Study to evaluate effectiveness of switching treatment to elacestrant in early breast cancer based on the detection of molecular relapse with Signatera™

Approximately 1,900 early-stage breast cancer patients to be screened at 120+ sites in Europe

Natera, Inc. (NASDAQ:NTRA), a global leader in cell-free DNA testing, today announced its personalized and tumor-informed molecular residual disease (MRD) test, Signatera, will be used in a new breast cancer study called TREAT ctDNA (EORTC 2129-BCG). This international, multi-center, randomized, phase III clinical trial is being conducted by the European Organisation for Research and Treatment of Cancer (EORTC) Breast Cancer Group in collaboration with Natera and Menarini Group (Menarini), a leading international pharmaceutical and diagnostics company.

The primary objective of the study is to evaluate whether elacestrant (ORSERDU®), a new oral endocrine monotherapy, can delay and/or prevent occurrence of distant metastasis or death compared to standard endocrine therapy in ER+/HER2- early-stage breast cancer patients with molecular relapse, which is defined as the presence of circulating tumor DNA (ctDNA) without clinical or radiographic evidence of recurrence. Over 200 patients who are ctDNA-positive by Signatera will be randomized to continue standard endocrine treatment or switch to elacestrant. Patients in both the control and experimental arms are expected to potentially benefit from timely detection of recurrence.

"We are excited to offer to our high-risk, ctDNA positive, ER+/HER2- early-stage breast cancer patients the possibility to participate in the TREAT ctDNA trial. We aim to study the value of the new selective estrogen receptor degrader (SERD), elacestrant, in reducing the rate of late distant relapses for these patients," said Prof. Michail Ignatiadis, chair of the EORTC Breast Cancer Group and director of the Breast Medical Oncology Clinic and Program at the Jules Bordet Institut.

"We are grateful to partner with EORTC in our efforts to establish the utility of treatment on molecular recurrence, prompted by using Signatera to identify MRD-positive patients before clinically apparent relapse," said Minetta Liu, M.D., chief medical officer of oncology at Natera. "Collaborations with leading clinical trial organizations like EORTC are needed as we seek to demonstrate the power of treatment on molecular recurrence across cancer indications. We believe this represents a paradigm shift in a patient's cancer journey, wherein ctDNA testing may serve as a critical tool to catch relapse earlier, enable treatment while disease burden is still low, and ultimately improve patient outcomes."

The study will screen approximately 1,900 patients across more than 120 sites in 12 countries throughout Europe and is expected to launch before the end of the year.

About Elacestrant (ORSERDU®)

European Union Indication: ORSERDU (elacestrant) was approved by the European Commission in September 2023 as a monotherapy for the treatment of postmenopausal women, and men, with estrogen receptor (ER)-positive, HER2-negative, locally advanced or metastatic breast cancer (mBC) with an activating ESR1 mutation who have disease progression following at least one line of endocrine therapy including a CDK4/6 inhibitor. More information, including prescribing information and important safety information, is available here.

About Signatera

Signatera is a personalized, tumor-informed, molecular residual disease test for patients previously diagnosed with cancer. Custom-built for each individual, Signatera uses circulating tumor DNA to detect and quantify cancer left in the body, identify recurrence earlier than standard of care tools, and help optimize treatment decisions. The test is available for clinical and research use and is covered by Medicare for patients with colorectal cancer, breast cancer (stage IIb and higher) and muscle invasive bladder cancer, as well as for immunotherapy monitoring of any solid tumor. Signatera has been clinically validated across multiple cancer types and indications, with published evidence in more than 50 peer-reviewed papers.

About Natera

Natera™ is a global leader in cell-free DNA testing, dedicated to oncology, women's health, and organ health. We aim to make personalized genetic testing and diagnostics part of the standard of care to protect health, and inform earlier, more targeted interventions that help lead to longer, healthier lives. Natera's tests are validated by more than 150 peer-reviewed publications that demonstrate high accuracy. Natera operates ISO 13485-certified and CAP-accredited laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) in Austin, Texas and San Carlos, California. For more information, visit www.natera.com.

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 whether the results of clinical or other studies will support the use of our product offerings, the impact of results of such studies, our expectations of the reliability, accuracy and performance of our tests, or of the benefits of our 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 www.natera.com/investors and www.sec.gov.

View source version on businesswire.com: https://www.businesswire.com/news/home/20231107253448/en/

Natera Announces Randomized, Phase III TREAT ctDNA Trial in Early-Stage Breast Cancer