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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 dual inhibitor Trap-Antibody-Fusion, or TAF, bioconjugate molecule designed to target concurrent inflammation and abnormal angiogenesis observed in the pathogenesis of retinal vascular diseases. KSI-501 acts through an anti-VEGF mechanism and an anti- inflammatory mechanism that targets the potent cytokine IL-6. Similar to KSI-301, KSI-501 uses the ABC Platform and is a bioconjugate of the TAF protein conjugated to our phosphorylcholine-based biopolymer. Preclinical binding and functional studies demonstrate that the TAF protein binds specifically and simultaneously to its intended targets. We believe that this dual inhibition may provide a superior treatment option for patients with retinal vascular diseases and in particular those patients with diseases known to have a high inflammatory component such as DME, as well as in ocular inflammatory diseases such as uveitis.