On December 11, 2025 Exact Sciences Corp. (NASDAQ: EXAS), a leading provider of cancer screening and diagnostic tests, reported the first clinical study results from its Oncodetect molecular residual disease (MRD) test in breast cancer. Findings from the NSABP B-59 substudy, conducted in collaboration with the NSABP Foundation and the German Breast Group (GBG), demonstrated that the Oncodetect test strongly predicts distant recurrence following surgery in patients with early triple-negative breast cancer (TNBC)2, one of the most aggressive and difficult-to-treat breast cancer subtypes.3

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These data, representing one of the largest TNBC MRD datasets analyzed to date,1 were presented by Dr. Marija Balic, MD, PhD, scientific director of the NSABP Translational Research Program, at the San Antonio Breast Cancer Symposium (SABCS). The results demonstrate Oncodetect’s ability to help identify patients at higher risk of recurrence and strengthen the growing clinical evidence supporting the test’s role in guiding post-surgical treatment decisions.

The entities intend to submit these data to a peer-reviewed journal for publication, and Exact Sciences will submit the data to MolDx in support of Medicare coverage.

Prognostic performance of the Oncodetect test in early triple-negative breast cancer

In an analysis of 147 patients from the B-59 substudy, post-surgical detection of circulating tumor DNA (ctDNA) was strongly associated with risk of distant recurrence.2 Patients who remained ctDNA-positive after neoadjuvant therapy and surgery had substantially higher recurrence risk compared to ctDNA-negative patients.2 The key findings include:

Post-surgery MRD-positive status was associated with a ~30-fold higher risk of distant recurrence compared to those who were MRD-negative. 2
95% of patients who were MRD negative after surgery remained free of distant recurrence at 3 years. 2
Neo-adjuvant therapy given before surgical resection, which is the standard of care in patients with TNBC, reduced ctDNA positivity in patients from 95% before the start of treatment to 9% after treatment. 2
These data demonstrate that ctDNA detection after surgery is a powerful prognostic indicator of recurrence risk in TNBC and may help identify patients who could benefit from additional adjuvant therapy.

"The NSABP Foundation is proud to collaborate on this impactful study," said Dr. Norman Wolmark, chairman, NSABP Foundation. "The strength of these data, particularly the clear separation in distant recurrence curves, highlight the prognostic power of ctDNA and its potential to guide post-surgical management strategies for high-risk breast cancer."

Inside the NSABP B-59 study

In partnership with the NSABP Foundation, the Oncodetect substudy was conducted within the NSABP-B-59/GBG-96-GeparDouze trial, which enrolled patients with TNBC receiving neoadjuvant therapy with or without atezolizumab. Blood samples were collected before treatment and after surgery to evaluate whether ctDNA positivity at the post-surgery timepoint was associated with distant recurrence-free interval, with a median follow-up of 37 months. Exact Sciences is also collaborating with the NSABP Foundation on NSABP B-64, a large prospective registry trial enrolling 1,800 participants across all breast cancer subtypes.

"This is an important milestone for our Oncodetect program and for patients facing aggressive breast cancers like TNBC," said Dr. Rick Baehner, senior vice president, chief medical officer, Precision Oncology at Exact Sciences. "These data demonstrate how ctDNA testing can provide critical insights into recurrence risk and more precisely help inform treatment decisions."

(Press release, Exact Sciences, DEC 11, 2025, View Source [SID1234661371])