OmniSeq Target™: How It Works & What You Need to Know

Thursday, November 5, 2015 - 2:54pm

Despite aggressive chemotherapy and radiation treatments, the malignant tumors in Sharon McCann’s lungs wouldn’t go away. By the time it was detected, the disease had spread to her lymph nodes, and surgery was not an option. Things looked bleak for the non-smoker, who was just 54 when she received her diagnosis.

But in the fall of 2013, she was given the chance to try a brand-new test, OmniSeq Target™. Developed at Roswell Park, the test would examine the DNA of McCann’s cancer cells to try to identify the molecules that were enabling the tumors to grow and thrive. Then the test would search for existing drugs called “targeted therapies” that were designed to target and disrupt just those molecules, without affecting healthy cells. McCann didn’t need to think twice.

A New Way to Treat Cancer

OmniSeq Target™ is a tool in the field of personalized medicine, which is revolutionizing cancer treatment. Think of personalized medicine as tailor-made therapy — the opposite of one-size-fits-all.

Traditionally, chemotherapy drugs have been prescribed for a patient based on the location of the patient’s tumor — in the breast, colon, or lungs, for example — and how far the cancer has progressed. But there’s a problem with that approach: the same drug, given to two different patients, might cause one person to go into remission while having no effect on the other person’s cancer. That’s because tumors are driven by individual genetic mutations, not just the organ in which they grow.

And because traditional chemotherapy drugs work by killing any rapidly-growing cells (such as cancer cells), they can wipe out both cancer cells and healthy cells that also grow rapidly. (That’s why chemo causes hair to fall out: hair cells, like cancer cells, grow very fast.)

Unlocking the Human Genome

Things began to change 12 years ago when an international team of scientists — including scientists from Roswell Park — first mapped the human genome. Thanks to their work, today it’s possible to identify many of the specific gene mutations that cause cancer cells to grow out of control, and to develop targeted therapies capable of blocking the abnormal genes. Targeted treatments are more likely to work and less likely to cause side effects.

Jeffrey Conroy, Roswell Park’s Director of Genomics Consortium Technologies, explains: “Instead of having broad-based, standard chemotherapy treatments with an unpredictable response, we can say, ‘This is the targeted therapy for your specific gene alteration, and the responses are much stronger and last longer.’”

Conroy says OmniSeq Target™ can identify changes (mutations) in 23 genes that are known to cause cancer and for which targeted therapies are available. Some of the therapies are already FDA-approved, while others are available through clinical trials. Fifteen of the 23 genes are associated with lung cancer; the others are linked variously to melanoma and cancers of the breast, colon, and lungs. Some overlap, causing more than one type of cancer.

The test represents a major leap in gene-sequencing technology, because it’s much faster than previous methods. It’s now possible to test for 23 genes at the same time and to get results in just a few days. Conroy says plans are in the works to expand it to a larger gene panel. “We want to keep the test up to date as we gain more knowledge about genes,” he says.

Who’s Eligible?

Since its introduction in August 2014, OmniSeq Target has been ordered for nearly 500 patients with late-stage non-small cell lung cancer, breast cancer, and melanoma, and there are plans to begin using it for other types of tumors as well.

Right now it’s available only to patients with stage IV disease, Conroy adds. But he and his colleagues hope that will change: “We really believe the test should be ordered as soon as a diagnosis is made, so the patient doesn’t go on a standard regimen of chemotherapy for a couple of years. We want patients to be tested right away so they can get targeted therapies that are available right now.”

For Sharon McCann, the promise of OmniSeq paid off. “Miraculously, I was blessed in two ways,” she says. “The test found my mutation (ROS1), which occurs in only 1% of lung cancer patients. Second, there was an oral targeted therapy, crizotinib (brand name Xalkori™), that was effective against the mutation.”

Eight weeks after she took the first pill, her lung tumors shrank by half, and today, two years later, “there is no sign of metastatic cancer.”

To learn more, listen in as three Roswell Park experts discuss OmniSeq Target and what it means for cancer patients.