TY - JOUR

T1 - Bispecific T cell-engager targeting oncofetal chondroitin sulfate induces complete tumor regression and protective immune memory in mice

AU - Skeltved, Nanna

AU - Nordmaj, Mie A. A.

AU - Berendtsen, Nicolai T.

AU - Dagil, Robert

AU - Stormer, Emilie M. R.

AU - Al-Nakouzi, Nader

AU - Jiang, Ke

AU - Aicher, Alexandra

AU - Heeschen, Christopher

AU - Gustavsson, Tobias

AU - Choudhary, Swati

AU - Gogenur, Ismail

AU - Christensen, Jan P. P.

AU - Theander, Thor G. G.

AU - Daugaard, Mads

AU - Salanti, Ali

AU - Nielsen, Morten A. A.

PY - 2023

Y1 - 2023

N2 - BackgroundThe malaria protein VAR2CSA binds oncofetal chondroitin sulfate (ofCS), a unique chondroitin sulfate, expressed on almost all mammalian cancer cells. Previously, we produced a bispecific construct targeting ofCS and human T cells based on VAR2CSA and anti-CD3 (V-aCD3(Hu)). V-aCD3(Hu) showed efficacy against xenografted tumors in immunocompromised mice injected with human immune cells at the tumor site. However, the complex effects potentially exerted by the immune system as a result of the treatment cannot occur in mice without an immune system. Here we investigate the efficacy of V-aCD3(Mu) as a monotherapy and combined with immune checkpoint inhibitors in mice with a fully functional immune system.MethodsWe produced a bispecific construct consisting of a recombinant version of VAR2CSA coupled to an anti-murine CD3 single-chain variable fragment. Flow cytometry and ELISA were used to check cell binding capabilities and the therapeutic effect was evaluated in vitro in a killing assay. The in vivo efficacy of V-aCD3(Mu) was then investigated in mice with a functional immune system and established or primary syngeneic tumors in the immunologically "cold" 4T1 mammary carcinoma, B16-F10 malignant melanoma, the pancreatic KPC mouse model, and in the immunologically "hot" CT26 colon carcinoma model.ResultsV-aCD3(Mu) had efficacy as a monotherapy, and the combined treatment of V-aCD3(Mu) and an immune checkpoint inhibitor showed enhanced effects resulting in the complete elimination of solid tumors in the 4T1, B16-F10, and CT26 models. This anti-tumor effect was abscopal and accompanied by a systemic increase in memory and activated cytotoxic and helper T cells. The combined treatment also led to a higher percentage of memory T cells in the tumor without an increase in regulatory T cells. In addition, we observed partial protection against re-challenge in a melanoma model and full protection in a breast cancer model.ConclusionsOur findings suggest that V-aCD3(Mu) combined with an immune checkpoint inhibitor renders immunologically "cold" tumors "hot" and results in tumor elimination. Taken together, these data provide proof of concept for the further clinical development of V-aCD3 as a broad cancer therapy in combination with an immune checkpoint inhibitor.

AB - BackgroundThe malaria protein VAR2CSA binds oncofetal chondroitin sulfate (ofCS), a unique chondroitin sulfate, expressed on almost all mammalian cancer cells. Previously, we produced a bispecific construct targeting ofCS and human T cells based on VAR2CSA and anti-CD3 (V-aCD3(Hu)). V-aCD3(Hu) showed efficacy against xenografted tumors in immunocompromised mice injected with human immune cells at the tumor site. However, the complex effects potentially exerted by the immune system as a result of the treatment cannot occur in mice without an immune system. Here we investigate the efficacy of V-aCD3(Mu) as a monotherapy and combined with immune checkpoint inhibitors in mice with a fully functional immune system.MethodsWe produced a bispecific construct consisting of a recombinant version of VAR2CSA coupled to an anti-murine CD3 single-chain variable fragment. Flow cytometry and ELISA were used to check cell binding capabilities and the therapeutic effect was evaluated in vitro in a killing assay. The in vivo efficacy of V-aCD3(Mu) was then investigated in mice with a functional immune system and established or primary syngeneic tumors in the immunologically "cold" 4T1 mammary carcinoma, B16-F10 malignant melanoma, the pancreatic KPC mouse model, and in the immunologically "hot" CT26 colon carcinoma model.ResultsV-aCD3(Mu) had efficacy as a monotherapy, and the combined treatment of V-aCD3(Mu) and an immune checkpoint inhibitor showed enhanced effects resulting in the complete elimination of solid tumors in the 4T1, B16-F10, and CT26 models. This anti-tumor effect was abscopal and accompanied by a systemic increase in memory and activated cytotoxic and helper T cells. The combined treatment also led to a higher percentage of memory T cells in the tumor without an increase in regulatory T cells. In addition, we observed partial protection against re-challenge in a melanoma model and full protection in a breast cancer model.ConclusionsOur findings suggest that V-aCD3(Mu) combined with an immune checkpoint inhibitor renders immunologically "cold" tumors "hot" and results in tumor elimination. Taken together, these data provide proof of concept for the further clinical development of V-aCD3 as a broad cancer therapy in combination with an immune checkpoint inhibitor.

KW - Immunotherapy

KW - Cancer

KW - Bispecific antibodies

KW - Targeted therapy

KW - VAR2CSA

KW - Checkpoint inhibitor

KW - T cells therapy

KW - T cell memory

KW - ANTIBODY CONSTRUCTS

KW - CANCER

KW - IMMUNOTHERAPY

KW - HYALURONAN

KW - ACTIVATION

KW - EXPRESSION

KW - CD69

U2 - 10.1186/s13046-023-02655-8

DO - 10.1186/s13046-023-02655-8

M3 - Journal article

C2 - 37118819

VL - 42

JO - Journal of Experimental and Clinical Cancer Research (Online)

JF - Journal of Experimental and Clinical Cancer Research (Online)

SN - 1756-9966

M1 - 106

ER -