Castle Biosciences presented three abstracts on the validity of using its 31-Gene Expression Profile (GEP) Test for melanoma prognosis at the American Society of Clinical Oncology (ASCO) 2017 annual meeting June 2-6 in Chicago.
The GEP test, also known as the DecisionDx-Melamona test, uses 31 genes from primary melanoma tissue to provide an assessment of individual risk of melanoma recurrence and metastasis. By studying the individual molecular signature of each tumor, this test can help physicians form an informed opinion on the prognosis of individual melanoma cases.
The DecisionDx-Melamona test stratifies patients into one of two classes. If patients have a low five-year risk of metastasis, they are considered as class 1. If they are high risk, they are classified as class 2. To date, the GEP test has consistently shown accuracy in the prognosis of 690 patients in three multicenter studies. Results from all studies have supported a role for the DecisionDx-Melamona test as a complement to traditional staging methods.
The first abstract, “Interim Analysis of Survival Outcomes in a Prospective Multicenter Cohort Evaluating a Prognostic 31-Gene Expression Profile (GEP) Test for Melanoma,” demonstrated that using the DecisionDx-Melanoma test accurately predicted metastasis and survival in stage 3 melanoma patients in the INTEGRATE trial (NCT02355574).
Significantly different recurrence rates were observed for class 1 and class 2 patients. In addition, 83 percent of patients who developed metastases were classified as class 2, compared to 50 percent of patients who had a positive sentinel lymph node exam, one of the current conventional methods to determine risk of metastasis.
“This prospective, multicenter study adds to the growing body of evidence that the DecisionDx-Melanoma test produces consistent, clinically meaningful results,” study co-investigator Eddy C. Hsueh, MD, professor and director, St. Louis University Hospital, said in a press release. “The alignment of these results with previous studies shows that the DecisionDx-Melanoma test provides accurate, independent prognostic information across multiple practice settings.”
The second abstract, titled “Performance of a 31-gene expression profile (GEP) test for metastatic risk prediction in cutaneous melanomas (CM) of the head & neck,” demonstrated that the DecisionDx-Melanoma test could accurately identify the low- and high-risk patients with cutaneous melanoma of the head and neck region included in the EXPAND trial (NCT02355587).
Currently, the most accurate staging tool for determining the risk of metastasis in this specific tumor is whether the patient has a positive SLN (sentinel lymph node) biopsy. However, most patients who eventually develop metastasis are SLN-negative, so a biopsy is not a reliable prognostic text. Results from this study demonstrated that the GEP test could enhance the staging of this tumor and help accurately predict the risk of metastasis and survival.
The final abstract, “Interim analysis of survival outcomes in a prospective cohort evaluating a prognostic 31-gene expression profile (GEP) test for melanoma,” confirmed that the DecisionDx-Melamona test can accurately provide prognostic information that corroborates with those predicted by the current standards of staging. The test also significantly increases the ability to identify high-risk cutaneous melanoma patients, and analysis results confirm the association between the GEP class result and the outcome.
“It is important to identify early stage patients with melanoma who are at an increased risk of recurrence so that appropriate surveillance can be provided,” said study co-investigator Kelly M. McMasters, an MD and PhD at the University of Louisville.
“The results from this interim analysis confirming the association of the DecisionDx-Melanoma class with patient outcome align with my experience in clinical practice showing that assessing tumor biology can provide important, clinically impactful prognostic information,” McMasters said.