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Guardant Health Developing COVID-19 Test, Touts ctDNA Advantages for Pandemic Cancer Testing


NEW YORK – Liquid biopsy firm Guardant Health announced this week that it is developing a high-throughput saliva test for SARS-CoV-2, pivoting from its singular focus on cancer to contribute to what it sees as an emerging need for active viral surveillance and a paucity of tests.

During a call on Thursday discussing the company's first quarter financial results, including an 84 percent year-over-year revenue increase, Guardant CEO and Cofounder Helmy Eltoukhy said that the firm is already conducting substantial R&D on its ability to bring such a test to market and is reaching out to potential customers.

Guardant President and COO AmirAli Talasaz added that the timeline for development of the test — a saliva-based next-generation sequencing viral RNA assay intended to identify active COVID-19 infections — is on the order of weeks.

The move was inspired by the company's own experience implementing a program of voluntary repeat virus testing for its own employees.

"While we were offering third-party surveillance testing for our own employees, we realized there is still a major shortfall with the state of testing. We believe there will be significant testing needs throughout the world for the foreseeable future ... and felt a social responsibility to leverage our expertise to contribute to this need," Talasaz said during the call.

"A few of us, we couldn't actually really sleep well and be at ease with what was happening in terms of lack of testing … and we felt social responsibility that if we can contribute, we have to try to contribute versus trying to be opportunistic during this time of pandemic."

The test is being designed to be "differentiated from currently available testing methodologies so as not to exert additional pressure on the existing supply chain," Talasaz added.

On this point, the company appears to be trying to distinguish its effort from recent announcements by other cancer genomic testing companies planning or offering COVID-19 testing using commercially available kits being supplied to many laboratories. Talasaz and other executives stressed that the company is seeking to fill an unmet need, rather than attempting to piggyback on an opportunity for revenue. 

"What we're doing is really [trying] to be orthogonal to the existing supply chain, to find a methodology that works that could be scaled up aggressively if there is a need. And I want to reiterate, as soon as there is not a need, Guardant is OK getting out of the COVID field," Guardant CFO Derek Bertocci said.

According to Talasaz, Guardant's goal in viral testing will be to offer at least 10,000 tests per day with a turnaround time of 24 to 36 hours initially in California for essential workers in the frontline setting, underserved communities, and employers for surveillance testing of their workforce.

"In terms of timeline, we are in the feasibility phase ... [and] we are talking about an order of weeks [not months]," Talasaz said. "It's a program that's making progress very quickly and I think we should be able to have some updates in the near future."

Asked by investors participating in the call about early evidence for sensitivity, Talasaz said that the company isn't ready to disclose any data, but that there is nothing emerging so far that suggests the assay would perform worse than available RT-PCR based tests.

The major added contribution the firm is aiming for, he reiterated, is an improvement in throughput enabled by its NGS capability.

Promoting liquid biopsy

Although Guardant reported that its core cancer testing business has been affected by the ongoing coronavirus pandemic — with a slowdown in both clinical and biopharma research testing — the firm argued during the call this week that it sees the current crisis as, at least in some ways, offering a unique opportunity for its liquid biopsy approach.

"The pendulum, at least in April and the late part of March swung towards fear of [infection] over the necessity of matching patients to the most effective therapy as quickly as possible … [but] we do see that there is a silver lining in terms of liquid biopsy being able to uniquely position itself … in the workflow of oncology offices that that need a solution like this to protect their patients from further risk of exposure," Eltoukhy said.

The fact that liquid biopsy cuts through a lot of the logistical challenges of getting access to tissue, "that it's a simple blood draw to get access to that information," has become a selling factor in this new environment, he argued.

As part of its efforts to maximize its ability to provide testing under pandemic constraints, Eltoukhy said Guardant has scaled up an existing home phlebotomy service and has initiated an expanded financial assistance program.

Highlighting a patient case example, Eltoukhy described an 86-year-old woman diagnosed with stage 4 non-small cell lung cancer approximately two and half years ago. Genomic profiling initially revealed an EGFR alteration, which prompted treatment with an oral anti-EGFR TKI that the patient responded positively to before eventually developing resistance.

"In order to determine her next line of therapy [her oncologist] just needed a genomic reassessment of the tumor. However, given the COVID-19 pandemic … He was reluctant to bring her into the office for testing." Using Guardant's mobile phlebotomy services, the doctor "was able to have blood drawn in the safety of her home" and the company's Guardant360 test identified a T790M resistance mutation that made the patient eligible for a new treatment.

According to Eltoukhy, the case example highlights how liquid biopsy may be able to address the needs of patients during what has become a transformative and uniquely challenging period for healthcare.