Median OS was not reached. The confirmed ORR was 30.0% (95% CI, 11.9-54.3), with 6 patients achieving partial response, and DCR was 95.0% (95% CI, 75.1-99.9). The most common grade ≥ 3 treatment-related adverse events were increased gamma-glutamyltransferase (40.0%) and increased alanine aminotransferase (30.0%). Camrelizumab plus apatinib demonstrated promising efficacy and manageable toxicity in RAIR-DTC across both first-line and salvage settings, supporting further evaluation as a potential second-line option in the absence of established standard therapies in this setting. The study was registered at clinicaltrials.gov with the identifier NCT04560127.