Critical role of CD206+ macrophages in promoting a cDC1-NK-CD8 T cell anti-tumor immune axis

Neoadjuvant androgen deprivation therapy with or without Fc-enhanced non-fucosylated anti-CTLA-4 (BMS-986218) in high risk localized prostate cancer: a randomized phase 1 trial

Men with high-risk localized prostate cancer exhibit high rates of post-surgical recurrence. In these patients, androgen deprivation therapy (ADT) is immunomodulatory, however increased infiltration of regulatory T cells (Tregs) may limit the antitumor immune effects of ADT. We designed a neoadjuvant clinical trial to test whether BMS-986218 - a next-generation non-fucosylated anti-CTLA-4 antibody engineered for enhanced antibody-dependent cellular cytotoxicity or phagocytosis (ADCC/P) - depletes intratumoral Tregs and augments the response to ADT. In this single-center, two-arm, open-label study, 24 men with high-risk localized prostate cancer were randomized to receive a single dose of ADT with or without two pre-operative doses of BMS-986218 (anti-CTLA4-NF) prior to radical prostatectomy. Treatment was well tolerated and feasible in the neoadjuvant setting. A secondary clinical outcome was the rate of disease recurrence, which was lower than predicted in both arms. Mechanistically, anti-CTLA4-NF reduced ADT-induced Treg accumulation through engagement of CD16a/FCGR3A on tumor macrophages, and depth of Treg depletion was quantitatively associated with clinical outcome. Increased intratumoral dendritic cell (DC) frequencies also associated with lack of recurrence, and pre-clinical data suggest ADCC/P-competent anti-CTLA-4 antibodies elicit activation and expansion of tumor DCs. Patients receiving anti-CTLA4-NF also exhibited phenotypic signatures of enhanced antitumor T cell priming. In total, this study provides the first-in-human evidence of Treg depletion by glycoengineered antibodies targeting CTLA-4 in humans and their potential in combination with ADT in prostate cancer patients with high-risk of recurrence.

Prognostic Significance of CD163+ and/or CD206+ Tumor-Associated Macrophages Is Linked to Their Spatial Distribution and Tumor-Infiltrating Lymphocytes in Breast Cancer

Tumor-associated macrophages (TAMs) is a key element in the breast tumor microenvironment. CD163 and CD206 have been utilized for TAM identification, but the clinical implications of TAMs identified by these markers have not been thoroughly explored. This study conducted a comparative analysis of CD163 and CD206 TAMs using digital image analysis, focusing on their spatial distribution and prognostic significance in relation to tumor-infiltrating lymphocytes (TILs). Distinct clinico-pathological and prognostic characteristics were noted between the two types of TAMs. CD163 TAMs were linked to high-grade tumors (p = 0.006), whereas CD206 TAMs were associated with a higher incidence of nodal metastasis (p = 0.033). CD206 TAMs were predominantly found in the stroma, with more cases being stromal CD206-high (sCD206-high) than tumoral CD206-high (tCD206-high) (p = 0.024). Regarding prognostication, patients stratified according to stromal and tumoral densities of CD163 showed different disease-free survival (DFS) time. Specifically, those that were sCD163-low but tCD163-high exhibited the poorest DFS (chi-square = 10.853, p = 0.013). Furthermore, a high sCD163-to-stromal-TILs ratio was identified as an independent predictor of unfavorable survival outcomes (DFS: HR = 3.477, p = 0.018). The spatial distribution and interactions with TILs enhanced the prognostic value of CD163 TAMs, while CD206 TAMs appeared to have limited prognostic utility in breast cancer cases.

Neoantigen Cancer Vaccines and Different Immune Checkpoint Therapies Each Utilize Both Converging and Distinct Mechanisms that in Combination Enable Synergistic Therapeutic Efficacy

The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to eliminate cancer by expanding and/or sustaining T cells with anti-tumor capabilities. However, whether cancer vaccines and ICT enhance anti-tumor immunity by distinct or overlapping mechanisms remains unclear. Here, we compared effective therapeutic tumor-specific mutant neoantigen (NeoAg) cancer vaccines with anti-CTLA-4 and/or anti-PD-1 ICT in preclinical models. Both NeoAg vaccines and ICT induce expansion of intratumoral NeoAg-specific CD8 T cells, though the degree of expansion and acquisition of effector activity was much more substantial following NeoAg vaccination. Further, we found that NeoAg vaccines are particularly adept at inducing proliferating and stem-like NeoAg-specific CD8 T cells. Single cell T cell receptor (TCR) sequencing revealed that TCR clonotype expansion and diversity of NeoAg-specific CD8 T cells relates to their phenotype and functional state associated with specific immunotherapies employed. Effective NeoAg vaccines and ICT required both CD8 and CD4 T cells. While NeoAg vaccines and anti-PD-1 affected the CD4 T cell compartment, it was to less of an extent than observed with anti-CTLA-4, which notably induced ICOS+Bhlhe40+ Th1-like CD4 T cells and, when combined with anti-PD-1, a small subset of Th2-like CD4 T cells. Although effective NeoAg vaccines or ICT expanded intratumoral M1-like iNOS+ macrophages, NeoAg vaccines expanded rather than suppressed (as observed with ICT) M2-like CX3CR1+CD206+ macrophages, associated with the vaccine adjuvant. Further, combining NeoAg vaccination with ICT induced superior efficacy compared to either therapy in isolation, highlighting the utility of combining these modalities to eliminate cancer.