Newly Published Independent, Prospective Study Reinforces Prognostic Accuracy of DecisionDx-Melanoma in Cutaneous Melanoma

Castle Biosciences, Inc., a skin cancer diagnostics company providing personalized genomic information to improve cancer management decisions, today announced publication of an independent, prospective study of 159 patients with cutaneous melanoma showing that the DecisionDx-Melanoma gene expression profile (GEP) test accurately identified risk of melanoma recurrence independent of other prognostic factors such as Breslow thickness and sentinel lymph node biopsy (SLNB) result. The study was published in the journal Cancer Medicine and is consistent with previously published prospective and retrospective studies demonstrating the high performance of DecisionDx-Melanoma to predict outcomes, supporting its clinical value to inform patient management decisions.

In this prospective study with 3.5 years of overall follow up, DecisionDx-Melanoma was shown to be an independent prognostic factor that is additive to traditional staging factors, commented lead study investigator Eddy C. Hsueh, M.D., Professor and Director, Division of General Surgery, St. Louis University Hospital. Accurate risk assessment for cutaneous melanoma is increasingly important to inform patient management decisions including surveillance, follow-up and potential adjuvant therapy consideration.

Patients from this academic center who were diagnosed with cutaneous melanoma received both the DecisionDx-Melanoma test and SLNB as part of their initial work-up. The median tumor Breslow thickness was 1.4 mm and 24% of patients had ulcerated tumors. Sixty percent of patients had American Joint Committee on Cancer (AJCC) Stage I melanoma, 25% had Stage II melanoma and 15% had Stage III melanoma. Patients were followed at regular intervals with an overall median follow-up time of 3.7 years for patients who did not experience an event.

Key Results:

  • 117 patients had a Class 1 (low risk) DecisionDx-Melanoma test result; 42 patients had a Class 2 (high risk) test result.
  • 139 patients had a negative SLNB result; 20 patients had a positive SLNB result.
  • 29 patients experienced a recurrence. Of those who experienced recurrence, 23 (79%) were classified as high risk (Class 2) by DecisionDx-Melanoma. Ten patients who experienced recurrence (34%) had a positive SLNB result and 19 (66%) had a negative SLNB result. Nine of 10 patients who were high risk by both assessments (positive SLNB result and Class 2 result) experienced recurrence.
  • The negative predictive value (NPV) of a Class 1 result was 95% for recurrence and 99% for distant metastasis. Sensitivity of a Class 2 result was 79% for recurrence and 94% for distant metastasis.
  • The 3-year recurrence-free survival (RFS) rate for patients with a Class 1 result was 96.6%, significantly higher than the RFS of 47.4% for those with a Class 2 result (p<0.0001).
  • The 3-year distant metastasis-free survival (DMFS) rate for patients with a Class 1 result was 99.1%, significantly higher than the DMFS of 64.1% for those with a Class 2 result (p<0.0001).
  • DecisionDx-Melanoma was the most significant predictor of recurrence (Class 2 hazard ratio=9.2, p=0.0001) and distant metastasis (Class 2 hazard ratio=19.0, p=0.009) risk in multivariate analysis comparing to age, Breslow thickness, ulceration and SLNB result.

The full published study results can be accessed at the journals website.

About DecisionDx-Melanoma

DecisionDx-Melanoma is a gene expression profile test that uses an individual patients tumor biology to predict individual risk of cutaneous melanoma metastasis or recurrence, as well as sentinel lymph node positivity, independent of traditional staging factors and has been studied in over 2,900 patients. Using tissue from the primary melanoma, the test measures the expression of 31 genes. The test has been validated in three multicenter studies that have included 690 patients and have demonstrated consistent results. Performance has also been confirmed in five prospective studies including over 780 patients. The consistent high performance and accuracy demonstrated in these studies, which combined have included over 1,470 patients, provides confidence in disease management plans that incorporate DecisionDx-Melanoma test results.

Prediction of the likelihood of sentinel lymph node positivity has also been validated in two prospective multicenter study cohorts that included over 1,400 patients. Impact on patient management plans for one of every two patients tested has been demonstrated in multicenter and single-center studies. More information about the test and disease can be found at www.SkinMelanoma.com.

About Castle Biosciences

Castle Biosciences is a skin cancer diagnostics company dedicated to helping patients and their physicians make more informed decisions about treatment and follow up care based on the individual molecular signature of the patients tumor. The Company currently offers tests for patients with cutaneous melanoma (DecisionDx-Melanoma, DecisionDx-CMSeq; www.SkinMelanoma.com) and uveal melanoma (DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq; www.MyUvealMelanoma.com), with programs in development for other underserved cancers, the most advanced of which is focused on patients with cutaneous squamous cell carcinoma. Castle Biosciences is based in Friendswood, Texas (Houston), and has laboratory operations in Phoenix, Arizona. More information can be found at www.CastleBiosciences.com.

DecisionDx-Melanoma, DecisionDx-CMSeq, DecisionDx-UM, DecisionDx-PRAME and DecisionDx-UMSeq are the trademarks of Castle Biosciences, Inc. Any other trademarks are the property of their respective owners.

Derek Maetzold, President and CEO
866-788-9007
[email protected]