Guardant Health's new cancer blood test looks to track tumor mutation in real time

By James Robinson , written on February 11, 2014

From The News Desk

We all want a cure for cancer but the odds are against it. Diseases are rarely cured, in as much as they are made manageable through improved access to medicines and vaccines. Despite how far we’ve come, only two diseases have been completely eradicated: there’s been no new case of Smallpox globally since 1979, and Rinderpest - a viral disease affecting cattle - was eliminated in 2011.

To that end, at the Molecular Medical Tri Conference in San Francisco this morning, Redwood City-based Guardant Health unveiled to 3,000 clinicians a blood test to diagnose and track cancers, which it believes to be a major step in pushing the disease down the path toward being a more preventable, manageable issue.

To accomplish this, Guardant Health focused on improving existing technology to exploit what doctors have always known, that tumor DNA is secreted in very low concentrations into the bloodstream. Guardant spent 24 months working on new digital sequencing technology, taking in $10 million in series A funding in the middle of 2013 from Sequoia Capital. By improving the sensitivity of DNA sequencing tools 100-fold, it found it could detect and recreate the genetic information of a specific tumor simply by analyzing a blood sample.

Guardant360, as the company bills it, is the world’s first “pan-cancer” blood test, capable of, so far, detecting breast, lung, colorectal, skin and prostate cancer. The test allows for tumors to be tracked in real time, without a need for repeat biopsies.

Cancer is a symptom of abnormal gene function and is difficult to treat because tumors themselves mutate. Guardant360 allows doctors access to updated genetic pictures of a patient’s tumor. It is a cheaper, non-invasive method of diagnosis.

According to Guardant Health‘s CEO Helmy Eltoukhy:

Cancer continually changes and the key to treating it is to understand how it mutates. One base mutation in a three billion letter gene is the difference between a treatment working or not. You’re diagnosed with cancer. You have a biopsy and are put on drug A and the cancer goes into remission. A while later the cancer may return and have spread. But doctors will not re-biopsy and will put you back on drug A.

Eltoukhy says for most tumor mutations there is a drug that could work, but 75 percent of cancer patients are taking the wrong drugs because their doctors are working off old information.

Guardant Health tested Guardant360 on 250 patients and found that it could accurately sequence tumor DNA in 90 percent of them. In 60 percent of these cases, it caught treatable tumor mutations in later stage patients.

There was a lot of encouraging signs within this, Eltoukhy says. He points to one patient who was diagnosed with melanoma four years ago and been through three unsuccessful drug therapies. Using Guardant360, researchers were able to track how the cancer had mutated and find a better drug therapy. Within eight weeks, doctors saw a 90 percent tumor reduction.

With Guardant360, Eltoukhy imagines a day when at-risk patients, or patients in remission, are screened for cancers at yearly physicals. He says the potential is there for Guardant 360, if the company gathers enough patient data on how cancer is mutating, to develop algorithms to help them anticipate ahead of time how tumor DNA may change.

It’s a blind spot in the market. By getting ahead of cancer we can collectively begin to make it a comparatively more manageable disease. “$2 billion is spent on cancer research each year, but only $80 million is spent on improving early detection,” Eltoukhy says.

That said, public perceptions of the American health industry are not good. What stops Guardant360 from being an overpriced treatment option only helping the rich? Or worse, what stops medical insurance providers from not covering it, because they don’t want it taking dollars away from less effective treatments that it makes more money on?

Eltoukhy is sensitive to these concerns. Guardant360 won’t be technology that it will license out, rather Guardant Health will be its own service provider. Traditional cancer centers will remain the point of contact. The company is marketing its new test primarily to oncologists as an option. These doctors will draw blood and send samples away to Guardant Health.

“Top cancer centers we’ve dealt with so far have been like kids in a candy store with this new technology,” Eltoukhy says.

He sees the biggest risk for Guardant Health as scaling too quickly with its new product. Trying to tread carefully, it has partnered with a select group of cancer centers across the country for a soft launch, bringing Guardant360 first to a potential pool of 100,000 patients.

Guardant Health sees its new test as a means to democratize cancer treatment. Six hundred thousand tests have been administered since doctors were able to map DNA in unborn children to test for down syndrome. Eltoukhy sees a similar broad adoption if Guardant is successful.

Three people are diagnosed with cancer each minute and there are 14 million new cases each year and 8.2 million deaths. Not to be a grim reaper but there is a significant business opportunity for Guardant360, if it works as well as early tests indicate and the company can scale.

The hurdles are significant, but the possibilities are great.