In:
Cancer Research, American Association for Cancer Research (AACR), Vol. 78, No. 13_Supplement ( 2018-07-01), p. 2722-2722
Abstract:
While immunotherapies directed against PD-1 and PD-L1 have proven effective across multiple indications, there is still a large unmet medical need for therapies for patients who do not respond or who develop acquired resistance during the course of treatment. There are several emerging hypotheses to explain the lack of response, one of which is the upregulated expression of additional checkpoint receptors, such as TIM-3 and LAG-3, that limit the ability of PD-1 pathway blockade to re-establish effective anti-tumor immunity. To investigate the potential role of TIM-3 and LAG-3 relative to PD-1, we set out to evaluate the expression and function of these receptors in several systems. Firstly, we used a flow cytometry approach to enumerate immune cell populations in a panel of human tumor samples, including non-small cell lung cancer (NSCLC). In these samples, PD-1, TIM-3 and LAG-3 expression was observed in both T-cell and non-T-cell populations. PD-1 was found to be co-expressed with TIM-3 and LAG-3 in CD8+ T-cells and we also found expression of TIM-3 and LAG-3 in other cell types, including regulatory T-cells and myeloid cells. Building on the expression data, we explored the functional effects of targeting these receptors, evaluating the effect of single agent and combination effects of anti-PD-1, anti-TIM-3 and anti-LAG-3 antibodies in mouse models. In these studies, we found not only that dual-blockade of PD-1 with either anti-TIM-3 or anti-LAG-3 resulted in improvements in efficacy over monotherapy, but also that the triple combination of all 3 inhibitors was associated with further anti-tumor activity. In a humanized mouse model of NSCLC, the triple combination was associated with pharmacodynamic effects not only in T-cells, but also reductions in Tregs and macrophages. Taken together, these studies provide further evidence to suggest that in addition to PD-1, LAG-3 and TIM-3 are important emerging immunotherapy targets and provide rationale for not only doublet but also triplet combinations as an approach to cancer therapy. Citation Format: Srimoyee Ghosh, Jon Travers, Kristen McEachern, Sujatha Kumar, Sridhar Ramaswamy, David Jenkins. Investigation of the expression profile and functional role of PD-1, TIM-3 and LAG-3 in human tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2722.
Type of Medium:
Online Resource
ISSN:
0008-5472
,
1538-7445
DOI:
10.1158/1538-7445.AM2018-2722
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2018
detail.hit.zdb_id:
2036785-5
detail.hit.zdb_id:
1432-1
detail.hit.zdb_id:
410466-3
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