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Exosome-Based Platform Can Predict Early Treatment Response, and Serially and Longitudinally Monitor the Continuing Response, to Immunotherapy in Patients with Malignant Melanoma

Exosome Diagnostics, Inc., a developer of potentially revolutionary, biofluid-based molecular diagnostics, announced on Tuesday, September 29, 2015, data demonstrating the ability of its exosomal RNA (exoRNA) technology platform to predict early response to immunotherapy treatment two to four weeks after treatment initiation, based on mRNA expression changes, and to serially and longitudinally monitor the response in patients with malignant melanoma. The data were presented at a poster session entitled, “Profiling Exosomal mRNAs in Patients Undergoing Immunotherapy for Malignant Melanoma,” at the 18th European Cancer Congress (ECCO) – 40th European Society for Medical Oncology (ESMO) Annual Meeting in Vienna, Austria (September 25-29). A link to the actual poster is provided at the end of this article. “While immunotherapy has emerged as a promising approach to treating cancer, responses vary dramatically among patients. Based on a current dearth of precise diagnostics, critical time elapses before we can determine whether a patient is responding to treatment – time we can’t afford to lose in patients with metastatic melanoma,” said Keith T. Flaherty, M.D., Director of the Henri and Belinda Termeer Center for Targeted Therapies at the Massachusetts General Hospital (MGH) Cancer Center in Boston, Massachusetts, and a co-author of the ECCO-ESMO abstract. “The ability to use exosomal RNA in blood plasma to monitor treatment response and, more so, to predict response represents a breakthrough development that could dramatically accelerate the adoption of immunotherapy treatments by oncologists. I’m excited by these data and look forward to further study of this application for exoRNA analysis.” In the study, exosomal RNA (exoRNA) was isolated from the plasma of 16 patients with malignant melanoma before and after receiving immunotherapy treatment with Ipilimumab. Patients were split into two groups, based upon either a positive or negative response to the therapy (5 responders and 11 non-responders). Plasma was collected pre-treatment (baseline) and the first post-treatment time point (week 2 or week 4). Over 400 genes were detected across all samples and time-points. Eleven control mRNAs with robust detection in all samples were used for normalization. When compared in pre- and post-treatment time point patient samples, the analysis identified nine mRNA species with opposite expression changes, pre- and post-treatment, indicating that these genes are involved in response to immunotherapy treatment. A number of mRNA species showed significant differential expression (p-value<0.05) in patients who responded to treatment and those who did not respond across the time points, indicating the presence of distinct RNA profiles for responders and non-responders.

Overall, these data demonstrate that Exosome Diagnostics’ proprietary exosomal (exoRNA) platform offers the ability to monitor changes in immune pathway genes serially and longitudinally during immunotherapy treatment. In addition, these initial data signal the potential to detect early signature expression changes in mRNA that could distinguish between patients who are likely or unlikely to respond to treatment.

“Each day doctors caring for patients with advanced cancers are faced with difficult treatment decisions, but often lack the information on which to base those decisions. These data show the power of exosomal RNA to shed light on critical genetic-based information to address that gap and, hopefully, guide more informed, real-time treatment decisions,” said Vince O’Neill, M.D., Chief Medical Officer, Exosome Diagnostics (no relation to BioQuick Editor & Publisher Mike O’Neill).

“The ability of exoRNA to reflect changes in expression-based gene signatures is not possible with cell-free DNA-based liquid biopsy approaches, and as a result these approaches are unable to monitor dynamic changes associated with cancer. We’re continually amazed by the versatility of exosomes to yield insights across a multitude of diagnostic indications, both within and beyond the oncology space. It’s an unfolding story, and these immunotherapy-related data mark yet another new and exciting chapter.”

Unlike targeted, personalized cancer treatments, immunotherapy treatments are not linked to specific known underlying mutations. It is difficult for physicians to predict who will respond and, given the current diagnostic landscape, understand if and when a patient is responding to treatment in a time-critical manner.

A key source of nucleic acids, including various species of RNA, including mRNA, exosomes are cell vesicles that are released from the cell and can function as messengers. Exosomes have been found in all living cells studied and are carried throughout the body via biofluids, such as plasma, urine, and cerebrospinal fluid. Using its proprietary exo-RNA-based technology, Exosome Diagnostics can achieve real-time, active access to comprehensive and robust molecular information about cells in the body via a blood draw or urine sample without needing direct access to the cells.

This year, Exosome Diagnostics plans to launch ExoDx™ Lung(ALK) and ExoDx™ Lung(EGFR T790M), plasma-based liquid biopsy tests for non-small cell lung cancer, as well as ExoIntelliScore™ Prostate, a urine-based liquid biopsy test for prostate cancer.

In addition, the company will launch a blood-based liquid biopsy panel targeting 26 of the most important genes and approximately 1000 associated mutations in the most significant pathways implicated in lung, colon, and breast cancers, including EGFR/MAPK and PI3K. The panel will initially be made available to pharmaceutical companies as a clinical development tool. All of the liquid biopsy tests will launch as laboratory developed tests in the company’s certified CLIA laboratory.

To learn more about exosomes, please search BioQuick for "exosomes" and you will find many articles describing multiple aspects of these recently discovered and seemingly incredibly powerful players in a wide range of biology, including clinical medicine.

EXOSOME DIAGNOSTICS

Exosome Diagnostics is a privately held company, based in Cambridge, Massachusetts and focused on developing and commercializing what it believes to be revolutionary biofluid-based diagnostics to deliver personalized precision healthcare that improves lives. The company’s novel exosome-based technology platform, ExoLution™, can yield comprehensive and dynamic molecular insights to transform how cancer and other serious diseases are detected, diagnosed, treated, and monitored. Visit http://www.exosomedx.com to learn more.

[Press release] [Poster PDF] [Exosome Diagnostics]