Consumer blood test to detect cancer hits market amid skepticism

(Bloomberg) — Biotechnology startup Pathway Genomics Corp. is introducing the first “liquid biopsy” tests designed to detect cancer-associated mutations in the blood of healthy people who are at high risk of developing tumors.

While doctors are enthusiastic about the potential of liquid biopsies as a low-cost, non-invasive alternative to traditional tissue biopsies, they say more evidence is needed to validate the tests’ sensitivity before being offered to consumers, especially those without disease.

Pathway, a closely held firm backed by investors including International Business Machines Corp. and venture capital firm Founders Fund, is offering its CancerIntercept Detect test for $699, according to chief executive officer Jim Plante. The price tag drops to $299 if the consumer signs up to be tested once a quarter.

“The cost is a big advantage because a liquid biopsy could be one-10th or one-20th the cost of an invasive biopsy,” Plante said. “There’s a lot of value here for the patient and consumer.”

DNA fragments

Liquid biopsies are gaining attention in the biotech sector. The tests screen the blood for tiny fragments of genetic material released by tumors, known as circulating tumor DNA. Such tests have only recently become available as gene sequencing has become more affordable and the technology has improved so much that it can detect just a few molecules of errant DNA in a vial of blood.

Guardant Health Inc., a closely held company backed by investors including Khosla Ventures and Sequoia Capital, was the first to introduce a test to monitor patients already diagnosed with cancer. Pathway is also selling a separate test for active patients, which will cost $999 for a single draw, according to Plante.

Pathway, based in San Diego, is joining a wave of health startups offering tests for healthy consumers at affordable prices, often bypassing insurance coverage. Some, such as Color Genomics Inc. and 23andMe Inc., tell consumers their genetic susceptibility to certain diseases. Others, like Theranos Inc., are encouraging consumers to keep track of general fitness through regular monitoring of basic metrics such as cholesterol.

Studies needed

Some doctors are cautious about the liquid biopsies. There have been no long-term studies done on their ability to detect early-stage cancer in healthy individuals, said Keith Stewart, head of the Mayo Clinic’s Center for Individualized Medicine.