Abstract
BACKGROUND: H101, an innovative oncolytic adenovirus, has shown potential in modifying the tumor microenvironment from immunologically 'cold' to 'hot'. When combined with nivolumab, a programmed cell death protein 1 inhibitor, this synergy may offer substantial therapeutic benefits beyond the capabilities of each agent alone. PATIENTS AND METHODS: In this pilot study, we assessed the efficacy and safety of combining H101 with nivolumab in advanced hepatocellular carcinoma (HCC) patients who failed prior systemic therapy. The participants received initial oncolytic virus (OV) pretreatment with intratumoral H101 injections (5.0 × 10(11) vp/0.5 ml/vial, two vials per lesion) on days 1 and 3. Combination therapy started on day 8, with H101 administered every 2 or 4 weeks and nivolumab (240 mg) injections every 2 weeks. Treatment continued up to 12 months or until disease progression, intolerable toxicity, consent withdrawal, or study conclusion. The primary endpoint was the objective response rate (ORR). RESULTS: Between March 2020 and March 2022, 18 of 21 screened patients were assessable, showing an ORR of 11.1% [two cases of partial response (PR) and five cases of stable disease], with extrahepatic injections often leading to favorable outcomes. The disease control rate stood at 38.9%, with a 6-month survival rate of 88.9%. Median progression-free survival was 2.69 months, and overall survival (OS) was 15.04 months. Common adverse events included low-grade fever (100%) and pain related to centesis (33.3%), and no grade 3/4 events were reported. Significantly, local H101 injection showed potential in reversing immune checkpoint inhibitor resistance, evidenced by over 2.5 years of extended OS in PR cases with low α-fetoprotein. Additionally, decreasing neutrophil-to-lymphocyte ratio during OV pretreatment may predict positive outcomes. CONCLUSIONS: This study demonstrates the potential efficacy of combining H101 with nivolumab in treating refractory advanced HCC, with well-tolerated toxicities.