Fuse Biotherapeutics is developing novel immunotherapies for cancer. Our therapeutics are focused on IL-18, a powerful hormone-like protein that is released in response to danger such as cancer to stimulate the immune system, promotes the survival of immune cells that kill tumors, and oppose late stage immune exhaustion. FuseBio’s Functionally-selective IL-18, “F-18”, is built for safety because it is 1 million percent less active in the circulation than the natural cytokine. We have identified a proprietary way to keep F-18 active when brought in close proximity to cells expressing IL-18 receptors without relying on complex biology for success. FuseBio’s most advanced program, PD1-F18, is the first in a new class of IL-18 immunotherapies targeted to PD-1 that is functionally selective by:

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1. Unleashing the activity of IL-18
   by reducing its affinity toward IL-18BP, a “decoy receptor” upregulated in the tumor microenvironment as an immune checkpoint
    

2. Minimizing unwanted off-target effects
   by selectively reducing IL-18’s capacity to bind non-targeted cells
    

3. Maximizing selective activation
   by retaining nearly full activity of IL-18 when targeted to a cell of interest that also expresses the IL-18 receptor in such a way that it is delivered so close to the receptor that F-18 now binds to its receptor

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We are continuing to engineer additional cytokine pathways to complement and expand upon the potential of our lead program.