Natera and MEDSIR to Collaborate on the MiRaDoR Trial in Breast Cancer

Key Terms

ctdna medical

Circulating tumor DNA (ctDNA) is tiny fragments of genetic material shed by cancer cells into the bloodstream, like breadcrumbs that can reveal a tumor’s presence and genetic makeup without needing a biopsy. For investors, ctDNA matters because tests and technologies that detect and analyze these fragments can speed diagnosis, track treatment response, and signal relapse, creating commercial opportunities in diagnostics, personalized therapies, and monitoring services.

molecular residual disease medical

Molecular residual disease is the tiny amount of cancer that can remain in the body after treatment and is detectable only by sensitive tests that find cancer DNA or other molecular traces. It matters to investors because these measurements can predict relapse, guide whether additional therapy is needed, and shape the market for diagnostics and drugs—much like finding embers after a fire helps decide if more firefighting is required.

cdk4/6 inhibitor medical

A CDK4/6 inhibitor is a type of cancer drug that blocks two proteins (CDK4 and CDK6) that tell cells to divide, effectively slowing or stopping the growth of tumors. Think of it as cutting power to a photocopier that keeps making cancer cells; that control can shrink tumors or delay progression. For investors, these drugs matter because clinical trial results, regulatory approvals, patent life, safety issues and competition directly affect sales potential and company value.

pik3ca medical

PIK3CA is a gene that helps control cell growth and survival by sending signals inside cells; when it carries certain mutations, those signals can become stuck in the “on” position and drive cancer growth. For investors, PIK3CA matters because its mutations are a biomarker used to identify patients for targeted drugs and diagnostics, affecting clinical trial design, approval chances, and potential market size for therapies aimed at those mutations.

selective estrogen receptor degrader medical

A selective estrogen receptor degrader is a drug that attaches to estrogen receptors in cells and triggers the body to break those receptors down, cutting off the receptor’s ability to respond to estrogen. For investors, these drugs matter because they target hormone-driven cancers and other conditions, so clinical trial results, regulatory approvals, or competitive positioning can strongly affect a biotech or pharma company's revenue prospects and stock value, much like removing the key from a car stops it from running.

Multicenter, Signatera™ Genome-guided interventional trial will evaluate different treatment approaches in HR+/HER2- breast cancer

AUSTIN, Texas--(BUSINESS WIRE)-- Natera, Inc. (NASDAQ: NTRA), a global leader in cell-free DNA and precision medicine, and MEDSIR (Medica Scientia Innovation Research), a global leader in oncology research, today announced their collaboration on the MiRaDoR (NCT05708235) study, which is a multicenter, phase II clinical trial in hormone receptor-positive, HER2-negative (HR+/HER2-) breast cancer.

Breast cancer is the most common cancer in women worldwide, with approximately 2.3 million new cases diagnosed in 2022.¹ Despite advances in treatment, recurrence remains a key concern for patients with HR+/HER2- disease, which represents roughly 70% of all breast cancer cases.²

Funded by F. Hoffman-La Roche Ltd., and sponsored by MEDSIR, MiRaDoR will use Signatera Genome to evaluate the efficacy of different therapeutic approaches in early-stage HR+/HER2- breast cancer. Up to 60 patients who are Signatera-positive without clinical nor radiological evidence of disease recurrence will be sequentially enrolled into one of four treatment arms:

• Arm A: Standard of care endocrine therapy given during the first 90-day period, then patients switch to Arms B, C or D
• Arm B: Giredestrant (oral selective estrogen receptor degrader)
• Arm C: Giredestrant plus Abemaciclib (CDK4/6 inhibitor)
• Arm D: Giredestrant plus Inavolisib (PIK3CA inhibitor; for patients with PIK3CA mutations)

The trial will enable investigators to evaluate serial circulating-tumor DNA (ctDNA) levels in each treatment arm as a predictive marker of treatment response. The study’s primary endpoint is the proportion of patients who have achieved a 90% decrease or clearance in baseline ctDNA after three months of treatment. Participants will have additional Signatera testing at 6, 9 and 12 months, and every six months thereafter until study treatment discontinuation. Results may help determine if specific therapy combinations are more effective in terms of ctDNA decrease than standard of care endocrine treatment.

“Uniting Signatera Genome’s ability to detect molecular residual disease with genomic profiling creates a new standard for precision oncology clinical trials,” said Angel Rodriguez, M.D., senior medical director of oncology at Natera. “In the MiRaDoR trial, investigators are moving beyond surveillance; they are also characterizing the specific genomic driver, PIK3CA, and no longer just asking ‘is the cancer back?’ but also answering 'how do we treat it?’”

Enrollment for MiRaDoR is underway, with several U.K. sites already active and additional site activations expected in Europe in 2026.

References

1. World Health Organization. Breast Cancer Fact Sheet. Last updated August 14, 2025. Available at: https://www.who.int/news-room/fact-sheets/detail/breast-cancer
2. American Cancer Society. Breast Cancer Facts & Figures 2024-2025. Atlanta: American Cancer Society, Inc. 2024.

About Natera

Natera™ is a global leader in cell-free DNA and precision medicine, 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 supported by more than 325 peer-reviewed publications that demonstrate excellent performance. Natera operates ISO 13485-certified and CAP-accredited laboratories certified under the Clinical Laboratory Improvement Amendments (CLIA) in Austin, Texas, and San Carlos, California, and through Foresight Diagnostics, its subsidiary, operates an ISO 27001-certified and CAP-accredited laboratory certified under CLIA in Boulder, Colorado. For more information, visit www.natera.com.

About MEDSIR

Established in 2012, MEDSIR prides itself on working closely with its strategic partners to drive innovation in oncology research. Operating in Spain and the United States, the company provides end-to-end clinical trial management, from study design to publication, with an extensive global network of experts and integrated technology to streamline the process. The company offers proof-of-concept support and a strategic approach that enables research partners to benefit from the best of both worlds: industry clinical research and investigator-driven trials. With the aim of promoting independent research worldwide, MEDSIR has formed a strategic alliance with Oncoclínicas, the leading oncology group in Brazil, which offers outstanding research potential in South America. For further information: www.medsir.org

Forward-Looking Statements (Natera)

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/20251212609556/en/

Contacts (Natera)

Investor Relations: Mike Brophy, CFO, Natera, Inc., investor@natera.com

Media: Lesley Bogdanow, VP of Corporate Communications, Natera, Inc., pr@natera.com

Source: Natera, Inc.