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They are natural multispecific antibodies recognizing dozens of different epitopes on several antigens. They are not sensitive to individual mutations or mutation escape mechanisms. Polyclonal antibodies are different from and complementary to monoclonal antibodies, with a therapeutic advantage in the main indications where they present a different mode of action. Their broad spectrum avoids off-target toxicity and makes them ideal candidates for attacking complex or highly mutating targets.

Glyco-humanization (GH)

It consists in removing two main xeno-antigens from polyclonal multispecific antibodies. These xeno-antigens are well-established glycans not present in human and mounting toxic immunity when administered to patients.

Low immunogenicity

The technological platform of XENOTHERA allows the production of multispecific glyco-humanized polyclonal antibodies (GH-pAbs). Being devoid of xeno-antigens, notably Neu5Gc, they do not interfere with pre-existing natural humoral immunity of healthy donors as shown in the figure. Their low immunogenicity has been confirmed in patients exposed to various GH-pAbs.


GH-pAb have different mechanisms of action. The Fab region allows to target the antigens and can block receptor or ligand binding to their target. The Fc region induces several biological activities. GH-pAb can notably induce CDC (complement-dependant cytotoxicity), ADCC (antibody-dependant cell cytotoxicity), ADCP (antibody-dependent cellular phagocytosis) and apoptosis. Biological activity includes suppression of unwanted immunity (LIS1), destruction of tumoral cells (XON7, XON5, XON9, LIS22), bacteria opsonphagocytosis (XAB05, XAB06) or neutralization of viruses (XAV19).

scientific papers