952P Efficacy and safety of a PRospective, Observational trial of Lenvatinib cOmbined with transarterial chemoembolization (TACE) as initial treatment for advaNced staGe hepatocellular carcinoma (PROLONG): A multicenter, single-armed, real-world study

Transarterial chemoembolization (TACE) in combination with lenvatinib has been reported in several exploratory clinical studies in Chinese patients with hepatocellular carcinoma (HCC). Studies have showed good tumor response and survival benefit for combination therapy based on TACE plus lenvatinib in patients with advanced HCC. A multicenter, real-world study was conducted to explore the efficacy and safety of TACE in combination with lenvatinib as initial treatment for unresectable HCC patients in a real-world setting (PROLONG study, NCT04560751). This real-world study was conducted at 7 centers in China. Eligible patients were aged more than 18 years old, with HCC, CNLC stage IIb-IIIb with unresectable diseases, Child-Pugh ≤7, Eastern Cooperative Oncology Group (ECOG) performance status 0-1, no prior systemic therapy. All patients received TACE combined with lenvatinib, with or without immune checkpoint inhibitors. The primary endpoint was objective response rate (ORR), which was evaluated according to mRECIST, and secondary endpoints included organ-specific objective response rate, progression-free survival (PFS), AFP response rate and time to progression (TTP). A total of 197 patients were enrolled from August 2020 to February 2023, with 145 patients evaluable for efficacy. The ORR was 48.3% evaluated according to mRECIST, with a complete response (CR) rate of 8.3%, partial response (PR) rate of 40%. The disease control rate (DCR) was 86.2%. The median PFS was 10.2 months (95%CI, 5.9-14.5), and the median OS has not been reached. The most common adverse events (AE) were fever, elevated transaminases, and decreased platelets. No treatment-related grade 5 AE occurred. Combination therapy based on TACE plus lenvatinib in patients with unresectable hepatocellular carcinoma showed promising efficacy in the real-world setting. No unexpected adverse events were observed.