Lenvatinib plus transarterial chemoembolization and PD-1 inhibitors as conversion therapies for unresectable intermediate-advanced hepatocellular carcinoma: a phase 2 trial and exploratory biomolecular study

Abstract Conversion therapy remains an uncommon strategy for managing unresectable hepatocellular carcinoma (uHCC) due to limited evidence supporting its efficacy. To address this gap, we initiated a prospective phase 2 multicenter trial (NCT04997850) comparing the LEN-TAP regimen, combining lenvatinib, transarterial chemoembolization (TACE), and PD-1 inhibitors, against TACE alone in uHCC patients. The study’s primary outcome was salvage liver resection (SLR) rate; secondary measures included objective response rate (ORR), overall survival (OS), event-free survival (EFS), recurrence-free survival (RFS), and safety profile. From October 2020 to November 2021, 142 eligible participants were assigned to LEN-TAP (n = 71) or TACE monotherapy (n = 71). At a median follow-up of 24.2 months, the LEN-TAP cohort exhibited a significantly higher SLR rate (59.2% vs. 18.3%, P < 0.001) and ORR (78.9% vs. 16.9%, P < 0.001). Median OS, EFS, and RFS were also substantially prolonged in the LEN-TAP cohort (not reached vs. 23.0 months, P < 0.001; 20.03 vs. 6.52 months, P < 0.001; 36.6 vs. 19.0 months, P = 0.048). Although grade 3 treatment-related AEs occurred more frequently with LEN-TAP (60.6% vs. 21.1%, P < 0.001), no grade 4 or higher toxicities were observed. Exploratory biomarker assessments via single-cell sequencing and flow cytometry linked elevated levels of circulating HLA-DR + CD38 + CD8 + T cells with improved treatment response. These T cells appear to mediate antitumor activity potentially through the CXCR6–PI3K–AKT signaling axis. In summary, the LEN-TAP protocol demonstrates promising efficacy and acceptable tolerability as a conversion therapy in uHCC, with peripheral HLA-DR + CD38 + CD8 + T cell abundance serving as a potential predictor of therapeutic benefit.