CD19 chimeric antigen receptor (CAR) engineered epstein-barr virus (EBV) specific T cells – an off-the-shelf, allogeneic CAR T-cell immunotherapy platform

Background & Aim Chimeric antigen receptor (CAR) T cells have demonstrated potent antitumor efficacy in treating a range of B-cell malignancies, yet technical and commercial challenges using an autologous approach hinder widespread development. Virus-specific T cells present a potential strategy towards an off-the-shelf, allogeneic platform due to the volume of supporting clinical data and additional advantages associated with native TCR engagement to latent virus antigens. Tabelecleucel (tab-cel®) is an investigational off-the-shelf, allogeneic T-cell immunotherapy utilizing native TCR specificity against Epstein-Barr virus (EBV) antigens present in lymphomas and other cancers. With low incidence of GvHD and no cytokine release syndrome, tab-cel® has been shown to be efficacious and well tolerated. Transfer of CAR transgenes into EBV-specific T cells represents an attractive approach to generate off-the-shelf, allogeneic CAR T therapies. Methods, Results & Conclusion We have generated EBV-specific T cells engineered with second generation CD19 CARs as tool compositions to evaluate the potential of this off-the-shelf CAR T approach. Allo-EBV.CD19.CAR T cells express high levels of CD19 CAR and maintain native EBV TCR expression. Allo-EBV.CD19 CAR T cells are predominantly central memory and show CD25, 4-1BB, and IFN-γ activation markers. Functional studies also demonstrate potent antitumor activity against CD19-positive NALM/6 and Raji tumor targets, but no activity against CD19-negative K562 cells. Allo-EBV.CD19.CAR T cells exhibit rapid and comparable killing kinetics compared to CD19.CAR T cells. Allo-CAR T cells also demosntarted antigen-specific proliferation against EBV and CD19-positive targets. Like unmodified EBV-specific T cells, allo.EBV.CD19.CAR T cells maintain the ability to kill B-lymphoblastoid cell lines (BLCL) and little reactivity or inflammatory cytokine secretion in response to HLA mismatched and antigen-negative targets. CD19 CAR engineered EBV T cells demonstrate efficient and potent killing of antigen-positive target cells, while exhibiting little alloreactivity. This platform provides a framework from which we are developing ATA3219, a next generation off-the-shelf, CD19-targeted CAR T utilizing a novel optimized stimulatory domain. Chimeric antigen receptor (CAR) T cells have demonstrated potent antitumor efficacy in treating a range of B-cell malignancies, yet technical and commercial challenges using an autologous approach hinder widespread development. Virus-specific T cells present a potential strategy towards an off-the-shelf, allogeneic platform due to the volume of supporting clinical data and additional advantages associated with native TCR engagement to latent virus antigens. Tabelecleucel (tab-cel®) is an investigational off-the-shelf, allogeneic T-cell immunotherapy utilizing native TCR specificity against Epstein-Barr virus (EBV) antigens present in lymphomas and other cancers. With low incidence of GvHD and no cytokine release syndrome, tab-cel® has been shown to be efficacious and well tolerated. Transfer of CAR transgenes into EBV-specific T cells represents an attractive approach to generate off-the-shelf, allogeneic CAR T therapies. We have generated EBV-specific T cells engineered with second generation CD19 CARs as tool compositions to evaluate the potential of this off-the-shelf CAR T approach. Allo-EBV.CD19.CAR T cells express high levels of CD19 CAR and maintain native EBV TCR expression. Allo-EBV.CD19 CAR T cells are predominantly central memory and show CD25, 4-1BB, and IFN-γ activation markers. Functional studies also demonstrate potent antitumor activity against CD19-positive NALM/6 and Raji tumor targets, but no activity against CD19-negative K562 cells. Allo-EBV.CD19.CAR T cells exhibit rapid and comparable killing kinetics compared to CD19.CAR T cells. Allo-CAR T cells also demosntarted antigen-specific proliferation against EBV and CD19-positive targets. Like unmodified EBV-specific T cells, allo.EBV.CD19.CAR T cells maintain the ability to kill B-lymphoblastoid cell lines (BLCL) and little reactivity or inflammatory cytokine secretion in response to HLA mismatched and antigen-negative targets.