• New data shared in a poster presentation during the 19th European Association of Dermato-Oncology (EADO) Congress

FRIENDSWOOD, Texas / Apr 25, 2023 / Business Wire / Castle Biosciences, Inc. (Nasdaq: CSTL), a company improving health through innovative tests that guide patient care, today announced new data showing DecisionDx^®-Melanoma can improve risk stratification over American Joint Committee on Cancer (AJCC) staging alone in patients with stage I cutaneous melanoma (CM). DecisionDx-Melanoma uses a patient’s tumor biology to provide the patient’s personalized risk of recurrence and metastasis, while AJCC staging is based on the clinical and pathologic risk factors of a patient’s melanoma tumor.

“Patients with stage I cutaneous melanoma are considered to have a lower risk of recurrence and melanoma-specific mortality; however, due to the large number of patients diagnosed with stage I disease, this patient group accounts for the largest number of deaths from melanoma,” said Sebastian Podlipnik, M.D., Department of Dermatology, Hospital Clinic of Barcelona, Spain. “As the study showed, DecisionDx-Melanoma provides more precise risk stratification over staging alone to better predict which patients have a low risk of experiencing a poor outcome and those with more aggressive tumor biology who may benefit from increased clinical surveillance.”

The data were presented at the 19th European Association of Dermato-Oncology (EADO) Congress, held in Rome, Italy, in a poster titled, “The 31-gene expression profile outperforms AJCC in stratifying risk of recurrence in patients with stage I cutaneous melanoma.” In the study, DecisionDx-Melanoma provided significant and independent risk stratification of patients with stage I CM. Additionally, as reported in the study, the test added valuable prognostic information to AJCC staging to better stratify recurrence-free survival (RFS) and melanoma-specific survival (MSS) among patients with stage I CM.

Importantly, the data demonstrate that patients with AJCC stage I CM who had a high-risk (Class 2B) DecisionDx-Melanoma test result were 5.4 times more likely to die from melanoma compared to patients staged as IB according to AJCC staging. The results of the study support the use of DecisionDx-Melanoma to guide better risk-aligned care in patients considered low risk by staging by identifying high-risk patients who may be missed using only AJCC staging criteria.

About DecisionDx^®-Melanoma

DecisionDx-Melanoma is a gene expression profile risk stratification test. It is designed to inform two clinical questions in the management of cutaneous melanoma: a patient’s individual risk of sentinel lymph node (SLN) positivity and a patient's personal risk of melanoma recurrence and/or metastasis. By integrating tumor biology with clinical and pathologic factors using a validated proprietary algorithm, DecisionDx-Melanoma is designed to provide a comprehensive and clinically actionable result to guide risk-aligned patient care. DecisionDx-Melanoma has been shown to be associated with improved patient survival and has been studied in more than 10,000 patient samples. DecisionDx-Melanoma’s clinical value is supported by more than 40 peer-reviewed and published studies, providing confidence in disease management plans that incorporate the test’s results. Through Dec. 31, 2022, DecisionDx-Melanoma has been ordered 120,287 times for patients diagnosed with cutaneous melanoma. 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, 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 results of the study reported in this press release, the ability of DecisionDx-Melanoma to guide better risk-aligned care in patients considered low risk by staging, and the potential benefit to patients from increased clinical surveillance resulting from a DecisionDx-Melanoma test result. The words “believe,” “can,” “potential,” “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 or may not support the results obtained in this study, including with respect to the discussion of DecisionDx-Melanoma 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 Quarterly 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.