Neoadjuvant botensilimab plus balstilimab (BOT/BAL) in resectable mismatch repair proficient and deficient colorectal cancer: NEST-1 clinical trial

In the neoadjuvant NEST-1 colorectal cancer trial, RareCyte’s Orion platform imaged a 13-marker immune-oncology panel on paired pre- and post-treatment tissue, mapping the shift in the tumor immune microenvironment after immunotherapy.

Presented by Weill Cornell Medicine.

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• RareCyte’s Orion instrument imaged all 13 markers of an immune-oncology panel on a single paraffin-embedded slide at 20X. Colon and rectal cancer tissue was stained for the full panel and scanned simultaneously, and paired pre-treatment and post-treatment images resolved the tumor immune microenvironment before and after therapy.
• The tumor immune microenvironment shifted toward an immune-active state after therapy. Across markers including CD4, CD8, CD20, CD68 and FOXP3, post-treatment resections showed increased T cell infiltration, T-regulatory cell depletion, and dendritic-cell and myeloid repolarization relative to matched pre-treatment biopsies.
• The NEST-1 trial reported deep pathologic responses in both colorectal cancer subtypes. Investigators found that 6 of 9 patients with MMR-proficient (MSS) tumors had at least 50% pathologic tumor reduction and all 3 patients with MMR-deficient (MSI-High) tumors had major pathologic responses of at least 90%, the investigational neoadjuvant outcomes the Orion immune analysis was carried out to help explain.