• Data from patient simulation study to be presented at ESGE (European Society of Gastrointestinal Endoscopy) Days 2023

FRIENDSWOOD, Texas / Apr 20, 2023 / Business Wire / Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced new data from a patient simulation study which showed that, compared to pathology alone, TissueCypher® Barrett’s Esophagus test results may significantly increase the likelihood of appropriate management decisions for Barrett’s esophagus (BE) patients with low-grade dysplasia (LGD) according to their risk of progressing to esophageal cancer.

Overall, the study results showed that TissueCypher standardized the management of BE cases with LGD to improve health outcomes by potentially:

• Reducing the incidence and mortality of esophageal adenocarcinoma for high- and intermediate-risk patients through shorter surveillance intervals and/or endoscopic eradication therapy (EET).
• Reducing unnecessary use of EET and endoscopies for low-risk patients.

“Clinical guidelines recommend expert pathology review for a diagnosis of Barrett’s esophagus with low-grade dysplasia; however, expert review is highly variable and is not easily accessible for many patients,” said Jacques Bergman, M.D., Ph.D., of Amsterdam University Medical Centers in Amsterdam, the Netherlands, one of the largest centers of esophageal and gastric cancer in Europe. “TissueCypher provides a potential solution to help address these challenges by providing objective and independent information that can help guide appropriate treatment and surveillance strategies for patients according to their biologic risk of progressing to more advanced dysplasia or esophageal cancer.”

In the patient simulation study, the percentage of cases with 100% likelihood of receiving appropriate management per their known progression outcome increased from 9% with a pathologist diagnosis alone to 31.8% when TissueCypher test results were considered in conjunction with pathology; this further increased to 77.3% when TissueCypher test results were used alone. Overall, the study data showed that, compared to pathology alone, using TissueCypher test results to guide management decisions significantly increased the likelihood that BE patients with LGD could receive appropriate management per their known outcome (p=0.0002), which supports use of the test to help standardize the management of BE patients to potentially improve their overall care and health outcomes.

Details of the study will be shared in an oral presentation during the upcoming ESGE Days 2023 meeting, presented by the European Society of Gastrointestinal Endoscopy, being held April 20-22 in Dublin, Ireland. The presentation will be given by lead study author Amir Khoshiwal, M.D., from the research team of Dr. Bergman. Presentation details are as follows:

• Presentation title: A Tissue Systems Pathology Test Has Significant Clinical Utility to Standardize Management Leading to Improved Health Outcomes for Barrett’s Esophagus Patients with Low-Grade Dysplasia
• Session: Barrett's Esophagus: Taking Patient Care to the Next Level
• Day and Time: Saturday, April 22, at 10:50 a.m. GMT (Irish local time)
• Location: Liffey Meeting Room 2

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). TissueCypher is indicated for use in patients with endoscopic biopsy confirmed BE that is graded non-dysplastic (ND), indefinite for dysplasia (IND) or low-grade dysplasia (LGD); its clinical performance has been supported by nine peer-reviewed publications of BE progressor patients with leading clinical centers around the world. The TissueCypher Barrett’s Esophagus test is a proprietary Laboratory Developed Test with its own unique CPT PLA code (0108U). Additionally, the test received Advanced Diagnostic Laboratory Test (ADLT) status from the Centers for Medicare & Medicaid Services (CMS) in March 2022 and was recognized by the American Gastroenterological Association (AGA) in their 2022 Clinical Practice Update as a tool that may be used to risk-stratify patients with NDBE.

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, Twitter and Instagram.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-SCC, MyPath Melanoma, DiffDx-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: the potential of TissueCypher test results to (i) significantly improve the management of LGD in patients with BE compared to pathology alone, as well as improve health outcomes; (ii) standardize the management of BE patients with LGD to improve health outcomes by helping ensure that patients at a high risk of progression receive earlier interventions and by potentially reducing unnecessary use of EET and endoscopies for lower risk patients; (iii) reduce inconsistencies in management decisions for BE patients with LGD; and (iv) reduce the incidence and mortality of esophageal cancer and the use of unnecessary clinical treatments, when appropriate. The words “can,” “may,” “potential” 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 or may not support the results shown in this study, including with respect to the discussion of TissueCypher 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.