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221 SENTI-401, an allogeneic logic-gated and multi-armed CAR-NK cell therapy for the treatment of CEA-expressing solid tumors with enhanced selectivity and efficacy
  1. Alba Gonzalez Junca,
  2. Nicholas Frankel,
  3. Maelig Morvan,
  4. Assen Roguev,
  5. Michelle Hung,
  6. Russell Gordley,
  7. Miguel Palermo,
  8. Tyler Santomaso,
  9. Pearley Chinta,
  10. Aldo Sotelo,
  11. Marcus Gainer,
  12. Derrick Lee,
  13. Tony Hua,
  14. Andrew Banicki,
  15. Mengxi Tian,
  16. Niran Almudhfar,
  17. Atahualpa Contreras,
  18. Chen-Ting Lee and
  19. Timothy Lu
  1. Senti Biosciences, South San Francisco, CA, USA


Background Chimeric Antigen Receptor (CAR)-based cell-therapies have demonstrated clinical benefit in select blood cancers. Unfortunately, their success has yet to be translated to solid tumors. Poor antigen specificity and immune-suppressive mechanisms in the tumor microenvironment (TME) pose key challenges for cell-therapies in the treatment of solid tumors.

Methods SENTI-401, a CAR-NK cell-therapy with NOT Logic Gating and Multi-Arming gene circuits, is designed to overcome the above challenges. SENTI-401 targets CEACAM5 (CEA), a tumor-associated antigen (TAA) highly expressed in solid tumors, including colorectal, pancreatic and lung cancers. SENTI-401 also incorporates NOT Gate technology to overcome on-target off-tumor toxicity from CEA expression by healthy epithelial cells, which has been previously reported when targeting CEA in the clinic.1 Senti is evaluating the effects of multi-arming CAR-NK cells with immunostimulatory payloads to potentially overcome the immunosuppressive TME.

Senti’s novel NOT-Gate technology incorporates an activating (aCAR) targeting a TAA, paired with an inhibitory (iCAR) that recognizes a safety antigen (SA) uniquely expressed on the surface of healthy cells. The NOT-Gate significantly reduces CAR-mediated killing of target cells in a SA-dependent manner, thus mitigating on-target, off-tumor toxicity and allowing targeting of tumor antigens that are broadly expressed by healthy cells.

Results Using our Tumor-Associated Antigen and Safety Antigen Discovery Platform, we discovered and validated VSIG2, a protein on the surface of CEA-expressing healthy epithelial cells and not on tumor cells.

NK cells expressing CEA-targeting aCARs and VSIG2-targeting iCARs receptor pairs had significantly reduced CAR-mediated killing of target cells expressing both CEA and the SA VSIG2, in vitro and in vivo.

To enhance persistence and activity of CAR-NK cells, we developed, calibrated release (cr) technology, which can be coupled to cytokines such as IL-15, resulting in a desired ratio of secreted and surface-bound cytokine to provide autocrine and paracrine functions. The combination of crIL-15 and IL-21 resulted in increased survival and activation of anti-CEA CAR-NK cells, and leading to significantly increased target-cell killing in serial-killing assays. In vivo, anti-CEA CAR-NK cells expressing the both cytokines had superior activity and longer persistence compared to anti-CEA CAR-NK cells. Similarly, we optimized gene-circuits to confer resistance to the immunosuppressive effects of TGFb; anti-CEA CAR-NK cells armed with TGFb-blocking constructs sustained target-cell killing in the continuous presence of TGFb.

Conclusions SENTI-401 incorporates NOT-Gating and Multi-Arming gene-circuits into CAR-NK cells in order to improve the therapeutic window and efficacy of CEA-targeting cell-therapies for the treatment of solid tumors.


  1. Parkhust MR, Yang JC, Langan RC, et al T cells targeting carcinoembryonic antigen can mediate regression of metastatic colorectal cancer but induce severe transient colitis. Mol Ther. 2011 Mar;19(3):620-6 [doi: 10.1038/mt.2010.272.]

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