FDA approves Guardant's tumor-sequencing blood test as a Tagrisso lung cancer diagnostic

Guardant Health received a milestone approval from the FDA for its cancer test, as the first liquid biopsy able to genetically profile solid tumors anywhere in the body through a single blood draw.

This can provide oncologists with biomarker and mutation information across 55 genes linked to multiple cancers, without needing to remove samples of the tumor tissue—but the Guardant360 CDx test has not been approved to direct patients toward a particular treatment, in all cases.

The agency did, however, grant the test a new, specific companion diagnostic approval for identifying patients with metastatic non-small cell lung cancer, who may benefit from AstraZeneca’s Tagrisso based on the presence of epidermal growth factor receptor, or EGFR alterations.

In addition, the FDA described Guardant360 as the first approved liquid biopsy test to employ next-generation sequencing technology, for use in high-throughput tumor profiling.

“Approval of a companion diagnostic that uses a liquid biopsy and leverages next-generation sequencing marks a new era for mutation testing,” said Tim Stenzel, director of the Office of In Vitro Diagnostics and Radiological Health at the FDA, which previously gave the test a breakthrough designation.

“In addition to benefiting from less invasive testing, patients are provided with a simultaneous mapping of multiple biomarkers of genomic alterations, rather than one biomarker at a time, which can translate to decreased wait times for starting treatment and provide insight into possible resistance mechanisms,” Stenzel said.

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The test’s companion diagnostic approval was based on data from more than 5,000 blood samples, and a retrospective analysis of data gathered from two of Tagrisso’s phase 3 trials. First introduced and regulated as a lab-developed test, Guardant360 has been used over 150,000 times by more than 7,000 oncologists, according to the company, with results delivered in about seven days.

“The FDA approval of Guardant360 CDx is a landmark decision, demonstrating the value liquid biopsy delivers to oncologists and more importantly, the patients they treat,” Guardant CEO Helmy Eltoukhy said. “Traditional tissue biopsy-based tumor profiling, which is often invasive and has longer turnaround times, can contribute to delays in starting treatment and possibly suboptimal therapy.”

“We are confident that our FDA approval will help accelerate wider adoption of guideline-recommended genomic profiling, increase the number of advanced cancer patients who receive potentially life-changing treatments, and pave the way for new companion diagnostic developments for the Guardant360 CDx,” Eltoukhy added.

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The test is also being developed as a companion diagnostic for targeted cancer treatments by drugmakers such as Amgen and Janssen, and most recently with Radius Health, with a collaboration announced in late July focused on the estrogen receptor degrader elacastrant and its use in breast cancer. Guardant’s work with Janssen was also announced earlier last month, for the EGFR-MET bispecific antibody amivantamab in non-small cell lung cancer.

In its financial results for the second quarter of this year, Guardant saw an increase in revenue despite the spreading COVID-19 pandemic. The company brought in $66.3 million, up 23% compared to last year’s $54.0 million, with nearly 13,700 clinical precision oncology tests performed plus over 2,800 by its biopharmaceutical industry customers. 

However, a large increase in operating expenses compared to 2019 led to a net loss of about $54.6 million. Guardant reported $1.1 billion in cash, cash equivalents and securities as of the end of June, including about $354.6 million in net proceeds from its follow-on public offering that month.