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In addition to abnormal vessel growth (angiogenesis), inflammation has been implicated in the pathogenesis of several retinal diseases. Anti- inflammatory therapies such as steroids have been effective in treating both uveitis (a spectrum of diseases with intraocular inflammation as a defining characteristic) and DME. Similarly, genetically inherited variations in the interleukin 6, or IL-6, gene have been associated with higher PDR incidence in patients with type 2 diabetes. 

Moreover, disease progression in AMD, DR and RVO have been reported to be associated with increased serum and/or ocular levels of IL-6. Additionally, chronic inflammatory cells have been seen on the surface of the basement membrane behind the retina in eyes with wet AMD. Interestingly, IL-6 has been implicated in resistance to anti-VEGF treatments in DME patients. This in part is believed to be an indirect result of IL-6 mediated upregulation of VEGF expression as well as more direct VEGF-independent angiogenic functions mediated by IL-6 signaling that occur in the presence of VEGF inhibitors.


Our KSI-501 product candidate is a first-in-class bispecific ABC designed to target concurrent inflammation and abnormal angiogenesis observed in the pathogenesis of retinal vascular diseases. KSI-501 is an anti-VEGF and anti-IL-6 biopolymer conjugate designed to provide dual and potent inhibition of (i) VEGF-mediated angiogenesis and vascular permeability through a soluble decoy receptor inhibiting the binding of VEGF-A and PLGF to their cognate receptors and (ii) IL-6 mediated inflammation through an antibody that binds soluble interleukin-6, inhibiting its binding to both soluble and membrane-bound IL-6 receptors.

In preclinical studies KSI-501 was found to inhibit angiogenesis and also normalize inner and outer blood retinal barriers in primary-cell assays. Dual inhibition of VEGF and IL-6 by KSI-501 confers superior normalization of cell morphology and junctional biology compared to either anti-VEGF or anti-IL-6 monotherapy in cell-based assays. We believe KSI-501 has the potential to become a new category of retinal medicines with greater therapeutic efficacy than existing therapies while also benefiting from the promising long-interval durability of Kodiak’s ABC Platform.