CIO 2022-33 Atezolizumab + Bevacizumab vs Sorafenib in HCC Patients With Prior Locoregional Therapy: IMbrave150 Exploratory Data

Winner of 2022 Best Poster Award

Purpose: Atezolizumab (atezo) + bevacizumab (bev) has been approved in > 80 countries for systemic treatment (tx)–naive patients (pts) with unresectable HCC, based on IMbrave150 (NCT03434379; Finn RS NEJM 2020). Here, we report post hoc exploratory results of atezo + bev vs sorafenib (sor) in pts who had prior LRT using updated IMbrave150 data with 12 mo of further follow-up from primary analysis (Finn RS ASCO GI 2021).

Methods: Pts were randomized 2:1 to atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w or sor 400 mg bid until unacceptable toxicity or loss of clinical benefit per investigator. IMbrave150 enrolled 501 systemic tx–naive pts with unresectable HCC, ≥ 1 measurable untreated lesion (RECIST 1.1), Child-Pugh class A liver function and ECOG PS ≤1, including pts with prior LRT.

Results: 175, 84 and 77 atezo + bev pts and 80, 44 and 41 sor pts had 0, 1-2 and ≥ 3 prior lines of LRT, respectively. Compared with sor pts, atezo + bev pts had median overall survival (mOS) of 19.4 vs 13.1 mo (HR, 0.61; 95% CI: 0.44, 0.86) in pts without prior LRT, 22.8 vs 10.2 mo (HR, 0.60; 95% CI: 0.36, 1.00) in pts with 1-2 LRTs and 17.4 vs 16.6 mo (HR, 0.83; 95% CI: 0.51, 1.37) in pts with ≥ 3 LRTs. See table for more efficacy data. Grade 3-4 treatment-related adverse events were seen in 79 (46%), 33 (39%) and 31 (41%) atezo + bev pts and 30 (39%), 20 (49%) and 22 (58%) sor pts who had 0, 1-2 and ≥ 3 LRTs, respectively.

Conclusions: Survival benefit with atezo + bev over sor was seen in pts regardless of the number of prior LRTs. Atezo + bev seemed to have more benefit in pts with 1-2 vs ≥ 3 prior LRTs, suggesting an optimal time for switching from LRT to systemic tx.