Spatially defining immune populations with MultiOmyx™ to predict clinical efficacy

Author: Kirsteen Maclean

Immunotherapy has transformed the treatment of metastatic and recurrent solid tumors, and technological advances in the past few years have created unprecedented opportunities to identify biomarkers of disease progression. Despite these advances, only a minority of patients today respond to immunotherapies. Prediction of response to therapies, such as checkpoint inhibitors that rely on activation of endogenous immune responses, has shown to be especially difficult due to complex and heterogeneous immune escape mechanisms in each patient. One strategy that is under investigation is to enhance specific anti-cancer T-cell responses by augmenting the signaling activity of costimulatory receptors, such as OX40, with agonists. Indeed, OX40 agonists have already been shown to increase antitumor immunity and improve tumor-free survival in preclinical models, demonstrating increased efficacy when given in combination with a PD-1 inhibitor. To that end, a novel humanized IgG1 agonistic OX40 monoclonal antibody, GSK3174998, was incorporated as part of an open-label, non-randomized, multicenter Phase 1 study (NCT02528357) for patients with advanced or returning solid tumors that had progressed after standard treatment. The trial was designed to evaluate the safety, tolerability, and preliminary clinical activity of GSK3174998 as a single agent and in combination with pembrolizumab, the results of which have recently been published by Postel-Vinay et al., 2023 and collaborators1.

The utility of multiplex approaches coupled with advanced software algorithms can be applied to discover cell types, populations and morphological context to provide the necessary spatial distribution of infiltrating immune cells in tumors that allow a detailed characterization of cell-cell association that may help in predicting clinical responses. To understand the antitumor efficacy of OX40 agonism, the group evaluated the expression of phenotypic and functional immune cell markers on tumor-infiltrating lymphocytes and other immune cells using the proprietary MultiOmyx platform offered by NeoGenomics2. The expression of 16 markers and their combinations (CD3, CD4, CD8, granzyme B, FOXP3, Ki-67, ICOS, PD-1, PD-L1, OX40, CD16, CD56, OX40L, HLA-DR, S100, pan cytokeratin (PanCK)), were investigated from paired biopsies from 34 patients and scored using a proprietary algorithm. Furthermore, gene expression analysis was also performed by NeoGenomics on the same tumor samples using the NanoString PanCancer Immune Profiling panel3.

Multiplexed Immunofluorescence analysis

Multiplexed immunofluorescence analysis of baseline and week 6 paired tumor biopsy samples show decreased Treg and increased NK/NKT cell infiltration.

Multiplexed immunofluorescence (mIF) data from paired biopsies suggested that increased infiltration of natural killer (NK)/natural killer T (NKT) cells and decreased regulatory T cells (Tregs) in the tumor microenvironment may contribute to clinical responses. Combinations of CD16+CD56-CD134+ NK /NKT cells and CD3+CD4+FOXP3+CD134+ Tregs exhibited the largest magnitude of change on treatment, whereas CD3+CD8+granzyme B+PD-1+CD134+ cytotoxic T cells were the least variable. Further, tumor gene expression profiling revealed an upregulation of inflammatory responses, T-cell proliferation, and NK cell function on treatment with some inflammatory cytokines upregulated in peripheral blood.

Unfortunately, while the use of mIF and expression profiling provided much needed insight into the cellular composition of specific immune cells within the tumor immune microenvironment (TME) and was much-needed to suggest a clinical response, target engagement as evidenced by pharmacologic activity in peripheral blood and tumor tissue, did not correlate with clinical efficacy and did not support the continued development of GSK3174998±pembrolizumab in advanced solid tumors.


The content in the blogs herein relate to the opinions and views expressed by the individual blog author(s) and contributors and are not necessarily the viewpoints held by NeoGenomics Inc., or any of its affiliates or entities.

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