Q&A: Exosome Diagnostics launches first exosomal RNA-based liquid biopsy test

When it comes to diagnosing cancer, observing RNA has different advantages than just looking at DNA in cancerous cells. Exosome Diagnostics is tapping into the benefits of expanding what’s examined to determine a patient’s diagnosis as well as optimal treatment plans.

Exosome diagnostics

Exosome Diagnostics recently announced the launch of ExoDx Lung(ALK), a liquid biopsy platform that allows for non-invasive detection of biomarkers and potentially negates the need for a tissue biopsy. The test analyzes exosomal RNA from a blood or urine sample and is currently being used to specifically quickly detect certain forms of lung cancer as well as prostate cancer. This is unique in comparison to more standard cell free DNA testing.

The test will help oncologists to identify patients who may benefit from ALK inhibitory therapy among the population of non-small cell lung cancer patients whose tissue samples are unavailable or who are unwilling or unable to undergo repeat biopsy.

In a phone interview, Exosome Diagnostics’ CEO John Boyce shared more about the company’s progress and what’s next.

How is what your doing unique and helpful when it comes to biopsies and successful diagnostics for certain cancer?

There are companies focusing just on cell free DNA testing alone, and there are some problems with that. The cell free DNA only comes from the dying cells, so you’re only basically measuring what’s dying. We all know that one drug is not going to cure cancer – it’s just not going to happen. As you treat a tumor with a drug, you knock off dominant alleles, and as you knock them out you can see them in the bloodstream, but you can’t see the living cells. You can’t measure the living tumor, and you need to see both to determine the next line of therapy. We have an advantage there.

Another thing is that from an early-stage detection standpoint, if you look at a sample of blood, cell free DNA testing is definitely not good enough for some patients in stage one, stage two, and even in stage three with certain cancers. A lot of diagnostic companies share the data they’ve received from stage four patients, but we’re getting sensitivity in early-stage patients because of the exosomal RNA.

Can you explain what exactly an exosome is and it’s significance in this diagnostic process?

Basically they’re a snapshot of a cell itself. They provide the cell free DNA in addition to RNA and protein; most of the genetic material is floating around in there. For a long time, people didn’t know how valuable exosomes were. They thought they were just useless facts floating around in the blood. But back in around 2008, their importance became much more prevalent.

With the RNA, whether a gene is turned on or turned off, that becomes very very important. If you want to see whether a patient is progressing toward or away from a disease, you have to see the RNA. The only place you can get the RNA is from the exosomes, unless you take a chunk of tissue. We get the snapshot from the DNA, but we also get quantitative data from the RNA with our liquid biopsy.

Exosome Diagnostics appears to stand out in its established commercialization of this testing. How does your competition fare?

A lot of big companies are trying to get programs going with this concept. For one, from a legal standpoint, we’ve been doing this for almost 10 years, and most of the solutions for this we’ve patented. We’ve patented the concepts, which can be harder to protect, but we’ve also patented the methods for the specific readouts. A lot of other people doing this will run into our intellectual property, and on top of that, we’re the only ones that are doing this [correlating DNA and RNA] in one step and having the opportunity to combine that information.

The other thing is – rather than just having a diagnostics company working with patients – we have the companion diagnostics piece. We work with pharmaceutical companies to help determine who does and doesn’t respond to drugs.

That is really big business.

Revenues from that will dwarf those of the diagnostic point of view, at least in the beginning stages when it comes to clinical trials and the safety perspective.

Photo: Courtesy of Exosome Diagnostics