151P - Tumor organoid-derived TIL therapy for colorectal cancer

Background

Colorectal cancer (CRC) represents ∼7% of new cancer cases and 11% of cancer deaths worldwide. Tumor-Infiltrating Lymphocyte (TIL) immunotherapy is efficacious against melanoma, but its potency in epithelial cancers such as CRC remains inconsistent. We hypothesized that growing tumor organoids in an Air-Liquid Interface (ALI) system prior to TIL expansion might select for the rare tumor-specific T cells that mediate antitumor activity.

Methods

ALI CRC organoids were generated by embedding intact tumor fragments within a collagen matrix on top of a permeable support membrane exposed to both air and culture medium. This configuration facilitates optimal oxygenation, supporting the growth of faithful mini replicas of original tissue that preserve stroma and tumor-infiltrating immune cells, including cytotoxic T cells. To characterize ALI TILs after ex vivo expansion, cell surface markers were analyzed by flow cytometry and immune gene expression by single-cell RNA sequencing. We also established submerged organoids in vitro and transplanted them as organoid derived xenografts (ODX) in mice to assess antitumor activity. Tumor reactivity and T cell cytotoxicity were measured as cytokine induction and tumor cell death upon in vitro co-culture, while preclinical in vivo efficacy was assessed as tumor growth inhibition.

Results

Our ALI process yielded high cell numbers, mostly comprised of CD4+ and CD8+ T cells of the effector and central memory subtypes. T cell receptor analysis revealed unique sets of polyclonal repertoires, suggestive of tumor specificity. Functionally, ALI TIL tumor reactivity and killing were demonstrated in vitro, that translated to a potent in vivo antitumor activity against autologous ODX models.

Conclusions

Our study presents an innovative TIL immunotherapy approach for CRC. The application of ALI organoid culture conditions prior to the ex vivo TIL expansion resulted in a cell product with appropriate phenotypic and functional features, warranting further development of the novel process.

Legal entity responsible for the study

The authors.

Funding

Khosla Ventures, Peregrine Ventures, Alexandria, Wilson Sonsini.

Disclosure

M. Leushacke: Financial Interests, Institutional, Principal Investigator: Nextvivo. M. Pari, J. Ju, P-Y. Lin, B. Shreshta: Financial Interests, Personal, Stocks/Shares: NextVivo. C. Chartier: Financial Interests, Institutional, Officer: NextVivo.