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May 28, 2021

Natera Responds to Meritless Lawsuit and Files False Advertising Claim Against Guardant for Misleading Oncologists

AUSTIN, Texas, May 28, 2021 /PRNewswire/ — Natera, Inc. (NASDAQ: NTRA), a pioneer and global leader in cell-free DNA (cfDNA) testing, today announced it has been sued by Guardant Health, in an attempt to stop Natera from exposing Guardant Reveal’s™ true test performance and the differences between tumor-informed and tumor-naive molecular residual disease (MRD) tests.

Natera has filed a claim against Guardant in the U.S. District Court for the Western District of Texas, (Docket No.6:21-cv-00540), alleging that Guardant used false and misleading claims to deceive physicians about the performance capabilities of its MRD test, in violation of the Lanham Act. Guardant’s MRD test performance claims are incomplete or unsupported by clinical evidence, and can be misinterpreted by physicians and patients. 

Natera’s complaint alleges that Guardant has engaged in:

  1. Misleading promotions of 91% sensitivity in the surveillance setting, even though this analysis excluded 7 false negatives without clinical justification (24% of all recurrence events). The test specificity was also not evaluated in this setting, since longitudinal and surveillance samples were not analyzed from the patients who remained relapse-free. It is inappropriate to claim test sensitivity without evaluating specificity in the same population. The only valid sensitivity claim for Guardant’s MRD test uses serial longitudinal samples, and is 69%1 compared to Signatera’s™ 88-93%2-4 sensitivity.
  2. Misleading promotions, including emails to physicians and a presentation at the recent JP Morgan Healthcare Conference, that inappropriately pair a claim of 91% sensitivity with a mismatched claim of 100% specificity. It is highly deceptive to pair sensitivity from one analysis with specificity from a different analysis. It is also inappropriate for Guardant to claim 100% specificity without clarifying that this analysis excluded 2 false positive cases where a full year of clinical follow-up information was not collected, despite having time to do so. This commercial promotion significantly misrepresents the study’s findings and puts patients at risk.
  3. Misleading promotions of its test for use in Stage II-III CRC, using performance claims derived from a study that does not match the intended use population. 19% of the patients included in the Guardant study had Stage IV disease. Patients in the study had an overall recurrence rate of greater than 35% which does not match the Stage II-III intended use population.1 No breakdown of performance was provided for patients with Stage II-III CRC. Furthermore, many patients in the study received neoadjuvant therapy, which makes them less eligible for adjuvant therapy. In addition, test performance was not reported from the post surgical timepoint, which is the time point needed for adjuvant chemotherapy decision making.
  4. Misleading promotions of industry-leading performance, even though Guardant declined to report several unfavorable metrics from its study that are critical for evaluating differences between MRD testing methods. For example, its pre-surgical detection rate was only 47% in patients who did not receive neoadjuvant therapy,1 compared to the tumor-informed Signatera test with reported pre-surgical detection rates of 89-94%.2-4 In addition, Reveal’s diagnostic lead time to detect recurrence was ~4 months1 vs. 8.7 months2 for Signatera, which is a 2x difference.

Natera is committed to free and open dialogue about data that directly impacts clinical decision making and patients’ safety. We look forward to working with the medical and academic community to advance the science of MRD testing, in a transparent manner.

About Natera

Natera is a pioneer and global leader in cell-free DNA testing from a simple blood draw. The mission of the company is to change the management of disease worldwide with a focus on women’s health, oncology, and organ health. Natera operates ISO 13485-certified and CAP-accredited laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) in Austin, Texas and San Carlos, California. It offers proprietary genetic testing services to inform obstetricians, transplant physicians, oncologists, and cancer researchers, including biopharmaceutical companies, and genetic laboratories through its cloud-based software platform. For more information, visit Follow Natera on LinkedIn.

Forward-Looking Statements

All statements other than statements of historical facts contained in this press release are forward-looking statements and are not a representation that Natera’s plans, estimates, or expectations will be achieved. These forward-looking statements represent Natera’s expectations as of the date of this press release, and Natera disclaims any obligation to update the forward-looking statements. These forward-looking statements are subject to known and unknown risks and uncertainties that may cause actual results to differ materially, including with respect to developments in matters under dispute or litigation, our efforts to develop and commercialize new product offerings, whether the results of clinical or other studies will support the use of our product offerings, or our expectations of the reliability, accuracy and performance of our tests. Additional risks and uncertainties are discussed in greater detail in "Risk Factors" in Natera’s recent filings on Forms 10-K and 10-Q and in other filings Natera makes with the SEC from time to time. These documents are available at and


Investor Relations: Mike Brophy, CFO, Natera, Inc., 510-826-2350
Media: Kate Stabrawa, Communications, Natera, Inc., 720-318-4080      


  1. Parikh A, van Seventter EE, Siravegna G, et al. Minimal Residual Disease Detection using a Plasma-Only Circulating Tumor DNA Assay in Colorectal Cancer Patients. Clinical Cancer Research. 2021. DOI: 10.1158/1078-0432.CCR-21-0410
  2. Reinert T, Henriksen TV, Christensen E, et al. Analysis of plasma cell-free DNA by ultradeep sequencing in patients with stages I to III colorectal cancer. JAMA Oncol. 2019;5(8):1124–1131.
  3. Yukami H, Nakamura Y, Watanabe J, et al. Minimal residual disease by circulating tumor DNA analysis for colorectal cancer patients receiving radical surgery: an initial report from CIRCULATE-Japan. ASCO 2021 (virtual conference), Abstract 3608, June 4-8, 2021.

SOURCE Natera, Inc.

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