hI-con1™
hI-con1 is a chimeric, IgG-like homodimeric protein composed of a targeting domain (mutated, inactive factor VIIa) fused to an effector domain (IgG Fc) with an intact hinge region. hI-con1 targets Tissue Factor (TF) which is expressed on the luminal surface of many pathologic cells. Such cells include choroidal neovascularization associated with wet age-related macular degeneration (Bora, et. al, 2003), TF-expressing cancer cells (Cocco, et. al. 2010; Kasthuri, et. al. 2009) and tumor-associated pathologic blood vessels (Hu, et. al 1999). TF is not present on the surface of normal cells (Drake et al., 1989; Contrino et al., 1996).
The effector domain of hI-con1 (IgG Fc) triggers immune destruction of hI-con1 targeted cells. The two functional domains of hI-con1 are connected by the hinge region of IgG1 containing two disulfide bonds (See Figure 1). |
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Factor VIIa is an initiator of the clotting cascade and it begins the clotting process by binding very tightly to TF. Consequently, hI-con1 has a very high affinity for TF, an affinity which is much higher than can be achieved by an antibody. In order to prevent unscheduled clotting, the FVIIa domain in hI-con1 has been mutated such that it is defective as a trigger of clotting but its affinity for TF is unchanged. In the GLP safety studies (intravenous and intravitreal) Iconic conducted in support of its wet AMD clinical plan, hI-con1 was not observed to cause any unscheduled bleeding or any signs of disseminated intravascular coagulation [DIC] (data on file at company).
Once hI-con1 is bound to TF on the surface of pathologic blood vessel cells, the immune system is triggered to selectively destroy those cells by dispatching natural killer cells, leaving normal cells unaffected. The antibody domain of hI-con1 that signals the immune system of the patient to dispatch natural killer cells to destroy the target cells is the effector region of hI-con1, an Fc portion of IgG1 (See Figure 2).

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