TVGN-489: A novel approach for the production of SARS-CoV-2-specific cytotoxic T lymphocytes to treat COVID-19

Abstract SARS-COV-2 (COVID-19) has resulted in over 2 million deaths. While vaccination is expected to decrease mortality, there remains a need for curative therapies for active infections. Uncertainties regarding the duration of post-vaccination immunity and the rapidity of mutational evolution by this virus suggest that it is unwise to rely on preventative measures alone. Dysregulation of endogenous cellular immunity has been implicated in the failure to control COVID-19 infections suggesting that allogeneic T cell therapy using nature’s curative approach to viral infections could successfully be applied to vulnerable patients. Allogeneic virus-specific cytotoxic T lymphocytes (CTLs) have a long track record of safety and efficacy in treating viral infections occurring after allogeneic stem cell transplantation. We hypothesize that this approach can be applied to the treatment of Covid-19. Covid-19 specific CTLs were produced by priming and enriching T cells from convalescent patients using COVID-19 peptides predicted or demonstrated to bind to specific HLA alleles. Utilizing the globally common HLA-A*02:01 allele as the restriction element, 7 peptides from 4 COVID-19 gene/ORF products were identified and used as a pool for serial restimulation and enrichment on a peptide pulsed, HLA-A*02:01 antigen presenting cell monolayer. This preclinical effort produced CTLs of high purity (>95% CD3+/CD8+, >60% positive by tetramer staining) and potency (60% lysis of peptide pulsed targets at an effector to target ratio of 3:1) in sufficient quantities for clinical application. Trials using these TVGN-489 CTLs and those produced with other SARS-COV-2 peptides and HLA restriction elements will hopefully be launched shortly.