New blood test helps detect cancer early

Print 11 September 2015
Gary Robbins / The San Diego Union-Tribune

A blood test that was scarcely heard of two years ago is quickly emerging as an alternative to the often painful practice of using needles or surgery to sample a patient’s tissues for signs of cancer.

Scientists from San Diego to Boston said the new “liquid biopsies” can easily detect potentially harmful tumor cells and mutated DNA traveling through the blood stream.

The tests show so much promise that analysts estimate the market for liquid biopsies could soar to $12 billion within a decade. It’s now a $100 million industry that’s being strongly driven by San Diego’s clutch of life-science companies.

On Thursday, Pathway Genomics will become the sixth local business to market or announce plans for a liquid biopsy test to aid patients or pharmaceutical companies.

Pathway is introducing CancerIntercept, which is designed for cancer patients and survivors. The product will also be offered to healthy people at risk for developing the disease.

“This is a highly sensitive test which may catch a lot of tumors,” said Jim Plante, founder and chief executive of Pathway. “It’s now also possible to monitor and guide treatment of previously diagnosed cancer patients.”

The excitement is pervasive, but it’s being tempered by a hard reality: Scientists and companies have yet to prove that liquid biopsies broadly enable doctors to significantly improve patient care. Further clinical evaluations are underway at places like UC San Diego’s Moores Cancer Center.

“We need to do more than just say cancer cells were found,” said Ivor Royston, a San Diego oncologist and managing member of Forward Ventures, a life-science venture capital company. “We need clinical studies that show that liquid biopsies can help doctors choose the right drug, at the right time, to stop cancer.”

He added: “This is an emerging technology, but it’s emerging fast. It’s nice to see San Diego taking a lead in the field.”

The boom was triggered during the past couple of years by major advances in identifying, profiling and analyzing genes, especially ones that mutate into cancer, a complex disease that kills about 565,000 Americans each year.

Tissue biopsies have long been used to search for tumors and track their development. Scientists and physicians describe it as a highly intrusive practice that sometimes can cause more harm than good. It’s not unusual for a person getting a lung biopsy to suffer a collapsed lung, for example.

Such biopsies also can fail to reveal all the ways in which DNA has mutated. In turn, that makes it difficult or impossible for doctors to provide patients with the precise drugs or therapies they need.

Earlier this year, UC San Diego cancer specialist Dr. Razelle Kurzrock told The Associated Press, “I’m really excited about all of this. I spent most of my life giving drugs that were useless to people” because there was no good way to tell who would benefit or to quickly determine when a medication wasn’t working.

The problem is further complicated in patients who suffer from advanced forms of cancer.

“The idea of poking or cutting into patients like that just isn’t viable,” said Dr. Murali Prahalad, president Epic Sciences of San Diego, whose liquid biopsy test is primarily used by researchers in the pharmaceutical industry. “We need a different way of doing things, and I think liquid biopsy is at the precipice of entering the clinical mainstream.”

Scientists like the new technology in part because it’s easy to use.

They simply draw a small amount of blood and examine it with a variety of diagnostic tools. Mostly, they look for intact tumor cells that circulate throughout the blood stream or pieces of DNA thrown out by tumors. Trovagene, another San Diego company, also looks for tumor DNA in urine samples.

These tests “take advantage of the recently discovered fact that tumors and cancerous cells can shed their genetic material into the circulating bloodstream,” UBS Securities said this year in a report for investors.

The diagnostics used to analyze the blood samples are extraordinarily sensitive — a point that Epic Sciences punches home on its website. There’s an image of cells overlaid with this message: “This is a blood sample from a cancer patient. It contains roughly 30 million cells. Of those, about five are cancer cells on their way to form tumors elsewhere in the body.”

While Epic Sciences targets the pharma industry, Pathway Genomics is more focused on patients, who can order its liquid biopsy online. If these consumers don’t have a doctor, the company will provide one to review their requests electronically. Pathway also will send technicians to customers’ homes or offices to draw the blood samples.

“We’d do it at a gas station if we had to,” said Ardy Arianpour, Pathway’s chief commercial officer.

Pathway said in a statement that its new test “detects mutations that are commonly associated with lung, breast, ovarian, colorectal cancers and melanoma.”

Such testing is meant to flag potential problems, not serve as an official diagnosis. It’s a step toward personalized medicine, the growing movement where patients are more directly involved in their health choices and medical care.

Hatim Husain, an assistant professor of medicine at the Moores Cancer Center, advised caution Wednesday while also expressing hope.

“There are a lot of expectations about liquid biopsy,” said Husain, who uses the tests. “It shows a lot of promise, (but) we don’t truly know where it will land.”

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