CD46 (complement inhibitory receptor) is a transmembrane immune modulatory receptor that is normally part of the complement system but during tumorigenesis, CD46 is part of the tumor’s immune defense shield.

CD46 is up-regulated in tumor cells to avoid immune surveillance and has been shown to be highly expressed in multiple tumor types. FOR46 is a potent human antibody that recognizes a tumor specific epitope on CD46. While CD46 is expressed throughout the body, preclinical studies show that FOR46 activity is primarily restricted to prostate and other tumor tissue types, as opposed to normal tissue.

To create FOR46, the fully human antibody was conjugated to a potent payload using a proven chemistry platform with well-characterized in vivo properties. FOR46 demonstrated potent in vitro and in vivo anti-tumor activity in preclinical studies. In vitro studies of FOR46 have demonstrated its potential to kill tumor cells with no effect on normal cells. In rodents with human prostate cancer, it eliminated the tumor and led to long-term survival.

The FOR46 program originated at the University of California, San Francisco (UCSF), in the laboratory of Bin Liu, Ph.D. It was identified through an antibody selection process that uses living tumor cells residing in their tissue microenvironment, thereby preserving the natural range of surface antigens present on the cells.

Fortis Therapeutics exclusively licensed rights to the antibody from UCSF, and the company maintains a strong intellectual property position.

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