Risk of proteinuria with atezolizumab plus bevacizumab versus lenvatinib in first-line systemic treatment for hepatocellular carcinoma.

558 Background: Proteinuria presents a challenging complication during systemic therapy for hepatocellular carcinoma (HCC). This study aims to identify risk factors for proteinuria in patients with HCC treated with atezolizumab plus bevacizumab (Atezo/Bev) or lenvatinib (LEN) as first-line systemic treatment. Methods: A retrospective analysis was conducted on 622 consecutive patients with unresectable HCC who received Atezo/Bev or LEN as first-line systemic treatment between October 2013 and October 2022. Cumulative incidence of proteinuria was estimated using Kaplan–Meier curves and compared using log-rank tests. Risk factors for proteinuria were identified using Cox proportional-hazard models, along with propensity score-matched and subgroup analyses. Results: Among 367 patients treated with Atezo/Bev and 255 with LEN, the cumulative incidence of proteinuria at 12 months was 27.5%. In the multivariable analysis, Atezo/Bev treatment (HR, 1.57; 95% CI, 1.03–2.42), diabetes (HR, 1.64; 95% CI, 1.03–2.61), Child–Pugh class B (HR, 3.43; 95% CI, 1.34–8.78), macrovascular invasion (MVI; HR, 1.58; 95% CI, 1.04–2.38), and an estimated glomerular filtration rate ≤60 mL/min/1.73 m 2 (HR, 3.21; 95% CI, 1.84–5.62) were identified as risk factors for proteinuria. A higher risk of proteinuria in Atezo/Bev patients compared with LEN was consistently observed in the PS-matched cohort, particularly pronounced in subgroups with MVI (HR, 2.84; 95% CI, 1.23–6.54) compared with those without MVI (HR, 1.31; 95% CI, 0.69–2.47). Conclusions: Patients treated with Atezo/Bev as first-line systemic treatmentfor HCC exhibited a higher risk of proteinuria compared with those with LEN, particularly when accompanied by MVI.