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DecisionDx-GBM

Thank you for your interest in the DecisionDx-GBM test.

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Welcome to Castle Biosciences, Inc.

If you, or someone for whom you care has been diagnosed with GBM, what you need most as you face the challenge is information. The more information with which you can arm yourself, the more educated your decisions can be. It is with this important fact in mind that you have come to explore DecisionDx-GBM.

What is DecisionDx-GBM?
INFORMATION + COLLABORATION + DECISION-MAKING

We at Castle believe the best way to approach a treatment plan begins with information gathering, followed by collaborative decision- making. Fortunately, today there is a way for a physician to know, based on the genetics of a patient's specific tumor, the likelihood of the tumor’s response to today's standard of care first line therapy. Standard of care consists of radiation treatment and chemotherapy using temozolomide. With the information provided by DecisionDx-GBM in hand, physicians and patients can make more informed decisions regarding immediate course of treatment. These decisions may range from the frequency of monitoring, to alternative experimental regimens, to quality of life management and to life planning.

DecisionDx-GBM is a proprietary multivariate molecular diagnostic test that probes tumor tissue for expression of certain genes. The nine genes (plus 3 control) that make up the assay have been shown in studies to be highly associated with outcome in GBM patients treated with standard therapy. Whether these genes are over or under-expressed and in what combination can give your physician a glimpse of how a certain tumor might behave in response to standard therapy alone. This information, in addition to other factors such as age and performance score then allows for a higher degree of individual prognosis and collaboration between physician and patient moving forward with an individualized treatment plan.

The DecisionDx-GBM test is run from a sample of tumor that was taken during surgery. There is no extra procedure or sample collection required. When your doctor orders the test, the appropriate sample will be requested from the lab where it is stored and sent to Castle Biosciences, Inc. for testing. A report will be generated and provided back to your doctor. This process takes approximately 2-3 weeks.

9 genes are analyzed in the lab and the sum total of their expression provides the DecisionDx-GBM Score. Based on this score, a patient falls into one of five categories (quintiles) which correspond to a percentage likelihood of 2 year survival and a median survival in months. This information appears on the Report Form provided to your physician.

How was DecisionDx-GBM developed?

Researchers at M. D. Anderson Cancer Center in Houston Texas studied GBM tissue from 4 different sets of patients from leading academic institutions across the United States. From this tissue, they were able to identify 200 genes that were strong individual association with survival in GBM patients.

They were then able to identify 38 genes that were common to all four sets of patients.

The possibility of false positive occurrence was ruled out and the 38 survival genes were then validated (results reproduced) in a separate set of patients. From those results, the 38 gene panel was further reduced to the 9 most robustly associated survival genes. Finally, another validation study was done in yet another set of patients.

How is DecisionDx-GBM paid for?

Castle Biosciences, Inc. will be working with Medicare, commercial insurance providers and, in some cases, your physician's institution to secure payment coverage for DecisionDx-GBM. Claims will be submitted on patient's behalf and followed through the system to payment. In instances where the test is not covered by insurance, or only partially covered, the balance of the payment will become the patient's responsibility. The Castle Patient Assistance Program is in place to help manage balances due and to provide assistance in cases of financial hardship.