EVOLVE205, a Highly Potent 2:1 CD20-Targeted CD2 Co-Stimulatory T Cell Engager Engineered for the Treatment of B Cell Malignancies and B Cell Autoimmune Diseases

Introduction: T cell engager (TCE) CD3-bispecifics have improved the treatment of patients with B cell lymphomas leading to recent approvals of the CD20-targeted CD3 bispecifics Glofitamab, Mosunetuzumab, and Epcoritamab for patients with relapsed, refractory diseases. Glofitamab with its 2:1 molecular format has the potential for increased CD20 binding and superior antitumor response compared to conventional 1:1 bispecifics. Recently, drug combinations of CD3-bispecifics and tumor-targeted costimulatory agonists, CD19-4-1BBL and CD19-CD28, have been shown to enhance Glofitamab's efficacy in preclinical models. These combination approaches are currently being investigated in the clinic but may have challenges to establish optimal dose scheduling and dose levels toensure simultaneous CD3 and costimulatory pathway activation. T cell costimulation using CD2 is an alternative strategy that may provide significant benefits compared to 4-1BB and CD28 due to sustained CD2 surface expression on T cell subpopulations including effector T cells. Methods: Here we report on the development of a next-generation 2:1 format EVOLVE with integrated CD2-costimulation to improve CD3-mediated T cell receptor activation and sustain T cell-mediated cytotoxicity by increasing avidity-driven binding and the potential for the formation of alternative tumor-T cell synapses, to achieve potential superior performance to clinical benchmarks. Results: EVOLVE205 with 2:1 molecular format and integrated CD2-costimulatory agonist shows superior cytotoxicity in both high (WSU-DLCL2)and low CD20 (HT) expressing diffuse large B-cell lymphoma cell lines. In an in vitro co-culture assay with HT tumor cells and human PBMCs, EVOLVE205 displays improved human T cell activation, increased T cell expansion, and superior tumor cell killing without a substantial increase in cytokine release compared to 1:1 and 2:1 CD20-targeted clinical benchmark bispecifics. Importantly, in a B-cell depleted PBMC-HT tumor co-culture assay, the tumor-killing potency of EVOLVE205 was improved by up to 60-fold compared to Glofitamab and Epcoritamab, and by over 1,000-fold compared to B-cell depleting therapeutics (BCDTs) such as Rituximab. These data suggest the potential for EVOLVE205 to establish an improved therapeutic index relative to these clinical benchmarks. In a PBMC-engrafted xenograft NSG mouse model with CD20high WSU-DLCL2 cell line, EVOLVE205 showed significant tumor growth inhibition efficacy comparable to Glofitamab. Conclusion: CD20-targeted EVOLVE205 utilizes integrated CD2 costimulation to potently induce T cell activation and tumor killing without mediating significant cytokine release, and demonstrates significant in vivo efficacy, IgG-like pharmacokinetics, and a favorable developability profile. These features of EVOLVE205 appear to offer efficacy and safety advantages compared to clinically available CD20-targeted TCE therapies and BCDTs for the treatment of B cell lymphomas and for B cell-mediated autoimmune diseases.