Genetically redirected HBV-specific T cells target HBsAg-positive hepatocytes and primary lesions in HBV-associated HCC.

ABSTRACT

Background and Aims: HBV-DNA integration in HBV-related hepatocellular carcinoma (HBV-HCC) can be targeted by HBV-specific T cells. SCG101 is an autologous, HBV-specific T-cell product expressing a T-cell receptor (TCR) after lentiviral transduction recognizing the envelope-derived peptide (S20-28) on HLA-A2. We here validated its safety and efficacy preclinically and applied it in an HBV-related HCC patient (NCT05339321). Methods: GMP-grade manufactured cells were assessed for off-target reactivity and functionality against hepatoma cells. Subsequently, a patient with advanced HBV-HCC (Child-PughA, BCLCB, ECOG0, HBeAg-, serum HBsAg+, hepatocytes 10% HBsAg+) received 7.9x107 cells/kg after lymphodepletion. Safety, T-cell persistence, and antiviral and antitumor efficacy were evaluated. Results: SCG101, produced at high numbers in a closed-bag system, showed HBV-specific functionality against HBV-hepatoma cells in vitro and in vivo. Clinically, treatment was well tolerated, and all adverse events, including transient hepatic damage, were reversible. On day 3, ALT levels increased to 1404 U/ml, and concurrently, serum HBsAg started decreasing by 3.84log and remained <1 IU/ml for over six months. HBsAg expressing hepatocytes in liver biopsies were undetectable after73 days. The patient achieved a partial response according to mRECIST score with a >70% reduction of target lesion size. Transferred T cells expanded, developed a stem cell-like memory phenotype, and were still detectable after six months in the patient's blood. Conclusions: SCG101 T-cell therapy showed encouraging efficacy and safety in pre-clinical models and in a patient with primary HBV-HCC and concomitant chronic hepatitis B with the capability to eliminate HBsAg+ cells and achieve sustained tumor control after single dosing.