Jérôme Galon, PhD
An assay that analyzes key elements of the tumor microenvironment in patients with colon cancer marks the first standardized method for evaluating an individual’s underlying immune system to be developed and sets the pace for tests in other malignancies that could be incorporated into conventional classification paradigms, according to a worldwide group of researchers who collaborated on the project.
The Immunoscore characterizes the number, density, and distribution of CD3-positive lymphocytes and CD8-positive cytotoxic T cells in the tumor core and invasive margins using a combination of automated immunohistochemistry testing and digital pathology. A patient can then be categorized as having a low, intermediate, or high Immunoscore depending upon preset parameters.
The assay has been validated in a study of tumor samples from more than 2600 patients with stages I-III colon cancer, according to results presented at the 2016 ASCO Annual Meeting in June.1
The time to recurrence (TTR) was significantly longer in patients with a high Immunoscore, and the test was able to predict disease-free and overall survival. Additionally, a subgroup of patients with high-risk stage II colon cancer was identified through a low Immunoscore.
The Immunoscore breaks new ground in classifying cancers, said lead investigator Jérôme Galon, PhD, research director of the Laboratory of Integrative Cancer Immunology at the Inserm public research institute in France, who presented the results at ASCO. He also is co-founder of HalioDX, a diagnostic company seeking to commercialize Immunoscore.
“Today, there is not a single host immune characteristic that is taken into account for cancer patients. We don’t know anything about the immune system of a cancer patient because there is not a single standardized assay,” Galon said during the presentation. “In the era of immunotherapy, it is becoming essential to start classifying cancer patients based on immune parameters.”
As research on the new analytical tool moves forward, the Immunoscore could be used to enhance prognostic assessment and therapeutic management in a range of solid tumors, investigators have indicated.2 An assessment of a patient’s innate and adaptive immune responses could predict whether chemotherapy, radiotherapy, or checkpoint blockade immunotherapy agents would be effective.2
“This is a particularly timely finding in the era of immunotherapy, as Immunoscore-based assays could be used to predict which patients would be more likely to benefit from treatment modalities such as checkpoint blockade or whether strategies such as adjuvant therapy or cancer vaccines to prime immunity might be more appropriate,” said the Society for Immunotherapy of Cancer (SITC), which led the formation of the worldwide consortium that developed the Immunoscore.3
“More broadly, the results of the Immunoscore study have potential implications for the field of immune monitoring as a rapid means of determining response to treatment.”
The next step for the Immunoscore will be to incorporate the assay into randomized clinical trials “to stratify the patients based on what will be the first immune-based assay to measure the immune system of a cancer patient,” Galon said in an interview with OncologyLive
Research is underway on Immunoscore tests for hepatocellular carcinoma and brain metastases. 2
In July, HalioDx announced that the Immunoscore Colon test would be available to pathologists in Europe as a laboratory service and to researchers throughout the world by the end of this year.4
Bernard A. Fox, PhD, past president of SITC, said the Immunoscore is not yet ready to be incorporated into clinical practice but that assays evaluating the immune system to predict therapeutic outcomes probably would be introduced within the next 2 years. Fox is chief of the Laboratory of Molecular and Tumor Immunology at the Earle A. Chiles Research Institute at Providence Portland Medical Center in Oregon.
“This is a great step but it’s still a first step and it’s a small step,” Fox said in an interview with OncologyLive
. “There’s going to be additional information that we’re going to get in the next generation.”
How Immunoscore Was Developed
The Immunoscore findings presented at ASCO represent a milestone in an effort to develop a standardized assay that began more than a decade ago and required an unusual international partnership.