Liquid Biopsies: The Key to Unlocking the Potential of Personalized Medicine

Feb 08, 2016

Guest post by John Boyce, CEO of Exosome Diagnostics, a diagnostics company based in Cambridge, Massachusetts, which launched the world’s first exosomal RNA-based liquid biopsy last month.

As the field of oncology continues to advance a new paradigm of targeted, personalized medicine, molecular diagnostics are taking center stage. Why? Because even the best targeted therapies cannot benefit patients unless we know exactly who to target – and when.

First, we need to determine precisely which mutations and biomarkers a patient has. With that information, doctors can then match a patient to a relevant targeted therapy or consider a clinical trial. Because we know cancer is incredibly dynamic, second, we need routine monitoring to detect changes and new mutations in order to make adjustments to a patient’s treatment regimen. Molecular diagnostics are a fundamental component of each personalized medicine decision for a patient.

Tissue-based molecular cancer diagnostics were a big step forward in advancing personalized medicine. But we now know that they carry some significant limitations. The amount of tissue available for testing may be scarce. In addition, a tissue sample may not reflect the heterogeneity of all cells in a tumor, so mutations may be missed. And tissue biopsies can only provide a snapshot of the disease at a single point in time. Because they are invasive, regular, repeat biopsies are not really an option. From a utility perspective, tissue biopsies can’t fulfill the need for serial and longitudinal monitoring necessary to continually evaluate a patient’s cancer and make informed, real-time treatment decisions.

You may have seen the recent STAT article about how the MATCH trial – the largest and most prominent personalized medicine clinical trial for cancer patients – has been seriously hindered by the limitations of tissue biopsies.

The very good news is that the solution to this problem is rapidly maturing: liquid biopsies.

Liquid biopsies offer the opportunity to detect critical information about cancer through a biofluid sample, like blood or urine. As a result, they can overcome many of the problems inherent to relying on tissue biopsies. Biofluids can be readily accessed and carry a lower risk of complications for patients than tissue biopsies. Because liquid biopsies are non-invasive, samples can be collected as needed, ensuring sufficient sample quantity and enabling the serial and longitudinal monitoring needed to effectively monitor cancer changes in real-time. And liquid biopsies provide a more comprehensive view of a tumor’s genetic makeup by revealing complete molecular information about a tumor instead of being limited to analyzing a small portion of cells from one part of the tumor.

Within the liquid biopsy space itself, we have seen substantial recent progress. First-generation liquid biopsy platforms, cell-free DNA (cfDNA) and circulating tumor cells (CTCs), carry their own limitations, particularly with respect to accurately identifying rare mutations that are better detected via RNA. At Exosome Diagnostics, we recently launched the world’s first RNA-based liquid biopsy test, with additional launches forthcoming. With the introduction of this new liquid biopsy approach, which is able to isolate RNA on cell messengers known as exosomes, we believe we can detect mutations and biomarkers with increased sensitivity as exosomal RNA originates from the living tumor cells as opposed to cfDNA which is derived from dying cells, leading more patients to take advantage of the benefits of personalized therapy. We’ve also seen early promise of this technology to help monitor patients’ progress on immunotherapies.

What’s additionally exciting to us is that with exosome-based technology, the power of liquid biopsies will not be limited to cancer alone. This technology has potential implications across a broad spectrum of diseases, which will be important to leverage as the reach of personalized medicine continues to expand. In addition, I believe in the coming years we’ll see revolutionary applications of exosome-based liquid biopsies. Imagine if patients with neuromuscular diseases didn’t have to undergo routine painful muscle tissue biopsies, or if we could gain insights about neurological disease from cerebrospinal fluid?

In the near-term future, as the center of the personalized medicine revolution, I believe the Greater Boston area will also lead the way in liquid biopsy innovation. The ecosystem we have here is unparalleled – an amalgamation of all the necessary pieces and players to fully leverage the power of liquid biopsies to unlock the potential of personalized medicine. We look forward to continuing our collaboration with some of the world’s best and brightest researchers and academic institutions here to continue to advance this thrilling area of science to benefit patients.

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