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858 A bispecific antibody targeting CD40 and EpCAM induces superior anti-tumor effects compared to the combination of the monospecific antibodies
  1. Peter Ellmark1,
  2. Karin Hägerbrand1,
  3. Mattias Levin1,
  4. Laura Von Schantz1,
  5. Adnan Deronic1,
  6. Laura Varas1,
  7. Anna Säll1,
  8. Karin Barchan1,
  9. Doreen Werchau1,
  10. Lill Ljug1,
  11. Mia Thageson1,
  12. Anna Rosen1,
  13. Christina Sakellariou2,
  14. Malin Lindstedt3 and
  15. Peter Ellmark1
  1. 1Alligator Bioscience AB, Lund, Sweden
  2. 2Lund University, Lund, Sweden


Background Alligator has developed a new concept, Neo-X’, to enable antigen presenting cells to efficiently enhance priming of neoantigen-specific T cells, which may be the missing aspect in tumors that lack T cell infiltration. We hypothesize that binding of the CD40 x EpCAM bsAb (4224) to CD40 on DCs and EpCAM on tumor exosomes or tumor debris leads to i) activation of the DC, ii) uptake of the tumor material, iii) cross-presentation of tumor-derived neoantigen (present in exosomes or debris) and iiii) priming of tumor neoantigen-specific T cells, resulting in an increased quantity and/or quality of the tumor-targeting T cell pool. CD40 crosslinking by engagement with a tumor antigen on a tumor cell is required to achieve a functional agonistic effect, and subsequent DC activation will therefore only be achieved in the presence of tumor antigens.

Methods 4224 evaluated in vitro using human monocyte-derived DC, co-cultured with cells expressing EpCAM. In addition the functional effects were evaluated using tumor cell lines and B-cell lines expressing CD40. In vivo, the anti-tumor efficacy of the CD40 x EpCAM bsAb was determined in human CD40 transgenic mice bearing MB49 bladder carcinoma tumors transfected with human EpCAM or controls.

Results In vitro, we have demonstrated that the CD40 x EpCAM bsAb induces tumor target dependent activation of dendritic cells, as analyzed by flow cytometry measuring HLA-DR and CD86 expression on the DC and by measuring IL-12p40 levels in the supernatant. Further, the ability of bsAbs within the Neo-X’ concept to mediate co-localization of tumor debris and CD40 expressing antigen presenting cells depends on the receptor density of the tumor target. In vivo, 4224 displayed a potent, EpCAM-dependent anti-tumor effect with significantly reduced tumor growth and improved survival compared to an equivalent dose of the combination of the monospecific CD40 Ab and EpCAM targeting antibody. The tumor-localizing property of 4224 also shows potential for improved safety compared to CD40 monospecific antibodies. A biodistribution analysis demonstrated that the bispecific 4224 in the RUBY-format displayed similar half-life as the monospecific CD40 mAb in mice.

Conclusions In conclusion, the Neo-X’ concept, by targeting CD40 and a tumor specific antigen, has the potential to mediate an expansion of the tumor-specific T cell repertoire, resulting in increased T cell infiltration and potent anti-tumor effects.

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