• New independent clinical evidence from the pivotal TAILORx and RxPONDER trials support the role of the Oncotype DX Breast Recurrence Score ^® test, the only genomic test to predict chemotherapy benefit in early-stage breast cancer patients ^{1 ,2,3,4}
• Initial validation study of a new test to predict radiotherapy benefit will be highlighted in the official SABCS press program, demonstrating Exact Sciences' commitment to supporting patients throughout cancer treatment

MADISON, Wis., Dec. 6, 2022 /PRNewswire/ -- Exact Sciences Corp. (NASDAQ: EXAS), a leading provider of cancer screening and diagnostic tests, today announced that new data presentations supporting the clinical value of its Precision Oncology portfolio will be shared in ten abstracts and three presentations at the 2022 San Antonio Breast Cancer Symposium^® (SABCS^®). The data presented highlight the Oncotype DX Breast Recurrence Score test, Oncomap^™ ExTra test, a new investigational test to predict radiation therapy benefit, and an initial look at Exact Sciences' tumor-naive minimal residual disease (MRD) approach.

"The breadth of evidence presented at SABCS 2022 showcases Exact Sciences' growing Precision Oncology portfolio and commitment to personalizing cancer care and potentially enabling better outcomes at every step," said Rick Baehner, M.D., chief medical officer of Precision Oncology. "We're developing new tests to support cancer patients and strengthening the evidence of our current tests, including updated results from the landmark TAILORx and RxPONDER trials for the Oncotype DX test."

An independently led analysis by ECOG-ACRIN Cancer Research Group with sponsorship from the National Cancer Institute (NCI) will highlight 12-year results from the Trial Assigning IndividuaLized Options for Treatment (Rx) (TAILORx). The largest randomized adjuvant breast cancer trial ever conducted, TAILORx showed that the Oncotype DX^® test identifies the vast majority of women with node-negative disease who receive no substantial benefit from chemotherapy (approximately 80%), as well as the important minority (with a Recurrence Score^® result of 26-100) for whom chemotherapy can be lifesaving.^2,5,6

The new 12-year analysis confirms findings from the original primary analysis that endocrine therapy (ET) is non-inferior to chemotherapy plus ET in patients with hormone receptor (HR)-positive, HER2-negative, node-negative early breast cancer and Recurrence Score results of 11 to 25.⁷ As in the original exploratory analysis², the subgroup of women aged 50 and younger with Recurrence Score results of 16 to 25 derive some chemotherapy benefit that persists out to 12 years. For those with Recurrence Score results of 0 to 25, late recurrence events beyond five years exceeded earlier recurrence; however, risk of distant recurrence at 12 years remains below 10%, still indicating low risk.

"The immediate clinical impact is that with longer follow-up, the main TAILORx study findings remain unchanged. Physicians can continue to use the 21-gene Recurrence Score results to guide decisions about the use of chemotherapy," said Joseph A. Sparano, MD, deputy director of The Tisch Cancer Center at Mount Sinai Health System. Dr. Sparano leads the TAILORx trial on behalf of the ECOG-ACRIN Cancer Research Group.

The Rx for Positive Node, Endocrine Responsive Breast Cancer (RxPONDER) trial demonstrated that the Oncotype DX test identifies the majority of early-stage breast cancer patients with one to three positive lymph nodes who may omit chemotherapy.⁸ An additional exploratory analysis of race and clinical outcomes data in the RxPONDER trial was selected for the SABCS press program. The analysis suggests that Black patients had worse outcomes compared to White patients that were independent of Recurrence Score result, treatment arm and grade.⁹ The underlying causes of the established racial differences in breast cancer risk and outcomes are complex and likely multifactorial, and the effects of socioeconomic factors and other social determinants of health on breast cancer research need to be further explored.

Another analysis of a questionnaire completed by a subset of patients in the RxPONDER trial demonstrated that cancer-related cognitive impairment is greater with chemotherapy plus endocrine therapy than with endocrine therapy alone, and this impairment lasts past three years of follow-up.¹⁰ This analysis reinforces the importance of using the Oncotype DX test to ensure chemotherapy is only used for patients who will benefit. The RxPONDER trial was led by the independent SWOG Cancer Research Network and sponsored by NCI, and its original findings were published in The New England Journal of Medicine in 2021.

A prospective multicenter decision impact study of 680 patients (664 evaluable) with early-stage breast cancer and 1-3 positive nodes demonstrated the clinical and economic value¹¹ of the Oncotype DX test. Specifically, use of the test led to more than half of women being spared chemotherapy (51.7%), a significant improvement in physicians' confidence in their treatment recommendations (55% improvement), and significant cost savings to the healthcare system (£1,7 million).

Oral Presentation: Validation of Profile for the Omission of Local Adjuvant Radiotherapy (POLAR) in a meta-analysis of three randomized controlled trials of breast conserving surgery +/- radiotherapy
Data embargoed until 9 a.m. CT on Friday, December 9
Authors: Karlsson P, et al.
Date/Time: Friday, December 9, 9:30-9:45 a.m. CT
Location: Hall 3

Poster #P3-05-59: ER+ HER2-negative BRCA1/2 carriers breast cancer (BC) patients (n=81): Clinical outcomes and molecular characterization via the 21-gene Recurrence Score (RS) test vs. the general RS-tested population (799,986 samples)
Summary: This is a database cohort comparison of Oncotype DX Recurrence Score results, between patients with germline BRCA1/2 mutations and breast population undergoing Oncotype DX testing. BRCA1/2 carriers are characterized by higher Recurrence Score results and distinct gene expression profiles.¹²
Authors: Yerushalmi R, et al.
Date/Time: Tuesday, December 7, 7:00 a.m. CT

Poster #P2-23-11: Quantitative gene expression by RT-PCR in histologic subtypes of invasive breast carcinoma: an update in nearly one million cases
Summary: This Oncotype DX quantitative gene expression study highlights unique patterns of the Recurrence Score test and single genes across the various histologic subtypes of invasive ductal carcinoma (IDC), suggesting that the Oncotype DX test may be used to further stratify patients with IDC and its histological subtypes.¹³
Authors: Can NT, et al.
Date/Time: Wednesday, December 7, 7:00 a.m. CT

Poster #P2-23-14: Molecular characterization of HER2-low invasive breast carcinoma by quantitative RT-PCR using Oncotype DX^®
Summary: This is a multicenter report comparing Oncotype DX RT-PCR and immunohistochemical molecular characterization of HER2-low in HR+ invasive breast carcinomas.¹⁴  
Authors: Rozenblit M, et al.
Date/Time: Wednesday, December 7, 7:00 a.m. CT

Poster #P2-11-06: Plasma assay of methylated DNA markers (MDM) detects patients with metastatic breast cancer (MBC) compared to healthy controls and treated breast cancer patients with no evidence of disease
Summary: This is a marker discovery study to support a tumor-naive minimal residual disease (MRD) approach. The MDM assay successfully distinguished between patients with metastatic breast cancer and normal healthy control subjects.¹⁵ 
Authors: Giridhar KV, et al.
Date/Time: Wednesday, December 7, 7:00 a.m. CT

Poster #P4-02-12: Validation of a radiation omission signature in early-stage breast cancer patients of the Scottish Conservation Trial
Summary: A study of the 16-gene POLAR signature that successfully identified early-stage breast cancer patients who are at low risk of local regional recurrence from the Scottish Conservation Trial.¹⁶
Authors: Taylor KJ, et al.
Date/Time: Thursday, December 8, 7:00 a.m. CT

Poster #P5-03-15: Application of 21-gene Breast Recurrence Score^® assay to evaluate prognosis and benefit of adjuvant chemotherapy in BRCA1 and BRCA2 pathogenic variant carriers with early stage, estrogen receptor positive breast cancer
Summary: This study shows that women with an inherited BRCA1/2 mutation are more likely to have a higher Oncotype DX Recurrence Score result than their matched controls for age, grade, and stage. These findings suggest that ER+ breast cancers with a germline BRCA1/2 mutation are biologically more aggressive.¹⁷
Authors: Saha P, et al.
Date/Time: Thursday, December 8, 5:00 p.m. CT

Poster #P5-14-12: ESR1-alterations in HR+HER2- breast cancer patients
Summary: An evaluation of ESR1 alterations in HR+ HER2- breast cancer samples sequenced by the Oncomap ExTra assay demonstrated that through comprehensive RNA sequencing, the test was uniquely able to identify both common and rare ESR1 fusions, which occurred most frequently in metastatic samples. This is important to potentially help guide treatment for patients who become refractory to endocrine therapy.¹⁸  
Authors: Basu G, et al.
Date/Time: Thursday, December 8, 5:00 p.m. CT

Poster #P6-01-39: The impact of the 21-gene Recurrence Score^® assay upon physician treatment recommendations in the neoadjuvant setting in lymph node-negative breast cancer patients in Quebec
Summary: A multicenter, prospective Oncotype DX neoadjuvant decision impact study in HR+ lymph-node negative breast cancer patients in Quebec, Canada demonstrated the clinical utility of the test in decreasing the use of chemotherapy in the neoadjuvant setting.¹⁹ 
Authors: Yordanova M, et al.
Date/Time: Friday, December 9, 7:00 a.m. CT

Exact Sciences' Precision Oncology portfolio delivers actionable genomic insights to inform prognosis and cancer treatment after a diagnosis. In breast cancer, the Oncotype DX Breast Recurrence Score^® test is the only test shown to predict the likelihood of chemotherapy benefit as well as recurrence in invasive breast cancer. The Oncotype DX^® test is recognized as a standard of care and is included in all major breast cancer treatment guidelines. The Oncomap^™ ExTra test applies comprehensive tumor profiling, utilizing whole exome and whole transcriptome sequencing, to aid in therapy selection for patients with advanced, metastatic, refractory, relapsed, or recurrent cancer. With an extensive panel of approximately 20,000 genes and 169 introns, the Oncomap ExTra test is one of the most comprehensive genomic (DNA) and transcriptomic (RNA) panels available today. Exact Sciences enables patients to take a more active role in their cancer care and makes it easy for providers to order tests, interpret results, and personalize medicine by applying real-world evidence and guideline recommendations. To learn more, visit precisiononcology.exactsciences.com.

A leading provider of cancer screening and diagnostic tests, Exact Sciences relentlessly pursues smarter solutions providing the clarity to take life-changing action, earlier. Building on the success of Cologuard^® and Oncotype^® tests, Exact Sciences is investing in its product pipeline to support patients before and throughout their cancer diagnosis and treatment. Exact Sciences unites visionary collaborators to help advance the fight against cancer. For more information, please visit the company's website at exactsciences.com, follow Exact Sciences on Twitter @ExactSciences, or find Exact Sciences on Facebook.

NOTE: Oncotype, Oncotype DX, Oncotype DX Breast Recurrence Score, Oncotype DX Breast DCIS Score, Recurrence Score and Oncomap are trademarks or registered trademarks of Genomic Health, Inc. Exact Sciences and Cologuard are trademarks or registered trademarks of Exact Sciences Corporation. All other trademarks and service marks are the property of their respective owners.

This news release contains forward-looking statements concerning our expectations, anticipations, intentions, beliefs or strategies regarding the future. These forward-looking statements are based on assumptions that we have made as of the date hereof and are subject to known and unknown risks and uncertainties that could cause actual results, conditions and events to differ materially from those anticipated. You should not place undue reliance on forward-looking statements. Risks and uncertainties that may affect our forward-looking statements are described in the Risk Factors sections of our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q, and in our other reports filed with the Securities and Exchange Commission. We undertake no obligation to publicly update any forward-looking statement, whether written or oral, that may be made from time to time, whether as a result of new information, future developments or otherwise.

¹ Paik S et al. J Clin Oncol. 2006.
² Sparano JA et al. New Engl J Med. 2018.
³ Geyer CE et al. npj Breast Cancer. 2018.
⁴ Albain KS et al. Lancet Oncol. 2010.
⁵ Hortobagyi GN et al. SABCS 2018.
⁶ Stemmer et al. NPJ Breast Cancer. 2017.
⁷ Sparano JA et al. Abstract #GS1-05, SABCS 2022.
⁸ Kalinsky K et al. New Engl J Med. 2021.
⁹ Abdou Y et al. Abstract #GS1-01, SABCS 2022.
¹⁰ Kang I et al. Abstract #GS1-04, SABCS 2022.
¹¹ Holt SD et al. Poster #P6-01-11, SABCS 2022.
¹² Yerushalmi R, et al. Abstract # P2-23-11, SABCS 2022.
¹³ Can NT et al. Poster #P2-23-11, SABCS 2022.
¹⁴ Rozenblit M et al. Poster #P2-23-14, SABCS 2022.
¹⁵ Giridhar KV et al. Poster #P2-11-06, SABCS 2022.
¹⁶ Taylor KJ et al. Poster #P4-02-12, SABCS 2022.
¹⁷ Saha P et al. Poster #P5-03-15, SABCS 2022.
¹⁸ Basu G et al. Poster #P5-14-12, SABCS 2022.
¹⁹ Yordanova M et al. Poster #P6-01-39, SABCS 2022.

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