Abstract
<b><i>Introduction:</i></b> Immunotherapy has resulted in pathologic responses in hepatocellular carcinoma (HCC), but the benefits and molecular mechanisms of neoadjuvant immune checkpoint blockade are largely unknown. <b><i>Methods:</i></b> In this study, we evaluated the efficacy and safety of preoperative nivolumab (anti-PD-1) in patients with intermediate and locally advanced HCC and determined the molecular markers for predicting treatment response. <b><i>Results:</i></b> Between July 2020 and November 2021, 20 treatment-naive HCC patients with intermediate and locally advanced tumors received preoperative nivolumab at 3 mg/kg for 3 cycles prior to surgical resection. Nineteen patients underwent surgical resection on trial. Seven (36.8%) of the 19 patients had major pathologic tumor necrosis (≥60%) in the post-nivolumab resection specimens, with 3 having almost complete (>90%) tumor necrosis. The tumor necrosis was hemorrhagic and often accompanied by increased or dense immune cell infiltrate at the border of the tumors. None of the patients developed major adverse reactions contradicting hepatectomy. RNA-sequencing analysis on both pre-nivolumab tumor biopsies and post-nivolumab resected specimens showed that, in cases with major pathologic necrosis, the proportion of CD8 T cells in the HCC tissues predominantly increased after treatment. Moreover, to investigate noninvasive biomarker for nivolumab response, we evaluated the copy number variation (CNV) using target-panel sequencing on plasma cell-free DNA of the patients and derived a CNV-based anti-PD-1 score. The score correlated with the extent of tumor necrosis and was validated in a Korean patient cohort with anti-PD-1 treatment. <b><i>Conclusion:</i></b> Neoadjuvant nivolumab demonstrated promising clinical activity in intermediate and locally advanced HCC patients. We also identified useful noninvasive biomarker predicting responsiveness.