A Phase Ib Study of Preoperative, Locoregional IRX-2 Cytokine Immunotherapy to Prime Immune Responses in Patients with Early-Stage Breast Cancer.

Abstract

To evaluate the safety and feasibility of preoperative locoregional cytokine therapy (IRX-2 regimen) in early-stage breast cancer, and to evaluate for intratumoral and peripheral immunomodulatory activity. Sixteen patients with stage I-III early-stage breast cancer (any histology type) indicated for surgical lumpectomy or mastectomy were enrolled to receive preoperative locoregional immunotherapy with the IRX-2 cytokine biological (2 mL subcutaneous × 10 days to periareolar skin). The regimen also included single-dose cyclophosphamide (300 mg/m²) on day 1 to deplete T-regulatory cells and oral indomethacin to modulate suppressive myeloid subpopulations. The primary objective was to evaluate feasibility (i.e., receipt of therapy without surgical delays or grade 3/4 treatment-related adverse events). The secondary objective was to evaluate changes in stromal tumor-infiltrating lymphocyte score. The exploratory objective was to identify candidate pharmacodynamic changes for future study using a variety of assays, including flow cytometry, RNA and T-cell receptor DNA sequencing, and multispectral immunofluorescence. Preoperative locoregional cytokine administration was feasible in 100% (<i>n</i> = 16/16) of subjects and associated with increases in stromal tumor-infiltrating lymphocytes (<i>P</i> < 0.001). Programmed death ligand 1 (CD274) was upregulated at the RNA (<i>P</i> < 0.01) and protein level [by Ventana PD-L1 (SP142) and immunofluorescence]. Other immunomodulatory effects included upregulation of RNA signatures of T-cell activation and recruitment and cyclophosphamide-related peripheral T-regulatory cell depletion. IRX-2 is safe in early-stage breast cancer. Potentially favorable immunomodulatory changes were observed, supporting further study of IRX-2 in early-stage breast cancer and other malignancies.