The days of cutting out cancerous tissue to examine under a microscope for a firm diagnosis may be numbered. By next year, Exosome Diagnostics (New York) expects to have blood-based cancer diagnostics on the market.
The company's name is key to its technology. Nanovesicles (30 nm to 100 nm in diameter) circulating in blood and urine, called exosomes, contain unique genetic markers that can be harvested for personalized cancer diagnostics. Exosomes are released from tumor cells to promote tumor growth, angiogenesis and sometimes metastasis. But they also provide biomarkers and that's the niche Exosome Diagnostics is targeting.
"One of the Holy Grails is extracting nucleic acids from blood," CEO James McCullough told Medical Device Daily. "There are a huge number of molecular therapies coming out and they all need companion diagnostics. Being able to detect those key mutations in blood is critical for some indications."
He refers to cancers that are difficult to detect early or require major surgery to obtain a tissue sample, such as brain, pancreatic, lung and ovarian cancers. Who wouldn't want to avoid drilling a hole in the head to diagnose brain cancer? But the technology can be used for any cancer diagnosis and more.
"Exosomes, about the size of a virus, shed precipitously in all body fluids by solid tumors," McCullough said. "We have a normal background of exosomes; our body uses them to communicate between cells. But when you have a tumor, you have a precipitous increase in exosomes which shed into the bloodstream and urine."
He added, "The exosome is a fascinating little thing with a lipid [fat] layer around it that protects it from the activity around it. We believe it's the ultimate package system for tumor-specific nucleic acid. Tumors will put all of their genetic information into them. We isolate those circulated exosomes and, voila, we have a non-invasive way of measuring the tumor."
With various studies completed and data proving the concepts published, Exosome Diagnostics has now partnered with DxS (Manchester, UK) to develop blood-based companion diagnostics for key cancer gene mutations, such as KRAS, BRAF and EGFR. The collaboration will use DxS' Scorpions real-time PCR Mutation Test Kits in conjunction with ExosomeDX's xOS technology, which harvests nucleic acids from blood exosomes.
Initially, the collaboration will focus on developing blood-based measurement of mutations to predict patient response to targeted therapies.
"DxS has the leading diagnostic kit to use in conjunction with our technology to offer tests for specific drugs at big pharmaceutical companies," McCullough said.
He gave an example of potential use: AstraZeneca's (London) Iressa for lung cancer.
"In lung cancer, where tissue biopsies aren't readily available, it would be much easier to use a blood sample," he said.
"So, we can provide pharmaceutical companies with blood-based solutions, but the other way to go with this is with arrays where we measure the full RNA genetic profile in blood," McCullough said. "In that case, we're able to look at developing early stage cancer tests and also monitoring tests."
He said that prototypes of tests are in various stages of development work with "a couple of partners" and with "a lab in the U.S. to launch companion diagnostics and another third party to help us develop the array work."
The company's strategy is to partner with a CLIA-registered lab to launch them as lab tests on a research-use basis and for limited clinical use.
"We are partnering up with an in vitro diagnostic player to manufacture a kit and then we would seek FDA approval," he said. "We're just beginning the regulatory process, but with the CLIA strategy, we can begin sales while we move ahead for regulatory approval."
Regarding Exosome Diagnostics' deal with DxS, McCullough pointed out that there currently are more than 180 companies investigating more than 370 different molecular targeted cancer therapies, many of which will require companion diagnostics. The alliance with an established diagnostic company "is a critical step in providing a solution for pharmaceutical companies, researchers and clinicians to measure the key mutations," he said.
Applications for the blood-based diagnostic technology are broad, including early stage disease detection, staging and monitoring as well as the companion diagnostics. And the technology doesn't seem limited to a type of cancer either.
"So far we've measured mutations in blood of melanoma, prostate, pancreatic, brain, colon and lung cancer," McCullough said. "We haven't tested against a cancer that we couldn't measure."
The next step for the company is a $10 million fundraising to drive the technology through to commercialization.
Published: June 25, 2009