Immune-mediated adverse events following atezolizumab and bevacizumab in a multinational Latin American cohort of unresectable hepatocellular carcinoma.

Aims: Latin America has been underrepresented in trials evaluating immunotherapy for hepatocellular carcinoma (HCC). We aimed to describe the incidence of immune-related adverse events (irAEs) and their impact on outcomes in a Latin American cohort.

Methods: A multicenter prospective study was conducted in Argentina, Brazil, Chile, and Colombia, including patients who received atezolizumab plus bevacizumab. A time-covarite proportional hazard analysis evaluated the effect of irAEs.

Results: 99 patients were included. The median treatment duration was 6 months, with a median survival of 17.0 months (95% CI: 12.6-19.8). The irAE incidence rate was 2.1 cases per 100 persons-months (cumulative incidence 18.1% (95% CI: 11.1-27.2%)). Median time to irAE was 2.3 months (range 1.4-4.8), most frequently hepatitis (n = 6), thyroiditis (n = 5), and 8/18 required steroids. Follow-up, treatment duration, and overall survival were similar regardless of the occurrence of irAEs (HR = 1.71, 95% CI: 0.76-3.86; P = 0.19). Baseline alpha-feto protein ≥400 ng/ml (HR: 2.9 (95% CI: 1.1-7.6)) was independently associated with irAE.

Conclusion: The incidence of irAEs in this cohort is lower than reported in controlled trials, withouut impact on survival outcomes. Education and early recognition are crucial to ensure that these events are identified and addressed.