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Minnesota-developed test aims to measure effectiveness of breast cancer treatment

The test, named HERTEST, was created by scientists at Martell Diagnostic, a Roseville-based med-tech company.

With HERTEST readings, it may be possible one day for oncologists to monitor and observe women for signs of reoccurring breast cancer similar to the way they monitor men for prostate cancer using a PSA test.
With HERTEST readings, it may be possible one day for oncologists to monitor and observe women for signs of reoccurring breast cancer similar to the way they monitor men for prostate cancer using a PSA test.
REUTERS/Jim Bourg

A new test developed by a Minnesota company promises to give women undergoing breast cancer treatment and their physicians a noninvasive way to monitor disease progression.

The test, named HERTEST, was created by scientists at Martell Diagnostic, a Roseville-based med-tech company. It is a blood test that can monitor the effectiveness of cancer medications and detect recurrences of tumors, reducing the need for invasive procedures like biopsies.

In the regular course of breast cancer treatment, patients typically undergo chemotherapy, radiation and surgery, said Michelle Edwards, Martell Diagnostic’s CEO. Patients generally do not know if their cancer is responding to interventions until they undergo imaging or a surgical biopsy after the treatment course has been completed.

For many patients, this liminal time is difficult, Edwards said.

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“Waiting to see the results until the end of a course of therapy is a really stressful,” she said. “I know this well because I have a loved one going through breast cancer treatment right now.”

Michelle Edwards
Michelle Edwards
With HERTEST, Edwards explained, patients and their physicians can measure whether therapies are working by following the level of HER2, a protein that rises in direct relationship to disease activity, in the patient’s blood.

Finding that a patient’s cancer is not responding to treatment midcourse could give physicians a chance to reevaluate their approach without losing valuable time, she said. “Learning if something is working in real time is what a patient and their physician would want.”

Potential for distanced monitoring

Mark Greene, M.D., Ph.D., the John Eckman Professor of Medical Science at the University of Pennsylvania, is Martell Diagnostic’s scientific adviser. He said that the HERTEST provides physicians with a more distanced way to keep tabs on tumor progression.

“Once you’ve had surgery, once you’ve removed the tumor, there’s no really good way to find out if the cancer has reoccurred,” Greene said, explaining that in 1981, he was the first to describe the HER2 protein, eventually developing the antibody antagonists needed to make the cancer-fighting drug Herceptin: “This test provides a way to monitor these progressions.”

Mark Greene
Mark Greene
When a woman develops a mass in her breast, Greene explained, “Typically there are two ways to define what it is. One way is to cut into the lesion and do a biopsy and check for the presence of the gene. That is what is done for most women in America.” After the mass is removed, Greene said, “There is not a good way to see if a patient still has cancer, because you’ve taken out the tumor.” Because it can measure HER2 levels in a patient’s blood, he added, “The HERTEST allows you to do just that.”

Edwards said that with HERTEST readings, it may be possible one day for oncologists to monitor and observe women for signs of reoccurring breast cancer similar to the way they monitor men for prostate cancer using a PSA test in an approach commonly known as “watchful waiting.”

Because it tends to be a more aggressive disease, patients with breast cancer would need to be monitored more closely than those with prostate cancer, Edwards cautioned, but the HERTEST could be taken on a regular basis to determine if the patient needed more assertive treatment.

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For a woman with managed breast cancer, Edwards said, “We hope that HERTEST could be used, say quarterly or monthly, to monitor and make sure that everything is staying under control. With a blood-based test like this, the patient and physician could quickly see if the cancer was reoccurring and respond appropriately.”

Because the test can be performed mid-cancer treatment, Edwards said, physicians can use it to measure the efficacy of their treatment.

With HERTEST, Edwards said, “These biomarkers can give you a clue whether your treatment is working real time. If it is not working, your physician can take a closer look at your therapy and try something else. This is a significant advancement in cancer care that could change lives.”

Potential uses worldwide

Today, when a patient takes a HERTEST, their blood sample is sent to Martell Diagnostic’s lab for processing. Results are read and returned to the patient and physician. Looking for a test that delivers rapid results without requiring lab work, the company is developing a new way to interpret the tests.

“We got involved with a company that develops lateral flow test,” Edwards said. In a lateral flow test, test results from a finger-stick blood test wick across specially prepped paper to display results, in an approach similar to a commercial pregnancy test.

“We’ve now got a really basic version of HERTEST that does that,” Edwards explained. While she said that this approach to reporting results “doesn’t have that much use in the U.S.,” where patients have ready access to blood draws and laboratories, it will be helpful in the developing world, where access to testing sites is often limited: “Around the world there are many cases where a patient’s HER2-positive breast cancer could be treated if there was a cheap and easy-to-use test like this.”

In some countries in the developing world, she said, breast cancer patients and their physicians have less access to diagnostic tools like scanning equipment and labs that can accurately report the results of biopsies.

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The potential created by a finger-stick blood test that can accurately measure HER2 protein levels would be enormous, Greene said. “You have to think beyond America to countries where it is very difficult to do biopsies.”

With a goal of making HERTEST available to women fighting breast cancer in countries with limited access to medical technology, Edwards said that Martell has formed a partnership with a cancer clinic in Tanzania to test the use of the lateral-flow results. “This is an important collaboration,” she said. “This test could be a good tool for them. In the clinic setting in Tanzania, they’d to a finger stick and have a drop of blood would be applied to the end of the test.”

Often, she said, patients in Tanzania who are diagnosed with breast cancer have little information about their kind of cancer or the best approach to treat it. “They don’t have enough pathologists or labs or money to do more sophisticated testing. With this collaboration, physicians there could give someone a HERTEST. If the bar was dark enough, that tells the physician if the patient is a good candidate for targeted therapy.”

Available to the public

Patients or physicians can now order HERTEST on Martell Diagnostic’s website and have it  delivered. If a patient is interested in using HERTEST, Edwards said, “They should talk to their doctor about it first.” Though the company has had cancer patients approach them to purchase the test on their own, to do the test, they’d need to go to a lab facility and have a technician draw a vial of blood: “Our lab would then do the testing and we’d mail the results back.”

While she supports the idea that women with breast cancer have the authority to take their therapy into their own hands, Edwards insists that the best route would be to work in close collaboration with a physician.

“With something like cancer, you can and should work with your oncologist,” Edwards said. ”They have to be intensely involved in your therapy.” With the knowledge gained from HERTEST, individual women, in partnership with their physicians, can take control of their cancer treatment: “My hope is that all women with breast cancer will get a more live look at how their therapy is going. We believe that HERTEST is a good tool for that.”

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Greene and Edwards believe that HERTEST will eventually gain acceptance among oncologists, but the test is still so new that few besides those who have directly consulted with the company are aware of it. In the process of reporting this story, MinnPost reached out to several Twin Cities cancer researchers and oncologists, including the University of Minnesota Medical School, Virginia Piper Breast Center and Hennepin Healthcare, but none felt qualified to comment.

Edwards said that she’s confident that the test will soon gain acceptance in the larger medical community.

“All oncologists want better information on how to treat their patients’ cancer,” she said. “This test can give them that.”