Comparative effectiveness of two first-line, ICI-based regimens for advanced HCC: a target trial emulation using an electronic medical record network.

Introduction: Head-to-head comparative evidence of the relative efficacies of atezolizumab plus bevacizumab (Atezo+Bev) and tremelimumab plus durvalumab (Treme+Dur) as first-line therapies for advanced hepatocellular carcinoma (HCC) remains limited. Thus, in the present study, we compared the real-world efficacy and safety of these two modalities using a target trial emulation approach. Methods: Using the TriNetX Research Network, we identified adults (≥20 years) with HCC (ICD-10 C22.0) who initiated first-line Atezo+Bev or Treme+Dur (November 2022- November 2024). Propensity score matching (1:1) was used to balance the baseline characteristics. The primary outcome measure was overall survival (OS). Secondary outcomes included 1- or 2-year OS and organ-specific immune-related adverse events (irAEs) within 12 months, based on pre-specified ICD-10 definitions. Results: After matching, 640 patients were included in each group. Residual imbalance persisted in hepatic reserve markers (albumin, international normalized ratio, and platelet count; standardized mean differences >0.1). One-year OS was numerically higher in the Atezo+Bev group than in the Treme+Dur group (61% Conclusions: In this real-world target trial emulation, Atezo+Bev and Treme+Dur demonstrated broadly comparable long-term OS rates when used as first-line therapies for HCC. While baseline hepatic reserve plays an important role, the treatment regimen itself may contribute to earlier onset of hepatic and respiratory irAE. Careful monitoring for early-onset hepatic dysfunction and respiratory irAEs may be warranted in patients treated with Treme+Dur combination therapy.