{
  "abstract": "Background IL-12 is a potent immunostimulatory cytokine whose use as an anti-tumor therapeutic has been limited by severe toxicities associated with systemic administration. Tumor targeting and conditional activation in the tumor microenvironment (TME) are two alternative, potentially complementary, strategies to increase therapeutic index of cytokines. To improve the pharmacokinetics and tolerability of IL-12, we have engineered a masked, protease activated human IL-12Fc with attenuated potency (ZW270). ZW270 is engineered with an internally developed, highly efficient cleavage sequence to provide conditional activation of IL-12Fc in a protease-rich tumor environment. Previous data has shown efficient masking of IL-12Fc activity, improved pharmacokinetics and an expanded therapeutic index of ZW270 in vivo compared to wild type IL-12Fc. ZW270 was well tolerated in non-human primates (>30mg/kg) with slow extended release in the serum.1 While this data demonstrates the benefits of the above combined strategies, additional benefit could be gained by targeting ZW270 to the tumor environment, increasing retention time and further localizing IL-12 activity.Methods To delineate the advantages of targeting a conditionally masked IL-12Fc to the tumor environment, with a tumor targeting Fab, we developed a surrogate masked, protease activated, potency attenuated, mouse IL-12Fc, mZW270. The potency, efficacy and tolerability of a targeted mZW270 was evaluated in vitro and in syngeneic tumor models.Results Targeted mZW270 demonstrated efficient masking and attenuated potency, similar to ZW270, in in vitro splenocyte and reporter gene assays. In vivo, compared to wild type mouse IL-12Fc (no masking, attenuation or targeting), it was better tolerated with no early severe bodyweight loss, highlighting the advantage of combined masking and attenuation strategies. In syngeneic and transgenic models, with varying tumor antigen densities, targeted mZW270 activated a local tumor immune response, leading to strong anti-tumor activity, lowering the minimum effective dose without decreasing the tolerability. Initial characterization of a targeted ZW270 indicated translatability of these observations to a human therapeutic.Conclusions Overall, our combined strategies of masking, potency attenuation and tumor targeting can be incorporated to widen the therapeutic index of an IL-12 based therapeutic.Reference Poffenber, et al. ZW270, a conditionally masked IL-12 cytokine fusion protein displaying potent anti-tumor activity absent systemic toxicity. Cancer Res. 2023;83(7_Supplement):2935. https://doi.org/10.1158/1538-7445.AM2023-2935. AACR 2023",
  "authors": [
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Nichole Escalante"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Sifa Arrafi"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Andrew Sharon"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Minasadat Khoddami"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Gavin Storoschuk"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Alexia Piercey"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Polly Shao"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Ala Ahmed"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Anam Liu"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Larissa Patlan"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Scott Lien"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Catherine Wu"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Richard Kunze"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Maya Poffenberger"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Chayne L Piscitelli"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Paul Moore"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Nina Weisser"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Alexey Berezhnoy"
    },
    {
      "affiliations": [
        "Zymeworks, Vancouver, BC, Canada"
      ],
      "name": "Thomas Spreter von Kreudenstein"
    }
  ],
  "title": "853 Design of a next generation tumor targeted masked IL-12Fc for enhanced tolerability and localized anti-tumor activity",
  "uid": "509822b9-ac35-5771-bfed-6cc2da7d9604"
}