Sintilimab plus bevacizumab combined with radiotherapy as first-line treatment for hepatocellular carcinoma with portal vein tumor thrombus: A multicenter, single-arm, phase 2 study.

Background and aims: Systemic treatments are listed as first-line therapies for HCC with portal vein tumor thrombus (PVTT), resulting in modest efficacy. We aimed to evaluate the efficacy and safety of sintilimab plus bevacizumab combined with radiotherapy in HCC with PVTT and to identify prognostic biomarkers.

Approach and results: This open-label, multicenter, single-arm, phase 2 clinical trial was conducted at 3 tertiary hospitals in China. A total of 46 patients with HCC with PVTT were enrolled. All the patients received the first cycle of i.v. sintilimab (200 mg, day 1) plus bevacizumab (15 mg/kg, day 1) within 3 days after enrollment. Radiotherapy (30-50 Gy/10 fractions) was administered after 2 cycles of Sin-Bev. Sin-Bev was disrupted during radiotherapy and resumed 2 weeks after radiotherapy and continued every 3 weeks thereafter until disease progression, unacceptable toxicity, or withdrawal of consent. The primary end point was objective response rate. Patients obtained an objective response rate of 58.7% and a disease control rate of 100%. After a median follow-up time of 26.0 months (95% CI: 24.0-26.0), the median OS was 24.0 months (95% CI: 19.0 to not applicable) and the median progression-free survival was 13.8 months (95% CI: 12.0-21.0), respectively. No unexpected adverse events or treatment-related deaths occurred. Mutations of PCTMD1 were predictive of shorter OS and progression-free survival.

Conclusions: Sintilimab plus bevacizumab combined with radiotherapy provides favorable treatment response and survival outcomes along with an acceptable safety profile in the first-line setting for patients with HCC with PVTT (ClinicalTrials.gov Identifier: NCT05010434).