Stereotactic body radiation therapy combined with atezolizumab and bevacizumab for hepatocellular carcinoma with extrahepatic metastasis: Preliminary result of a single-arm study.

Abstract

e16205 Background: IMbrave150 study confirmed the clinical benefit of atezolizumab and bevacizumab in patients with advanced hepatocellular carcinoma (HCC). However, patients with extrahepatic metastasis (EHS) had a poorer prognosis. Studies suggested “abscopal effect” of synchronous radiotherapy and immunotherapy may improve antitumor activity. This study aimed to evaluate efficacy and safety of stereotactic body radiation therapy (SBRT) combined with atezolizumab and bevacizumab in HCC patients with EHS. Methods: This single-arm study included HCC patients with EHS from January 2022 to November 2023 in Fudan University Shanghai Cancer Center. Prior tyrosine kinase inhibitor and/or immune checkpoint inhibitor treatment were eligible. After first dose atezolizumab and bevacizumab, SBRT was performed with a total dose of 25-50 Gy. The primary endpoint was objective response rate (ORR). The secondary endpoints included overall survival (OS), disease control rate (DCR), progression-free survival (PFS), time to progression (TTP), and duration of response (DOR). Results: Thirty-nine patients were included. Fourteen patients were treated as first-line therapy and 25 patients were treated as later-line therapy. The mean age was 56.69±11.21 years and 89.7% were male. Of these patients, 66.7% had hepatitis viral infection and 25.6% had vascular invasion. 53.8% of patients had ≥2 extrahepatic spread lesions. In addition, 33.3% of patients had received prior immunotherapy and 23.1% of patients had received tyrosine kinase inhibitor therapy. The median follow-up was 6.50 (range: 1.43-22.17) months. The ORR and DCR were 43.6% and 92.3%, respectively. The ORR was 57.1% and 36.0% in first-line subgroup and later-line subgroup, respectively. The 12-month OS rates was 54.7%. The median PFS, median TTP and median DOR were 6.73 months, 8.67 months, and 7.17 months, respectively. The incidence of all grade TRAE and grade ≥3 TRAE were 38.5% and 12.8%, respectively. The most common grade ≥3 TRAEs were decreased platelet count (7.7%), decreased white blood cell count (2.6%), pruritus (2.6%) and rectal bleeding (2.6%). No serious adverse events occurred. Conclusions: SBRT combined with systemic atezolizumab and bevacizumab showed encouraging efficacy with manageable safety profile for HCC patients with EHS regardless of prior treatment. Further studies are warranted. Clinical trial information: NCT05396937 . [Table: see text]