• The study, published in Gastroenterology, shows TissueCypher can increase the detection of Barrett’s esophagus (BE) patients with an initial diagnosis of low-grade dysplasia (LGD) who will progress to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC)

FRIENDSWOOD, Texas / Sep 14, 2023 / Business Wire / Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced the publication of data demonstrating that the TissueCypher^® Barrett’s Esophagus test outperformed standard of care pathology review in predicting malignant progression to HGD and EAC in BE patients with an initial diagnosis of LGD. The study findings are available online in Gastroenterology.¹

“The significant variability in pathology diagnoses of Barrett’s esophagus is compounded by the challenges of effectively predicting which patients among the hundreds of thousands who are diagnosed each year are most likely to progress to advanced forms of the disease and/or cancer,” said Jacques Bergman, M.D., Ph.D., study author, leading BE expert and professor of gastrointestinal endoscopy at the University of Amsterdam and the Amsterdam University Medical Centers, the Netherlands. “TissueCypher has the ability to change this paradigm. Using Artificial Intelligence, the test looks deeper into in a patient’s disease than possible through traditional pathology review, providing objective information regarding a patient’s risk of progressing to esophageal cancer that can ensure early access to effective and possibly curative treatments.”

The study evaluated the risk-stratification performance of TissueCypher in 154 BE patients with an initial community-based diagnosis of LGD with known progression/non-progression outcomes who were prospectively followed as part of the Surveillance versus Radiofrequency Ablation (SURF) trial. The study aimed to compare the test’s performance against an international panel of 14 expert and 16 community-based, generalist pathologists from five countries.

In the study, the TissueCypher test demonstrated higher sensitivity in detecting patients who progressed to HGD/EAC when compared to the panel of pathologists (71% vs. mean 63%, range 33-88% across 30 pathologists; p=0.01186). Importantly, TissueCypher identified 43% of the progressors downstaged to NDBE by the pathologists (and 54.4% of the progressors downstaged to NDBE/IND) and could thus be missed by standard of care due to the variability in pathologist diagnoses. Use of the TissueCypher test in combination with pathology review identified 80.4% of patients who progressed, indicating that the test can increase the early detection of progressors when used with pathology. Additionally, patients with NDBE who received TissueCypher high-risk scores progressed to HGD/EAC at a rate of 21.4% within five years, which is higher than the published rate of progression in patients with expert pathologist-confirmed LGD (8.5% within 5 years). This high-risk subset of BE patients who may be missed by standard of care pathology review can be detected early by the TissueCypher test, enabling intervention with endoscopic eradication therapy to prevent development of EAC, or close surveillance to detect dysplasia and EAC at early, treatable stages.

Overall, the study demonstrated that TissueCypher can accurately predict progression to HGD or EAC in BE patients who are initially diagnosed with LGD in a community setting. Further, TissueCypher test results can provide an objective solution to variable pathology review, allowing physicians to make more informed management decisions for their patients, which may include upstaging care for patients at high risk for progression and reducing unnecessary interventions in low-risk patients.

About TissueCypher^® Barrett’s Esophagus Test

The TissueCypher Barrett’s Esophagus test is Castle’s precision medicine test designed to predict future development of high-grade dysplasia (HGD) and/or esophageal cancer in patients with Barrett’s esophagus (BE). The TissueCypher Barrett’s Esophagus test is indicated for use in patients with endoscopic biopsy confirmed BE that is graded non-dysplastic (NDBE), indefinite for dysplasia (IND) or low-grade dysplasia (LGD); its clinical performance has been supported by 12 peer-reviewed publications of BE progressor patients with leading clinical centers around the world. The test received Advanced Diagnostic Laboratory Test (ADLT) status from the Centers for Medicare & Medicaid Services (CMS) in March 2022. More information about the test and disease can be found at www.CastleTestInfo.com.

About Castle Biosciences

Castle Biosciences (Nasdaq: CSTL) is a leading diagnostics company improving health through innovative tests that guide patient care. The Company aims to transform disease management by keeping people first: patients, clinicians, employees and investors.

Castle’s current portfolio consists of tests for skin cancers, uveal melanoma, Barrett’s esophagus and mental health conditions. Additionally, the Company has active research and development programs for tests in other diseases with high clinical need, including its test in development to predict systemic therapy response in patients with moderate-to-severe psoriasis, atopic dermatitis and related conditions. To learn more, please visit www.CastleBiosciences.com and connect with us on LinkedIn, Facebook, X and Instagram.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-SCC, MyPath Melanoma, DecisionDx-UM, DecisionDx-PRAME, DecisionDx-UMSeq, TissueCypher and IDgenetix are trademarks of Castle Biosciences, Inc.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, which are subject to the “safe harbor” created by those sections. These forward-looking statements include, but are not limited to, statements concerning: TissueCypher’s potential to (i) increase the accurate detection of BE patients with initial community-based diagnosis of LGD who will progress to HGD or EAC; (ii) change the standard of care paradigm and use Artificial Intelligence to provide objective information regarding a patient’s risk of progressing to EAC that can ensure early access to effective and possibly curative treatments; (iii) increase the early detection of progressors when used with pathology; (iv) detect a high-risk subset of BE patients and enable intervention with endoscopic eradication therapy to prevent development of EAC, or close surveillance to detect dysplasia and EAC at early, treatable stages; and (v) provide an objective solution to variable pathology review, allowing physicians to make more informed management decisions for their patients, which may include upstaging care for patients at high risk for progression and reducing unnecessary interventions in low-risk patients. The words “can,” “could,” “may,” “will” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements that we make. These forward-looking statements involve risks and uncertainties that could cause our actual results to differ materially from those in the forward-looking statements, including, without limitation: subsequent study or trial results and findings may contradict earlier study or trial results and findings, including with respect to the discussion of the TissueCypher® Barrett’s Esophagus test in this press release; actual application of our tests may not provide the aforementioned benefits to patients; and the risks set forth under the heading “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2022, and in our other filings with the SEC. The forward-looking statements are applicable only as of the date on which they are made, and we do not assume any obligation to update any forward-looking statements, except as may be required by law.

1. Khoshiwal AM, Frei NF, Pouw RE, et al. A tissue systems pathology test outperforms pathology review in risk stratifying patients with low-grade dysplasia. Gastroenterology. 2023. doi: https://doi.org/10.1053/j.gastro.2023.07.029