2seventy bio, a leading immuno-oncology cell therapy company, has announced new data featuring novel approaches combining the company’s platform CAR T cell and T cell receptor technology and unique cell therapy engineering capabilities to potentially enhance treatment potency in a range of cancers. The data were shared in three presentations at this year’s American Society of Gene & Cell Therapy (ASGCT) Annual Meeting in Los Angeles, California.
“We’re excited to present new data related to our programs in acute myeloid leukemia, non-Hodgkin lymphoma and solid tumors,” said Philip Gregory, D.Phil., chief scientific officer, 2seventy bio. “These presentations provide further evidence of our focus on generating potent and targeted anti-tumor activity while limiting toxicity through innovative approaches to controlling T cell responses. With this approach, we believe we can augment the tremendous potential of cell-based immunotherapy, with the goal of advancing next-generation treatments targeting a broad range of cancer types.”
bbT369, a dual-targeted and CBLB gene edited autologous CAR T product for non-Hodgkin lymphoma, showed edit-driven enhanced activity in preclinical in vitro and in vivo models
bbT369 is 2seventy’s novel investigational CD79a/CD20 dual-targeting CBLB gene edited CAR T cell therapy for the treatment of patients with relapsed and/or refractory B-cell non-Hodgkin lymphoma (B-NHL). This preclinical study evaluated the role of the CBLB edit across multiple aspects of CAR T cell function compared to unedited controls. In the study, in vitro assays were designed to model known challenges to maximal CAR T cell activity within the tumor, such as chronic activation, antigen downregulation, and immunosuppression.
- The data demonstrated that the CBLB gene edit significantly enhanced the activity of the bbT369 CAR T cells across each of the in vitro model systems tested.
- bbT369 T cells also drove greater T cell expansion and durable tumor control compared with unedited controls in vivo using a xenograft NSG mouse model.
RESET, a novel TCR coupled antigen receptor architecture, showed targeting sensitivity and pharmacologically- controlled anti-tumor activity in models of acute myeloid leukemia
For some tumors, available target antigens lack ideal expression, necessitating improvements in targeting sensitivity, potency, control, and/or exhaustion mitigation to achieve robust anti-tumor efficacy. While classical CAR T cells require high levels of target antigen for maximum activity, the endogenous T cell receptor (TCR) is significantly more sensitive to low target antigen abundance. To address this gap, a novel receptor architecture called RESET (rapamycin-enabled, switchable endogenous TCR) was developed to more closely mimic TCR activation, thus potentially improving T cell killing of low antigen expression tumor cells. RESET combines the antibody-based targeting of CARs, the drug-regulated activity of the DARIC (a rapamycin-regulated CAR) technology and the natural signaling proficiency and inherent sensitivity of TCRs. The RESET receptor comprises two functional units that are designed to enable toggling of RESET T cells between inert and activated states through rapamycin-induced dimerization:
- When challenged with low antigen density tumor cells in vitro, CD33-targeted RESET T cells (RESET33) were more potently reactive to CD33+ tumor cells after rapamycin dimerization, secreting approximately three times more cytokine than CD33-targeted regulated CAR T cells.
- This enhancement was also observed in preclinical NSG mouse models in vivo, where RESET33 T cells more deeply controlled systemic CD33+ AML tumor models, providing a significant survival benefit in comparison to DARIC33 T cells.
A novel TGFβ switch receptor drove robust MAGE-A4 TCR anti-tumor activity with a favorable safety profile
Solid tumors frequently secrete TGFβ, a pleiotropic cytokine that suppresses T cell responses. To counteract the immunosuppressive effects of TGFβ within engineered T cells, a synthetic receptor (CTBR12) was developed to leverage an immunosuppressive cytokine to convert TGFβ binding into pro-inflammatory signaling events that enhance anti-tumor function:
- T cells co-expressing a pairing enhanced MAGE-A4 TCR with the CTBR12 switch receptor demonstrated robust antigen-dependent responses that were significantly enhanced upon exposure to TGFβ, whereas MAGE-A4 TCR controls lacking CTBR12 were suppressed by this anti-inflammatory cytokine.
- CTBR12 co-expression did not alter the safety profile of the MAGE-A4 TCR.
- In two murine xenograft tumor models with abundant TGFβ, T cells co-expressing the MAGE-A4 TCR and CTBR12 both controlled tumors at T cell doses that elicited only minimal responses without CTBR12 co-expression and exhibited superior durability of response overall.
Source – BusinessWire