New Study Published in Clinical Cancer Research Journal Highlights Use of EndoPredict Test to Inform Treatment for Premenopausal Breast Cancer Patients

• Myriad Genetics' EndoPredict test accurately identified premenopausal women with ER+, HER2– breast cancer who could safely avoid adjuvant chemotherapy

SALT LAKE CITY, Aug. 31, 2022 (GLOBE NEWSWIRE) — Myriad Genetics, Inc. (NASDAQ: MYGN), a leader in genetic testing and precision medicine, announced today Clinical Cancer Research, a journal of the American Association for Cancer Research, published a study ¹ that shows the EndoPredict breast cancer prognostic test significantly predicted distant recurrence in premenopausal women with ER+, HER2– early–stage breast cancer. This newly published study represents the first clinical validation of EndoPredict in a solely premenopausal population.

The study — first presented in an abstract at the 2021 ASCO Annual Meeting by Anastasia Constantinidou et al² — examined tumor samples from 385 premenopausal women with ER+, HER2– primary breast cancer who had not received chemotherapy. The results show EndoPredict accurately identified premenopausal women with and without affected lymph nodes who could safely avoid adjuvant chemotherapy as part of their treatment plans due to a very low recurrence risk.

"This important publication on the new EndoPredict data demonstrates our ongoing commitment to advance precision medicine for patients with breast cancer," said Dr. Ralf Kronenwett, director of International Medical Affairs, Myriad Genetics. "In light of mounting clinical recommendations to reduce overtreatment in breast cancer, the results are particularly encouraging. With around a third of all new breast cancer cases occurring in patients aged 54 or younger³, using EndoPredict among premenopausal women provides important insights to inform personalized treatment, including whether there's a benefit to using chemotherapy or not."

The study shows that patients with EndoPredict low–risk scores had a 97% distant recurrence free survival (DRFS) versus 76% for high–risk patients. Importantly, 19% of node–positive premenopausal patients had EndoPredict low–risk scores with 100% DRFS and were able to safely avoid chemotherapy and continue onto endocrine therapy alone.

Another key result from an exploratory subgroup analysis within the study found similar DRFS rates in low–risk patients with or without ovarian function suppression (OFS), with less than 5% distant recurrence after 10 years in both groups.

"This important study shows that premenopausal patients with a low–risk EndoPredict score have a good long–term outcome without chemotherapy and may be considered for treatment with endocrine therapy only," said Dr. Anastasia Constantinidou, Bank of Cyprus Oncology Centre and Cyprus Cancer Research Institute. "These findings are relevant to better inform personalized treatment decisions for a large proportion of premenopausal women with ER+, HER2– early–stage breast cancer."

About the study
EndoPredict is a prognostic test that predicts patient risk of breast cancer recurrence to help identify who can consider safely forgoing chemotherapy. It analyzes 12 genes to create a molecular score, which is combined with tumor features, such as tumor size and nodal status, to establish a patient risk score (EPclin).

The Clinical Validation of EndoPredict in Premenopausal Women study tested tumor samples from 385 premenopausal women with ER+, HER2– primary breast cancer (pT1–3, pN0–1) who did not receive chemotherapy in addition to endocrine therapy. All samples were retrospectively tested blinded to clinical and outcome data with EndoPredict. Associations of EPclin Risk Scores with 10–year DRFS were evaluated by Cox proportional hazards models and Kaplan–Meier analysis. The primary outcome was 10–year DRFS.

In addition to EPclin, clinical variables of interest included age at diagnosis, tumor size, tumor grade, nodal status, Ki 67 expression, and continuous estrogen receptor (ER) expression and progesterone receptor (PgR) expression.

More information about this study can be found here.

¹ Constantinidou et al. Clin Cancer Res 2022 (https://aacrjournals.org/clincancerres/article/doi/10.1158/1078–0432.CCR–22–0619/708058/Clinical–Validation–of–EndoPredict–in)
² Constantinidou et al 2021 ASCO (https://ascopubs.org/doi/abs/10.1200/JCO.2021.39.15_suppl.537)
³ SEER Cancer Statistics Review, 1975–2016. Bethesda, MD: National Cancer Institute;2019.

About Myriad Genetics
Myriad Genetics is a leading genetic testing and precision medicine company dedicated to advancing health and well–being for all. Myriad develops and offers genetic tests that help assess the risk of developing disease or disease progression and guide treatment decisions across medical specialties where genetic insights can significantly improve patient care and lower healthcare costs. Fast Company named Myriad among the World's Most Innovative Companies for 2022. For more information, visit www.myriad.com.

Myriad, the Myriad logo, BRACAnalysis, BRACAnalysis CDx, Colaris, Colaris AP, MyRisk, Myriad MyRisk, MyRisk Hereditary Cancer, MyChoice CDx, Prequel, Prequel with Amplify, Amplify, Foresight, Precise, FirstGene, Health.Illuminated., RiskScore, Prolaris, GeneSight, and EndoPredict are trademarks or registered trademarks of Myriad Genetics, Inc. 2022 Myriad Genetics, Inc. All rights reserved.

Safe Harbor Statement
This press release contains "forward–looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including statements relating to using EndoPredict among premenopausal women to provide important insights to inform personalized treatment, including whether there's a benefit to using chemotherapy or not. These "forward–looking statements" are management's expectations of future events as of the date hereof and are subject to a number of known and unknown risks and uncertainties that could cause actual results, conditions, and events to differ materially and adversely from those anticipated. Such factors include those risks described in the company's filings with the U.S. Securities and Exchange Commission, including the company's Annual Report on Form 10–K filed on February 25, 2022, as well as any updates to those risk factors filed from time to time in the company's Quarterly Reports on Form 10–Q or Current Reports on Form 8–K.