IL1RAP CAR-modified TGFβ1-imprinted NK cells with IL-15 agonist and anti-GD2 antibody significantly reduce Ewing Sarcoma growth and metastasis.

Ewing Sarcoma (ES), particularly in metastatic or relapsed forms, carries a dismal prognosis, highlighting an urgent need for novel therapies. While natural killer (NK) cells demonstrate high cytotoxicity against ES, their efficacy is severely hampered by the immunosuppressive tumor microenvironment (TME), notably through transforming growth factor beta (TGFβ) signaling. Current treatments often fail to overcome this TME resistance, leaving a critical gap in effective, targeted immunotherapies that can sustain NK cell function and persistence.

Researchers developed anti-IL1RAP-CAR-NK cells, with or without TGFβ1-imprinting (imNK), by electroporating anti-IL1RAP-CAR messenger RNA into expanded peripheral blood mononuclear cells. They assessed in vitro cytotoxicity against ES cells, alone or combined with the IL-15 agonist NKTR-255 and/or the anti-GD2 antibody dinutuximab. In vivo efficacy was evaluated in xenograft mouse models of ES. Mechanisms of response were explored using single-cell RNA sequencing and mass cytometry on tumor cells.

Anti-IL1RAP-CAR-NK cells significantly and specifically enhanced NK cytotoxicity in vitro against IL1RAP+ES cells. In vivo, these CAR-NK cells decreased tumor growth and lung metastasis. TGFβ1-imprinting further significantly enhanced in vitro cytotoxicity and tumor infiltration of CAR-NK cells. This led to significantly reduced tumor growth and improved animal survival in the ES orthotopic mouse model. The study found that:

Compared with single agent or double combinations, the triple combination of imprinted-CAR-NK cells with NKTR-255 and dinutuximab showed superior anti-tumor efficacy. This multi-pronged approach effectively circumvented TGFβ-mediated immunosuppression and boosted NK cell activity.