Targeting IL13Rα2 in melanoma with a bispecific T-cell engager: expression profiling and preclinical evaluation.

Background: Melanoma is a highly aggressive skin cancer, especially in advanced stages. While current treatments such as targeted therapies and immunotherapies have made significant progress, challenges like drug resistance and limited effectiveness in some patients persist. Therefore, ongoing development of novel therapies, particularly for late-stage melanoma, is crucial.

Methods: In this study, we explored the expression of interleukin-13 receptor subunit alpha-2 (IL13Rα2) in melanoma patient-derived xenograft models. We investigated IL13Rα2 as a potential target for melanoma treatment by employing an IL13Rα2-CD3 bispecific T-cell engager (BTE). We tested the effect of IL13Rα2-CD3 BTE on T cell activity by flow cytometry. We studied the potency of IL13Rα2-CD3 BTE in tumor killing assay in vitro. For in vivo studies, we administered DNA expression cassettes encoding IL13Rα2-CD3 BTE (IL13Rα2-CD3 DNA encoding BTE (dBTE)) into immunodeficient mice for direct in vivo expression. The mice were challenged with A375 cells and then treated with IL-13Rα2-CD3 dBTE versus control and reconstituted with human peripheral blood mononuclear cells (PBMCs) or T cells. Tumor development was monitored, and T cell infiltration in the tumor was analyzed throughflow cytometry.

Results: Our findings revealed heterogeneous expression of IL-13Rα2, particularly in samples from advanced stages of melanoma. The IL13Rα2-CD3 BTE facilitated T-cell activation and proliferation by bridging melanoma cells and T cells. We also observed the ability of IL13Rα2-CD3 BTE to direct T cells to kill multiple melanoma patient-derived cell lines through xCELLigence assay in vitro, including those with various mutations associated with late-stage metastatic melanoma. IL13Rα2-CD3 dBTE expressed in vivo led to notable tumor regression through inducing increased T-cell infiltration and activation within the tumor microenvironment.

Conclusions: These promising findings underscore the potential of targeting IL13Rα2 as a relevant target for the development of biologics including dBTE aimed at treating specific subsets of melanoma.