{
  "abstract": "Background The clinical use of Interleukin 2 (IL-2) is currently limited due to its toxicity and the undesired expansion of regulatory T cells. High-affinity PD-1 binding preferentially enables PD-1-targeted IL2v (‘IL2Rβγ-biased agonists’) to effectively expand tumor-antigen-specific T cells, differentiate these cells into better effectors, and mediate significantly superior anti-tumor efficacy compared to other tumor-targeted IL2v molecules. The expansion and differentiation of antigen-experienced PD1+TCF1+ stem-like CD8+ T cells into effector cells is critical for the success of immunotherapies. However, this approach can still lead to relevant toxicity due to IL2v activity on peripheral PD1- negative cell populations. To address this, we developed an approach that ‘switches on’ IL2v activity specifically in the presence of PD1 positive tumor cells, thereby aiming to increase the therapeutic window of IL2v.Methods We generated a ‘switch-on’ PD-regulated-IL2v bispecific antibody that employs a dual-binding antibody arm capable of specifically and competitively binding to both PD1 or IL2v in a mutually exclusive fashion as shown by X-ray crystallography and a PD-1 targeting blocking Fab in a heterodimeric bispecific antibody format. Its activity was assessed in in vitro assays using human primary cells to measure IL2 receptor (IL2R) signaling. Additionally, we evaluated it in human patient-derived tumor explants (PTEs) to assess T cell expansion and cytokine production. Its efficacy in inhibiting tumor growth was tested in vivo in several syngeneic mouse models.Results X-ray crystallography showed the binding mode of the DBA in complex with PD-1 or IL2v. In vitro assays using human primary cells to measure IL2R signaling through levels of phosphorylated STAT5 (STAT5-P) demonstrated a >150-fold difference in activity in the presence of PD-1 for PD1-reg-IL2v. In human patient-derived tumor explants (PTEs), PD1-reg-IL2v mediated significant expansion of better effector T cells, as well as in the release of e.g. IFNγ, perforin and granzyme B. In vivo studies conducted in several mouse syngeneic tumor models demonstrated that PD1-reg-IL2v inhibits tumor growth with a reduced expansion of circulating activated CD4+ and CD8+ T cells compared to non-regulated PD1-IL2v controls, while maintaining superior efficacy compared to standard-of-care anti-PD1 therapy. Moreover, the peripheral masking improves the pharmacokinetics of PD1-reg-IL2v in comparison to non-masked counterparts.Conclusions These results support the further development of the ‘switch-on’ PD1-reg-IL2v strategy to achieve an increased therapeutic window.",
  "authors": [
    {
      "affiliations": [
        "Roche Innovation Center Zurich, Schlieren, Zürich, Switzerland"
      ],
      "name": "Valeria G Nicolini"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Laura Codarri"
    },
    {
      "affiliations": [
        "pRED TMO, F. Hoffman-La Roche AG, Penzberg, Munich, Germany"
      ],
      "name": "Sabine Imhof-Jung"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Stefanie Briner"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Greta Durini"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Xavier Gueripel"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Silvia Jenni"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Miriam Bez"
    },
    {
      "affiliations": [
        "Roche Innovation Center Zurich, Schlieren, Zürich, Switzerland"
      ],
      "name": "Gabrielle Leclercq"
    },
    {
      "affiliations": [
        "Roche Innovation Center Zürich, Pharma Research and Early Development (pRED), Schlieren, Zürich, Switzerland"
      ],
      "name": "Carmen Yong"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Basel, Basel, Switzerland"
      ],
      "name": "Elzbieta Drozdowicz"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Basel, Basel, Switzerland"
      ],
      "name": "Esther Bommer"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Basel, Basel, Switzerland"
      ],
      "name": "Sara Colombetti"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Basel, Basel, Switzerland"
      ],
      "name": "Ashley Lakner"
    },
    {
      "affiliations": [
        "Roche Innovation Center Zürich, Pharma Research and Early Development (pRED), Schlieren, Zürich, Switzerland"
      ],
      "name": "Sylvia Herter"
    },
    {
      "affiliations": [
        "pRED oDTA, F. Hoffman-La Roche AG, Switzerland, Schlieren, Zürich, Switzerland"
      ],
      "name": "Pablo Umana"
    },
    {
      "affiliations": [
        "Roche Innovation Center Zurich, Schlieren, Zürich, Switzerland"
      ],
      "name": "Christian Klein"
    }
  ],
  "title": "863 A novel bispecific immuno-cytokine therapeutic: ‘switch on’ activity of a conditionally active PD1-IL2v delivering IL2v to PD1+ cells while reducing activity on PD1- cells",
  "uid": "a6469900-02c4-5a2e-8d58-9c450e519c06"
}