272 Use of LioCyx-M, autologous hepatitis B virus (HBV)-Specific T cell receptor (TCR) T-cells, in advanced HBV-related hepatocellular carcinoma (HCC)

Background We have demonstrated the ability of Hepatitis-B-virus (HBV)-specific T cell receptor (TCR) bioengineered T cells to recognize and lyse Hepatocellular carcinoma (HCC) cells expressing HBV antigens derived from HBV-DNA integration in patients with liver transplant.1 LioCyx-M is an immunotherapeutic product composing of autologous T cells transiently modified with in-vitro transcribed mRNA encoding HBV-specific TCR. The transient TCR expression makes LioCyx -M amenable to a dose escalating posology. Methods The primary endpoint of this phase 1 trial is to assess the safety and tolerability of LioCyx-M in patients with advanced HBV-HCC without curative treatment options. Eligible patients were diagnosed with Barcelona clinic liver cancer stage B or C HCC (Child-Pugh 1 year antiviral treatment prior to enrollment. These patients had matching HLA class I genotypes which present HBV encoded antigen. Peripheral blood was collected from each patient prior to each dose for LioCyx-M manufacturing. Patients received 4 escalating doses of 1×104 cells/kg, 1×105 cells/kg, 1×106 cells/kg, 5×106 cells/kg bodyweight (BW) in the first treatment cycle, each intravenously administered weekly. Patients underwent 1-month safety assessment post the 4th infusion, according to Common Terminology NCI CTCAE Version 4.0.3. If there were no dose associated toxicities, patients were eligible to continue administration of LioCyx-M at dose of 5 × 106 cells/kg BW weekly. Tumor response per RECIST 1.1 criteria and survival time were assessed. Results At data cutoff (30 April 2020), eight patients were enrolled, with a median age of 53 (range: 49 - 67). These patients received a median number of 6 (range: 4 - 12) infusions of LioCyx-M. 1 patient developed Grade 3 elevations in alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST) and bilirubin after receiving LioCyx-M at dose level of 1×105 cells/kg BW. Another patient had Grade 1 transient fever after receiving LioCyx-M at dose level 5×106 cells/kg BW in the 4th, 5th and 6th infusions. No treatment-related adverse events (trAEs) such as cytokine release syndrome or neurotoxicity were observed. No fatal trAEs were observed. The median time to progression was 1.9 months (range: 0.2 - 9.5 months). The median overall survival was 34 months (range: 3 - 38.2 months). Conclusions The encouraging clinical outcome and tolerable safety highlight the good benefit-risk profile of LioCyx-M. Therefore, further exploration of efficacy of LioCyx-M treatment for advanced HBV-HCC is warranted in a Phase 2 proof-of-concept clinical study. Acknowledgements Funding: Lion TCR. Trial Registration NCT03899415 Ethics Approval The study was approved by Fifth Medical Center of Chinese PLA General Hospital’s Ethics Board, approval number R2016185DI010. Reference Tan AT, Yang N, Lee Krishnamoorthy T, et al. Use of Expression Profiles of HBV-DNA Integrated Into Genomes of Hepatocellular Carcinoma Cells to Select T Cells for Immunotherapy. Gastroenterology 2019;156(6):1862–1876.e9.