By Diagnostics World Staff
September 10, 2015 | This morning, Pathway Genomics of San Diego announced the launch of two liquid biopsy tests to detect cancer-related DNA mutations, including one that the company claims is the first liquid biopsy on the market for early detection of cancer in healthy patients. These tests extract free-floating DNA from small, non-invasive blood samples, and test it for genetic variants that are common markers for cancer. Traditionally, liquid biopsies are used to monitor the progress of patients undergoing cancer treatments: because they are less invasive and sample a greater variety of cancer cells than tissue biopsies, they are a useful tool for gauging whether the cancer is responding to therapy, and sometimes, whether it has developed new mutations that require a new treatment plan.
This is the model for Pathway’s new CancerIntercept Monitor test, which targets 96 known genetic variants across nine genes involved in multiple cancer types. In a nod to the likelihood that this test would be ordered repeatedly over the course of treatment, Pathway is offering a discount through a subscription service, which could reduce the cost per test to $299.
The second new test, CancerIntercept Detect, is instead geared toward healthy patients. Unlike other genetic tests for healthy individuals, this liquid biopsy is intended to screen for current cancers that are not yet symptomatic, rather than reporting a patient’s risk of developing cancer in the future. Aside from its intended use case, CancerIntercept Detect is broadly similar to CancerIntercept Monitor, covering the same genetic variants.
The choice to sell a genetic cancer diagnostic to healthy customers is likely to be controversial, raising the possibility of false positives and inviting closer scrutiny of the genetic variants Pathway has chosen to test for. Pathway is only offering this test to patients with some prior indication of risk for cancer, such as a family history of the disease, which should reduce the risk of misdiagnoses and overscreening.
Pathway has also chosen to make CancerIntercept Detect available for direct sale to patients online, through Pathway’s own network of ordering physicians, rather than requiring patients’ own physicians to order the test. This is an increasingly common model for providers of genetic diagnostics — in part, a response to low awareness of genetic testing options among many primary care doctors — but in nearly recapitulating the direct-to-consumer sales model that led the FDA to shut down 23andMe’s genetic tests in 2013, it raises many of the same questions about the role of the healthcare system in helping to interpret and guide the use of genetic information.
The new CancerIntercept tests will both be available as lab developed tests from Pathway’s CLIA-certified lab in San Diego.