Intratumoral Activity of the CXCR3 Chemokine System Is Required for the Efficacy of Anti-PD-1 Therapy.

Despite compelling rates of durable clinical responses to programmed cell death-1 (PD-1) blockade, advances are needed to extend these benefits to resistant tumors. We found that tumor-bearing mice deficient in the chemokine receptor CXCR3 responded poorly to anti-PD-1 treatment. CXCR3 and its ligand CXCL9 were critical for a productive CD8+ T cell response in tumor-bearing mice treated with anti-PD-1 but were not required for the infiltration of CD8+ T cells into tumors. The anti-PD-1-induced anti-tumor response was facilitated by CXCL9 production from intratumoral CD103+ dendritic cells, suggesting that CXCR3 facilitates dendritic cell-T cell interactions within the tumor microenvironment. CXCR3 ligands in murine tumors and in plasma of melanoma patients were an indicator of clinical response to anti-PD-1, and their induction in non-responsive murine tumors promoted responsiveness to anti-PD-1. Our data suggest that the CXCR3 chemokine system is a biomarker for sensitivity to PD-1 blockade and that augmenting the intratumoral function of this chemokine system could improve clinical outcomes.

Chow MT ，Ozga AJ ，Servis RL ，Frederick DT ，Lo JA ，Fisher DE ，Freeman GJ ，Boland GM ，Luster AD ... -  《-》

Anti-PD-1 increases the clonality and activity of tumor infiltrating antigen specific T cells induced by a potent immune therapy consisting of vaccine and metronomic cyclophosphamide.

Weir GM ，Hrytsenko O ，Quinton T ，Berinstein NL ，Stanford MM ，Mansour M ... -  《Journal for ImmunoTherapy of Cancer》

Role of CXCR3 signaling in response to anti-PD-1 therapy.

Tumor mutations and tumor microenvironment are associated with resistance to cancer immunotherapies. However, peripheral T cell in effective anti-programmed death 1 (PD-1) antibody treatment is poorly understood. Mass spectrometry and conventional flow cytometry were used to investigate peripheral blood cells isolated from patients. Furthermore, melanoma mouse model was performed to assess the role of CXCR3 signaling in anti-PD-1 antibody treatment. We revealed a marked increase in the percentage of CXCR3+ T cells in the blood of cancer patients after the first pembrolizumab infusion. This percentage decreased after the second infusion in responsive patients, whereas a sustained high percentage of CXCR3+ T cells was observed in patients with progressive disease. A low percentage of CXCR3+ T cells presented in patients with stable disease or a partial response was confirmed by conventional flow cytometry. Intriguingly, blockade of CXCR3 signaling exacerbated tumor growth in mice. Intratumoral injection with recombinant CXCL9/10 plus intraperitoneal injection of anti-PD1 antibody inhibited the tumor growth in mice. The dynamic changes in CXCR3+ T cells in blood may be a prognostic factor in anti-PD-1 immunotherapy, and promotion of CXCR3-mediated signaling may be beneficial to the anti-PD-1 therapy. FUND: This work was supported by the National Natural Science Foundation of China (Nos. 81722047, 81871944, 81670553, 81874317, 81572389, 81730100) and Jiangsu province key medical talents (Nos. ZDRCA2016026), The "Deng Feng" Distinguished Scholars Program, National Science & Technology Major Project "Key New Drug Creation and Manufacturing Program", China (Number: 2018ZX09201002), and the Fundamental Research Funds for the Central Universities (020814380117).

Han X ，Wang Y ，Sun J ，Tan T ，Cai X ，Lin P ，Tan Y ，Zheng B ，Wang B ，Wang J ，Xu L ，Yu Z ，Xu Q ，Wu X ，Gu Y ... -  《-》

Macrophage-Derived CXCL9 and CXCL10 Are Required for Antitumor Immune Responses Following Immune Checkpoint Blockade.

Response rates to immune checkpoint blockade (ICB; anti-PD-1/anti-CTLA-4) correlate with the extent of tumor immune infiltrate, but the mechanisms underlying the recruitment of T cells following therapy are poorly characterized. A greater understanding of these processes may see the development of therapeutic interventions that enhance T-cell recruitment and, consequently, improved patient outcomes. We therefore investigated the chemokines essential for immune cell recruitment and subsequent therapeutic efficacy of these immunotherapies. The chemokines upregulated by dual PD-1/CTLA-4 blockade were assessed using NanoString-based analysis with results confirmed at the protein level by flow cytometry and cytometric bead array. Blocking/neutralizing antibodies confirmed the requirement for key chemokines/cytokines and immune effector cells. Results were confirmed in patients treated with immune checkpoint inhibitors using single-cell RNA-sequencing (RNA-seq) and paired survival analyses. The CXCR3 ligands, CXCL9 and CXCL10, were significantly upregulated following dual PD-1/CTLA-4 blockade and both CD8+ T-cell infiltration and therapeutic efficacy were CXCR3 dependent. In both murine models and patients undergoing immunotherapy, macrophages were the predominant source of CXCL9 and their depletion abrogated CD8+ T-cell infiltration and the therapeutic efficacy of dual ICB. Single-cell RNA-seq analysis of patient tumor-infiltrating lymphocytes (TIL) revealed that CXCL9/10/11 was predominantly expressed by macrophages following ICB and we identified a distinct macrophage signature that was associated with positive responses to ICB. These data underline the fundamental importance of macrophage-derived CXCR3 ligands for the therapeutic efficacy of ICB and highlight the potential of manipulating this axis to enhance patient responses.

House IG ，Savas P ，Lai J ，Chen AXY ，Oliver AJ ，Teo ZL ，Todd KL ，Henderson MA ，Giuffrida L ，Petley EV ，Sek K ，Mardiana S ，Gide TN ，Quek C ，Scolyer RA ，Long GV ，Wilmott JS ，Loi S ，Darcy PK ，Beavis PA ... -  《-》

Age Correlates with Response to Anti-PD1, Reflecting Age-Related Differences in Intratumoral Effector and Regulatory T-Cell Populations.

Purpose: We have shown that the aged microenvironment increases melanoma metastasis, and decreases response to targeted therapy, and here we queried response to anti-PD1.Experimental Design: We analyzed the relationship between age, response to anti-PD1, and prior therapy in 538 patients. We used mouse models of melanoma, to analyze the intratumoral immune microenvironment in young versus aged mice and confirmed our findings in human melanoma biopsies.Results: Patients over the age of 60 responded more efficiently to anti-PD-1, and likelihood of response to anti-PD-1 increased with age, even when we controlled for prior MAPKi therapy. Placing genetically identical tumors in aged mice (52 weeks) significantly increased their response to anti-PD1 as compared with the same tumors in young mice (8 weeks). These data suggest that this increased response in aged patients occurs even in the absence of a more complex mutational landscape. Next, we found that young mice had a significantly higher population of regulatory T cells (Tregs), skewing the CD8+:Treg ratio. FOXP3 staining of human melanoma biopsies revealed similar increases in Tregs in young patients. Depletion of Tregs using anti-CD25 increased the response to anti-PD1 in young mice.Conclusions: While there are obvious limitations to our study, including our inability to conduct a meta-analysis due to a lack of available data, and our inability to control for mutational burden, there is a remarkable consistency in these data from over 500 patients across 8 different institutes worldwide. These results stress the importance of considering age as a factor for immunotherapy response. Clin Cancer Res; 24(21); 5347-56. ©2018 AACR See related commentary by Pawelec, p. 5193.

Kugel CH 3rd ，Douglass SM ，Webster MR ，Kaur A ，Liu Q ，Yin X ，Weiss SA ，Darvishian F ，Al-Rohil RN ，Ndoye A ，Behera R ，Alicea GM ，Ecker BL ，Fane M ，Allegrezza MJ ，Svoronos N ，Kumar V ，Wang DY ，Somasundaram R ，Hu-Lieskovan S ，Ozgun A ，Herlyn M ，Conejo-Garcia JR ，Gabrilovich D ，Stone EL ，Nowicki TS ，Sosman J ，Rai R ，Carlino MS ，Long GV ，Marais R ，Ribas A ，Eroglu Z ，Davies MA ，Schilling B ，Schadendorf D ，Xu W ，Amaravadi RK ，Menzies AM ，McQuade JL ，Johnson DB ，Osman I ，Weeraratna AT ... -  《-》