Q & A About the NETest

Dr. Liu, one of our esteemed NET specialists in the U.S. has a Facebook page where he offers a Question and Answer session once a month. This month, he featured guest Nancy Teixeira, a registered RN who works with Wren Labs to discuss their proprietary NETTest. Questions were asked by moderator Chris Nashville.

1. What is WREN?
   Wren is a CLIA – approved clinical laboratory that is focused on diagnostic tests that improves the management of patients with neuroendocrine tumors. The first launched test, known as the NETest, has been validated in over 3,000 clinical samples. It can be used to monitor the biological behavior of neuroendocrine tumor disease. The company is based in Branford Connecticut and was established by clinicians and scientists from Yale University. It has been in existence for 3 years and focuses on clinical laboratory testing as well as performing research using advanced molecular diagnostic technologies. This is where blood samples are sent and analyzed.
   1. How long does it take to receive results back from a Wren test?
      Less than a week typically.
2. How Many Patients have done the WREN test?
   Over 3,500 research and clinical samples have been evaluated using the NETest. These include samples from NET patients as well as from other types of cancers. The information obtained from these studies have been published in 12 different peer-reviewed papers that have been scientifically and clinically accepted by the medical community. 
   (side note the test is used to TREND activity..one result does not give enough information to illustrate tumor activity.)
3. Is it approved by the FDA?
   Many laboratory-developed tests are not required to be approved by the FDA at this time and have CLIA oversight from the government’s CMS Division. CLIA certification is sufficient to meet today’s compliance regulations For example, Genomic Health’s Oncotype Dx, which is used to predict disease recurrence in women with breast cancer, is not FDA approved. This assay is commonly used by oncologists throughout the USA.
4. What are the costs? Does Health Insurance or Medicare or Medicaid cover it?
   A list price is currently being developed for the NETest. The price is currently being determined as well as the subsequent coverage through private health insurance, Medicare and Medicaid. It is Wren’s intention to assist NET patients in gaining access to the test with minimal or no out of pocket costs.
   1. Does the NETest take the place of the CgA test?
      CgA is serum based, the NETest is genomic and, based on recent literature, is far more specific than CgA. Check out the literature on the Wren website www.wrenlaboratories.com and see for yourself.
   2. Does Netest take the place of the CgA test?
      Yes. It completely replaces it in any clinical algorithm.
      [Input from Dr. Liu] Yeah, CgA just isn’t that helpful anymore. The problem is so many people take proton pump inhibitors.
5. Where can you get it? Can it be done outside of the United States? Do you have to go to a special place to have the test done?
   The NETest requires a physician-signed authorization (a test requisition) and a blood draw into specific tubes. A kit is provided which includes all the information for the physician, as well as tubes for the blood draw and a box to send the sample back to Wren Laboratories in Branford Connecticut. It is vital that the blood sample be sent on sufficient dry ice which can be easily purchased. It is also vital that the blood sample is put on dry ice soon after it is taken to preserve the circulating gene signature. Too little dry ice and the sample integrity will be compromised and will not be viable to test. The blood/sampling can be done at any physician’s office. Wren can provide physicians with a straightforward protocol for the collection and shipping of the sample. At the current time, samples cannot be drawn outside the USA.
6. What is a gene expression test? Can you explain what a gene signature is? Is there another disease that uses a similar test that we could compare to relate it to? Is it like the BRCA test?
   A gene expression test or gene expression profile (GEP) is a measurement of a set of different messenger RNAs that are produced by a tumor cell. When tumors exhibit some form of activity, for example respond to a somatostatin analog or start growing, they make or synthesize messenger RNAs. The RNA profile will change if a tumor starts to grow. It may decrease if somatostatin analogs are working. The NETest measures 51 different messenger RNAs that are linked to the tumor. If the expression increases, especially of messenger RNA associated with growth and proliferation, the signature increases. This will result in a high NETest. If the tumor is quiet and has little activity, the messenger RNA profile will be less and the NETest score will be lower. Surgery and drugs that are effective decrease the NETest. A high NETest indicates that the tumor is exhibiting biological activity or behavior. This approach is used in many other cancers. Oncotype Dx for example is a 21 marker gene expression test that is used in breast cancer. It is undertaken in tumor tissue and is used to predict (that is, show a risk) for breast cancer recurrence. A low score is associated with a low chance or risk of recurrence; a high score is linked to a high risk of breast cancer recurrence. Both the NETest and Oncotype Dx do exactly the same thing – they generate a risk profile – the major difference is the NETest does this in blood which makes it much easier to monitor how a tumor is responding. The BRCA test is a completely different kind of test. This identifies whether there is a genetic mutation which can predispose someone to breast cancer. It measures DNA not messenger RNA and is not linked to gene expression. A risk is linked to having the BRCA mutation but this is not as informative as measuring gene expression in the tumor.
7. I have heard Buzz about the NETest predicting the potential success of PRRT. How does it do this? What seems to be better to predict a favorable PRRT outcome…. having a high or low activity value?
   The NETest includes sets of genes that are linked to the biological behavior of the tumor. These include genes linked to proliferation, metabolism and growth signaling. A specific combination of these genes may predict PRRT efficacy. A recent paper identified this was accurate in 94% of cases. This is significantly better than any other current technique including somatostatin receptor imaging. Somatostatin receptor imaging can identify whether a tumor may respond to PRRT but its accuracy ranges from 40-60% – tumors may have the receptor but they do not respond to the therapy. In general (but not always), a higher NETest is associated with a more favorable PRRT outcome. It is the specific genes, however, which is the best predictor of a favorable outcome. Therefore, this is a different test from the NETest which is currently being marketed for patient monitoring. This PRRT-specific therapy prediction test is not currently available and will be launched in the first half of 2017.
8. Are the DNA markers measured by the NETest specific to malignant neuroendocrine cells or to tumors?
   A malignant neuroendocrine cell is the same as a tumor, the only difference is that a tumor comprises a large group of malignant cells. The NETest measures messenger RNA produced by malignant neuroendocrine cells irrespective of the size of the tumor. Small clusters of malignant neuroendocrine cells will produce mRNA that can be detected by the NETest. Such growths will not be detected by imaging. The NETest is calculated to be approximately 20,000x more sensitive than imaging for detecting malignancy. Please note however that no test is 100% accurate. The NETest has been validated in a number of different studies in more than 3,000 patients. These studies identified that a high score is >95% accurate for the presence of malignant neuroendocrine tumors.
9. Does a high active disease risk mean a high risk of metastases or a high tumor load or a high grade tumor?
   A high score is a measure of how biologically active the tumor is and provides a reflection of the behavior of the tumor. It does not tell that a tumor is high grade, just that the tumor is active. A high score is also not a measure of a high tumor load. Small tumors that are very biologically active, have high scores. A high score also does not mean there is a high risk of metastases. A high score provides a measure of tumor behavior and indicates a high risk of tumor growth or recurrence (after surgery) or that a drug is no longer effective. A good analogy may be cars on a freeway. From a distance they all look the same. However, there are fast cars and slow cars. A high NETest is similar to a fast car.
10. I have a very active 93.3 result yet my Ki-67 is less than 1(one). I am stable. For those that flag high but are stable what does the data mean?
    High scores and “stable” disease do indeed occur. In 95% of cases this is indicative that the tumor is biologically active and with time will be identified by imaging to have grown in size (imaging lags behind NETest results by 6months – 2-3 years). Regarding Ki-67, firstly, the NETest result does not directly correlate with this measurement. A Ki-67 measured 2 years is only a reflection of the growth of the tumor at the time. Tumors are remarkably heterogeneous and have hot-spots of activity within them. The Ki-67 value can only provide a once-off estimate. The NETest, because it measures genes in the blood, provides a real-time measurement of how the tumor is behaving. Low grade tumors can behave aggressively!
11. My NETEST result went from 26% to 46% if not now than when will this number cause action or a reaction from my oncologist? And what actions or reactions seem logical?
    The NETest is separated into three different categories – low, moderate, and high. A jump from 26 to 46% is a jump from a low to a moderate category. This is a significant biological event and suggests the tumor activity has increased. Your oncologist will typically make a clinical decision based on a number of factors including your current clinical status, changes in other biomarkers or alterations in imaging. A jump in the NETest is indicative that the tumor may no longer be responding as well as it has in the past to a therapy or, if you are not being treated, that it has started to grow again. Some clinicians may want to increase the dose of a medication or, more frequently, chose to do a follow-up image at an earlier time point. This is particularly relevant if the NETest is >80%. In such cases, there is a very high chance (>95%) that an image will detect tumor growth. A score of 46% is indicative that there are changes in the tumor; they are however likely to be demonstrated over a long time-frame. Every case is unique, and it will depend on the clinician as well as other medical information about you.
    1. NETest seems like it would be so valuable to see whether our Octreotide or other treatments are working or should be adjusted and much more accurate than the Octreoscan??
    2. Yes, that is its value and it is much more accurate than an octreotide scan…we’ve found NETs tumors prior to octreotide scans on several patients anywhere from 6 months to 2 years before tumors presented on scans!

Please see our video below featuring the presentation that Nancy Teixeira provided to the Northwoods NETS group in May 2014. You can also find a PDF of her presentation on our site, here.

Northwoods NETS