90Y-NM600

The combination of ADT and TRT improved antitumor responses in murine models of prostate cancer, however, this was dependent on the order of administration. This was found to be associated with one treatment sequence leading to an increase in infiltrating MDSCs. Combining treatment with a CXCR2 antagonist improved the antitumor effect of this combination, suggesting a possible approach for treating advanced human prostate cancer.

We previously showed that low dose radiation delivery with 90Y-NM600 improves tumor response to immune checkpoint inhibitors (ICIs)... The distinct physical properties of TRT radiation, γ, β or α, affect the timing, magnitude, and molecular pathways leading to this IFN1 response. Understanding TRT effects on the tumor microenvironment may optimize TRT and immunotherapy.

Purpose: In preclinical studies, we have demonstrated that delivering low dose radiation to all tumor sites utilizing 90Y-NM600 improves the response to immune checkpoint inhibitors (ICIs)... These studies demonstrate the capacity to deliver immunomodulatory radiation to tumors using gamma-, beta- or alpha-emitting TRT. The physical properties of the delivered radionuclide dictate timing and magnitude of the IFN1 response stimulated by TRT. Understanding these effects may be critical to safely and effectively integrating TRT and immunotherapies to enhance anti-tumor immunity in cancer patients.

The combination of external beam radiotherapy, intratumoral immunocytokine, and targeted radionuclide immuno-radiotherapy known to have activity against syngeneic melanoma in murine models is feasible and well tolerated in companion dogs with advanced stage, spontaneously arising melanoma or osteosarcoma and has immunomodulatory potential. Further studies evaluating the dose-dependent immunomodulatory effects of this immuno-radiotherapy combination are currently ongoing.

These results suggest a synergistic interaction between BEMPEG and 90Y-NM600 that improves the immune microenvironment in this difficult to treat murine model of HNSCC, which may thereby enhance the response to immune checkpoint blockade. Further studies are warranted to examine the therapeutic implications of this combination in patients.

Combination of 90Y-NM600, BEMPEG, and ICI displays robust anti-tumor activity that prevents metastatic disease progression and prolongs survival in spontaneously metastatic, immunologically “cold” tumor models. Clinical studies are warranted to test the safety and efficacy of this promising combined modality treatment regimen.