Nature Cell Biology, Johan Skog, then a post-doctoral researcher at Massachusetts General Hospital, showed that the genetic signature of cancerous brain cells could be isolated from the exosomes the cells shed. Skog’s discovery led to the formation of Cambridge-based Exosome Diagnostics, which is trying to use exosomes to perform ‘liquid biopsies’—cancer tests from samples of blood or urine. Skog is its chief scientific officer, and Exosome has been running clinical tests to support exosome-based urine and blood tests for prostate and lung cancer. Irving, TX-based Caris Life Sciences is working on exosome technology as well.
In the seven or eight years since Lotvall and Skog published their papers, others have pushed forward the understanding of exosomes and their importance in cancer. In October 2014, Kalluri and colleagues at MD Anderson published a paper in Cancer Cell showing that exosomes shed by breast cancer cells contain not just RNA but large fragments of DNA. They also contain proteins that cause healthy cells to go awry and become tumors. Another paper they published in May showed that exosomes contained genetic signatures of pancreatic cancer, suggesting they might be useful in catching the disease earlier—which would be critical for a fast-moving, deadly cancer that is typically diagnosed too late.
The upshot is, perhaps exosomes, in diagnostics, could lead to periodic blood or urine tests that could produce a real-time look at how a cancer’s DNA is mutating, or responding to treatment. As delivery vehicles, maybe they could help get drugs into tissues they otherwise couldn’t—like pancreatic cancer cells that have proved “intractable” to other methods, Williams says.
That has yet to be proven, but Codiak has licensed MD Anderson’s work, which is to be the foundation for the company’s first efforts into drugs and diagnostics for pancreatic cancer. Williams says Exosome Diagnostics is using a different method to isolate and analyze exosomes, and that it’s focused on different tumor types than Codiak. But there are other challenges ahead for the new startup.
One, for instance, would be manufacturing, at scale, exosome-based drugs that act predictably—that is, the way the company expects them to. Williams says the company envisions doing all this work in-house, in the hopes of it being a simple, “plug and play” procedure. This would involve growing cells in a culture, harvesting exosomes from them, and either using those exosomes themselves as a therapeutic, or stuffing drugs into them—small molecules, antibodies, antibody fragments, RNAs, or otherwise. These exosome drugs would then be injected into a patient. None of this, however, has been done before at a large scale. “The [manufacturing] of exosomes is going to be a real challenge, and something that we’re going to have to focus on, because I think that will give us a real advantage,” he says.
Williams won’t say what drugs would go into these exosomes, or whether they’re new entities or old ones that might work better when delivered in a new way. Step one is proving what Kalluri has seen in mice might work in people. But moving quickly will be critical, given the competition will likely only get more intense from here. Even Williams notes that a lot of companies “have been thinking about exosomes.”
“I do believe that what we’ve been able to do will put us in a great position to be able to commercialize this technology,” he says. “That’s not to say others won’t find a way to do some things in this space, I’m sure they will, that’s always the way it works in this business, but I think our position is a very strong one, and we are arguably, from a therapeutics perspective, the first to really push this forward.”
Eric Lander, the founder of the Broad Institute of MIT and Harvard, is a co-founder of Exosome. Williams says there are other executives on the management team, but wouldn’t disclose their names as of yet in part because “it hasn’t been announced with their companies yet either.”
The Flagship/Arch group has committed more than $80 million to Codiak in two separate venture rounds. Codiak only has access to an unspecified portion of the cash. Williams declined specify the size of the initial investment.
Photo courtesy of flickr user frankieleon via Creative Commons.
