Background/Aim: The present study aimed to develop detailed parameters for prediction of prognosis for patients with unresectable hepatocellular carcinoma (uHCC) receiving Atezolizumab plus Bevacizumab (Atez/Bev). Methods: Between September 2020 and January 2023, the patients treated with Atez/Bev were enrolled (n=719, males 577, median age 74 years). Factors involved in overall survival (OS) were extracted and a prognostic scoring system based on hazard ratio (HR) was created. OS and progression-free survival (PFS) were examined retrospectively, and the prognostic ability of the newly system was compared to CRAFITY score using concordance index (c-index) and Akaike Information Criterion (AIC) results. Results: Cox-hazards multivariate analysis showed BCLC classification C/D (HR 1.4; 1 point), AFP ≥100 ng/mL (HR 1.4; 1 point), mALBI 2a (HR 1.7; 1 point), mALBI 2b/3 (HR 2.8; 2 points), and DCP ≥100 mAU/mL (HR 1.6; 1 point) as significant factors. The assigned points were added and used for IMnunotherapy with AFP, BCLC staging, mALBI, and DCP evaluation (IMABALI-De) scoring. For IMABALI-De scores of 0/1/2/3/4/5, OS was not applicable (NA)/NA/26.11/18.79/14.07/8.32 months (P<0.001; AIC 2788.67, c-index 0.699), while for CRAFITY scores of 0/1/2, OS was 26.11/20.29/11.32 months (p<0.001; AIC 2864.54, c-index 0.606). PFS for those IMABALI-De scores was 21.75/12.89/9.18/8.0/5.0/3.75 months (P<0.001; AIC 5203.32, c-index 0.623) and for the CRAFITY scores was10.32/7.68/3.57 months (p<0.001; AIC 5246.61, c-index 0.574). IMABALI-De score had better AIC and c-index results as compared to CRAFITY score for both OS and PFS. Conclusion: The proposed IMABALI-De score may have a favorable prognostic predictive ability for uHCC patients with Atez/Bev.
