Supplementary Material for: Matching-adjusted Indirect Comparison of Arterial FOLFOX and Atezolizumab-Bevacizumab in Unresectable Hepatocellular Carcinoma

Introduction: Previous phase 3 FOHAIC-1 study demonstrated that hepatic arterial infusion chemotherapy (HAIC) of FOLFOX regimen displayed favorable outcomes in advanced hepatocellular carcinoma (HCC) patients, including those with high-risk features (main portal tumor invasion and > 50% liver infiltration). This study aimed to compare the treatment efficacy of HAIC-FOLFOX versus atezolizumab-bevacizumab in HCC patients. Methods: Individual patient data from the Chinese FOHAIC-1 study and aggregate data from the global IMbrave150 study were used to conduct an anchored matching-adjusted indirect comparison (MAIC). Hazard ratios (HR) and restricted mean survival times (RMST) were calculated to assess survival differences. Landmark analysis was performed to evaluate time-sensitive treatment effects, and simulated treatment comparison (STC) was conducted as sensitivity analysis. Rates of treatment-related adverse events (TRAEs) and TRAE-related discontinuations were also compared. Results: After matching baseline characteristics, HAIC showed a numerical OS benefit (HR 0.57, 95% CI, 0.30–1.08) and similar PFS benefit (HR 0.79, 95% CI, 0.43–1.47) compared to atezolizumab-bevacizumab in the overall population. In high-risk patients, HAIC demonstrated significantly improved OS (HR 0.30, 95% CI, 0.12–0.72) and 2.89-month longer RMST compared to atezolizumab-bevacizumab (95% CI, 0.15–5.64 months). Additionally, HAIC showed superior PFS (HR 0.25, 95% CI, 0.10–0.64) and 2.88-month longer RMST over atezolizumab-bevacizumab (95% CI, 0.90–4.86). Landmark analysis in high-risk group revealed that HAIC was associated with significant improvements in both OS (HR 0.32, 95% CI, 0.13–0.79) and PFS (HR 0.24, 95% CI, 0.09–0.63) during the 0–12 months following treatment initiation. Sensitivity analysis using the anchored STC analysis yielded consistent results. HAIC was associated with lower rates of grade 3-4 TRAEs and TRAE-related discontinuation in both the overall population and high-risk group. Conclusion: HAIC treatment provided superior survival benefits and a favorable safety profile compared to atezolizumab-bevacizumab in high-risk HCC patients.