The efficacy and safety of anti-PD-1 antibody toripalimab combined with surufatinib in neoadjuvant treatment of locally advanced thyroid cancer: A phase II study.

6084 Background: Surgery is the primary treatment for locally advanced thyroid cancer. However, some locally advanced patients are not candidates for R0/1 resection. There is limited evidence of neoadjuvant treatment in locally advanced thyroid cancer. Surufatinib targets multiple kinases (VEGFR1-3, FGFR1 and CSF-1R) involved in tumor angiogenesis and tumor immune evasion. It is efficient, tolerable and safe for patients with radioiodine-refractory differentiated thyroid cancer to receive surufatinib. In addition, surufatinib plus toripalimab (an anti-PD-1 antibody) showed encouraging antitumor activity and an acceptable safety profile in advanced solid tumors. This study aimed to evaluate the efficacy and safety of surufatinib plus toripalimab in locally advanced thyroid cancer in the neoadjuvant setting. Methods: In this single-arm phase II study, patients with pathologically confirmed diagnosis of unresectable or borderline resectable differentiated thyroid cancer were eligible and received a combination of 250 mg surufatinib (oral, qd) with 240 mg toripalimab (IV, q3w). Treatment was continued until satisfied for curative surgery, disease progression, withdrawal of consent, unacceptable toxicity or investigator decision. Primary endpoint was objective response rate (ORR) by RECIST 1.1. Secondary endpoints included R0/1 resection rate, disease control rate (DCR), time to remission (TTR), adverse events (AEs), etc. Results: This study is ongoing. 10/10 patients were enrolled. 6 patients received ≥4 cycles of surufatinib plus toripalimab treatment and were also evaluated for efficacy. The ORR was 66.7% with 4 partial response (PR) and 2 stable disease (SD). 4 PR and 1 SD patients received R0 resections after neoadjuvant treatment. The safety was consistent with previously reported. No grade ≥3 AEs were observed. Specific AEs data are still being counted. Conclusions: Surufatinib in combination with toripalimab as neoadjuvant therapy for locally advanced thyroid cancer was feasible and majority of patients achieved R0 resection. AEs were mainly grade 1-2, and this combination was well-tolerated. The combination of these two agents should be further investigated for neoadjuvant treatment of locally advanced thyroid cancer based on good results. Clinical trial information: NCT04524884.