Efficacy and safety of envafolimab plus lenvatinib combined with TACE in unresectable hepatocellular carcinoma: An open-label, single-arm, phase 2 study-The CISLD-12 study.

558 Background: Transarterial chemoembolization (TACE) is one of the standard treatments for patients with intermediate-stage hepatocellular carcinoma (HCC). The combination of immune checkpoint inhibitors (ICIs) and lenvatinib has shown to be an effective regimen in patients with unresectable HCC (uHCC). In this study, we aim to investigate the efficacy and safety of combination of Envafolimab (a novel, single-domain PD-L1 antibody) with Lenvatinib plus TACE in uHCC patients. Methods: This is a prospective, open-label, single-arm, phase 2 study. Adults with confirmed uHCC with BCLC stage B or C, Eastern Cooperative Oncology Group performance status 0 or 1, Child–Pugh scored ≤7 and no previous systemic treatment for HCC are eligible. Patients will receive Lenvatinib once daily plus Envafolimab every 3 weeks plus TACE. TACE will be conducted repeatedly every 6 weeks on demand according to investigators’ consideration, mainly based on the proportion of viable tumors. Imaging evaluation will be conducted every 6 weeks. The primary endpoint is objective response rate (ORR). Disease control rate (DCR), duration of response (DoR), progression free survival (PFS), overall survival (OS) and safety are evaluated as secondary endpoints (NCT05213221). Results: forty patients were consecutively enrolled from March, 2022 to September 2022. The median age was 54.5 years. At present, thirty-six patients were included for efficacy analysis, and forty for safety evaluation. Number of patients with BCLC stage B and C was 17(47.2%) and 19 (52.8%), respectively. 13 (36.1%) patients presented with portal vein tumor thrombus (PVTT) and 2 (5.6%) patient presented with hepatic vein tumor thrombus (HVTT). The ORR was 36.1% and 80.6%, and DCR was 77.8% and 83.3%, based on RECIST v1.1 and modified RECIST respectively. 11 patients reached the standard of conversion to resectable HCC and received radical resection. The most common TRAEs were elevated AST (75%), elevated ALT (65%) and leukopenia (42.5%). No treatment-related deaths occurred. The survival data are not mature at present. Conclusions: Envafolimab plus Lenvatinib combined with TACE is a promising and tolerable therapeutic regimen for patients with BCLC B/C unresectable HCC. Clinical trial information: NCT05213221 .