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February 18, 2020

Natera Files False Advertising Counterclaim Against CareDx

CareDx's advertising obfuscates AlloSure's poor performance

SAN CARLOS, Calif., Feb. 18, 2020 /PRNewswire/ — Natera, Inc. (NASDAQ: NTRA), a pioneer and global leader in cell-free DNA testing, today announced it has filed suit against CareDx for false advertising in the U.S. District Court for Delaware, alleging CareDx used false and misleading claims to deceive physicians about the performance capabilities of its AlloSure test, in violation of the Lanham Act and various Delaware laws prohibiting unfair competition and deceptive trade practices.

Natera, Inc. Logo (PRNewsFoto/Natera, Inc.)

The DART trial (Bloom et al.) and Medicare’s approval of AlloSure relied on exceeding a 1% donor-derived cell-free DNA (dd-cfDNA) test-positive threshold to classify patients with active rejection. CareDx’s advertising materials inappropriately manipulate dd-cfDNA thresholds to mislead physicians about AlloSure’s negative predictive value (NPV) and positive predictive value (PPV). CareDx conceals the interplay between PPV and NPV, routinely showing one performance value without the other corresponding value to mislead physicians about the performance of AlloSure.

Specific examples of how these manipulations are used by CareDx in its advertising, and the potential consequences of them, are detailed in the complaint:

  • In a surveillance setting with a 10% incidence, AlloSure markets a PPV of 44% by changing the threshold to 1.6% rather than the validated 1%. AlloSure’s actual PPV using a 1% threshold is 30%. Doctors using AlloSure in a surveillance setting could perform more biopsies than necessary.
  • AlloSure claims to "rule out rejection" and advertises a 95% NPV. However, in an at-risk cohort where a rule out test would be used to avoid biopsy, AlloSure’s actual NPV is 84% using a 1% threshold.1 With an NPV of 84%, there are more than three times as many false negatives than implied in the advertising material. These claims could cause physicians to order fewer biopsies in patients experiencing rejection, as AlloSure misses 41 out of 100 active rejections.

  • AlloSure promotes a 95% NPV when using a 0.21% threshold, but avoids disclosing the corresponding PPV. The PPV using a 0.21% threshold is 12%, not 44% as advertised. This misrepresentation may lead to 7 of 8 stable patients receiving false positive results, many of whom may receive an unnecessary biopsy.

In addition to manipulating dd-cfDNA thresholds to bolster performance metrics, CareDx attempts to mislead physicians about the performance of AlloSure 3.0 in detecting T cell-mediated rejection (TCMR), which accounts for 30% of all rejections. An independent peer-reviewed manuscript published in 2019 confirms AlloSure’s inability to detect TCMR stating, "we found that dd-cfDNA was not able to discriminate [T]CMR from no rejection."2 

About the Prospera™ dd-cfDNA Organ Transplant Test
Natera offers the Prospera test which leverages Natera’s core single-nucleotide (SNP)-based massively multiplexed PCR (mmPCR) technology to identify allograft rejection non-invasively, with high precision and accuracy, and without the need for prior donor or recipient genotyping. The test works by measuring the fraction of donor-derived cell-free DNA (dd-cfDNA) in the recipient’s blood. It may be used by physicians considering the diagnosis of active rejection, helping to rule in or out this condition when evaluating the need for diagnostic testing or the results of an invasive biopsy. Prospera has been clinically and analytically validated for performance regardless of donor relatedness, rejection type, and clinical presentation.

The test was developed by Natera, Inc. a laboratory certified under the Clinical Laboratory Improvement Amendments (CLIA). This test has not been cleared or approved by the U.S. Food and Drug Administration (FDA). Although FDA does not currently clear or approve laboratory-developed tests in the U.S., certification of the laboratory is required under CLIA to ensure the quality and validity of the tests.

About Natera
Natera is a global leader in cell-free DNA testing. The mission of the company is to change the management of disease worldwide with a focus on reproductive health, oncology, and organ transplantation. Natera operates an ISO 13485-certified and CAP-accredited laboratory certified under the Clinical Laboratory Improvement Amendments (CLIA) in San Carlos, Calif. It offers proprietary genetic testing services to inform physicians who care for pregnant women, 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 expectations of the reliability, accuracy and performance of our screening tests, or of the benefits of our screening tests and product offerings to patients, providers and payers. 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., 650-249-9090
Media: Paul Greenland,


  1. Bloom RD, Bromberg JS, Poggio ED, et al. Cell-Free DNA and Active Rejection in Kidney Allografts. J Am Soc Nephrol. 2017;28(7):2221-2232.
  2. Sigdel TK, Archila FA, Constantin T, et al. Optimizing Detection of Kidney Transplant Injury by Assessment of Donor-Derived Cell-Free DNA via Massively Multiplex PCR. J Clin Med. 2019;8(1):19.


SOURCE Natera, Inc.

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