The FDA has approved Guardant Health’s Guardant360® CDx liquid biopsy as the first blood-based comprehensive tumor mutation profiling test in patients with any solid cancer tumor—and as a companion diagnostic (CDx) designed to detect epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) patients who may benefit from treatment with AstraZeneca’s Tagrisso® (osimertinib).

The approval makes Guardant360 CDx the first liquid biopsy companion diagnostic that also uses next-generation sequencing (NGS) to identify patients with specific EGFR alterations.

While Guardant360 CDx assay uses NGS to simultaneously detect mutations in 55 tumor genes, the FDA emphasized that genomic findings for other biomarkers besides EGFR mutations are not validated for choosing Tagrisso or any corresponding treatment with the approval granted Friday.

“If the specific NSCLC mutations associated with today’s approval are not detected in the blood, then a tumor biopsy should be performed to determine if the NSCLC mutations are present,” the FDA stated.

That traditional tissue-based approach differs from Guardant’s “blood-first” testing paradigm for personalized oncology treatment selection, which the company says leads to faster and more efficiently targeted treatment.

“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 Health CEO Helmy Eltoukhy, said in a statement. “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 applaud the FDA for their collaborative review process and for approving the first comprehensive genomic profiling liquid biopsy test.”

“A major catalyst”

Investors sent Guardant shares rising about 3.5%, to $85.61 at the close of trading Friday from $82.75 the previous trading day.

“In our view, this is a major catalyst for Guardant and now extends the market lead of G360 in the liquid biopsy comprehensive tumor profiling market,” Puneet Souda, managing director, life sciences tools and diagnostics at SVB Leerink, wrote Friday in an investor note. “Approval as a companion diagnostic for Tagrisso highlights the initial potential of the assay’s use in identifying patients eligible for certain targeted therapies, which we view as a long-term growth factor for GH.”

“The approval elevates the assay in the minds of the oncologists, helps drives adoption across biopharma—ultimately leading to higher growth and revenue for GH longer-term,” Souda added.

Guardant won the FDA approval a day after announcing second-quarter results. The company enjoyed a 23% year-over-year increase in second-quarter revenue, to $66.3 million—of which most (77%) came from the $51 million the company generated in precision oncology revenue, up 21% from Q2 2019. The remaining $15.3 million came from development services revenue, which jumped 29% from a year earlier.

However, a near-doubling of operating expenses—which zoomed 88% $98.5 million vs. $52.4 million in the second quarter of 2019—helped multiply the company’s net loss attributable to common stockholders year over year, to $54.6 million in Q2 from $11.6 million in the year-ago quarter.

Guardant fared better in cash, cash equivalents, and marketable securities, which stood at $1.1 billion as of June 30—up nearly 34% from $822.9 million as of June 30, 2019.

Guardant appears to be planning for future growth. Also on Thursday, Palo Alto, CA, developer Sand Hill Property confirmed to The Mercury News that Guardant signed a lease for 250,000 square feet at 3000 Hanover Street in Palo Alto, CA. The company is headquartered nine miles southeast of Palo Alto in Redwood City, CA.

5,000 samples studied

The FDA based the approval on clinical and analytical validation data from over 5,000 samples. In a retrospective analysis of data from two pivotal Phase III clinical trials, FLAURA (NCT02296125) and AURA3 (NCT02151981), NSCLC patients identified for treatment with Tagrisso through Guardant360 CDx showed progression-free survival rates consistent with those identified using traditional biomarker testing, Guardant said.

FLAURA compared Tagrisso treatment to standard of care EGFR tyrosine kinase inhibitor (TKI), either gefitinib or erlotinib in patients with locally advanced or metastatic NSCLC that is known to be EGFR mutation (EGFRm) positive, treatment-naïve, and eligible for first-line treatment with an EGFR-TKI.

AURA3 compared Tagrisso treatment to chemotherapy for patients with locally advanced or metastatic NSCLC whose disease has progressed with previous EGFR-TKI therapy and whose tumors harbor a T790M mutation within the EGFR gene.

Tagrisso is indicated for first-line treatment of patients with metastatic NSCLC whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 L858R mutations as detected by an FDA-approved test; and treatment of patients with metastatic EGFR T790M mutation-positive NSCLC, as detected by an FDA-approved test, whose disease has progressed on or after EGFR TKI therapy.

The FDA previously granted Guardant360 CDx its Breakthrough Device designation, designed to accelerate the development and prioritize the review of medical devices designed to provide for more effective treatment or diagnosis of life-threatening or irreversibly debilitating diseases or conditions.

Since it was launched in 2014, Guardant360 has been used by more than 7,000 oncologists, over 60 biopharmaceutical companies, and all 28 National Comprehensive Cancer Network Centers in the United States. More than 150,000 Guardant360 tests have been performed to date, while more than 150 peer-reviewed publications have highlighted the use of the liquid biopsy as of August 1—thus demonstrating wide acceptance for blood-based comprehensive genomic profiling, Guardant said.

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