Protein expression blood test targets lung nodules

SEATTLE—Integrated Diagnostics (Indi) is betting that the introduction of Xpresys Lung, a protein expression blood test, has strong potential for helping physicians diagnose more lung nodules as likely benign, thereby increasing the number of patients who can confidently choose serial CT scans of their nodules (also known as active surveillance) instead of invasive procedures like surgery and biopsy that carry significant risks and costs.

Xpresys Lung is designed only to assist physicians in identifying lung nodules likely to be benign, and is not intended to assist physicians with the identification of lung cancer.

The non-invasive blood test measures the relative abundance of proteins from multiple disease pathways associated with lung cancer, using a highly sensitive analytic technique called multiple reaction monitoring mass spectroscopy (MRM-mass spec).

“MRM-mass spec is a highly accurate analytic technique that allows Xpresys Lung to specifically measure the levels of 11 proteins related to multiple lung cancer disease pathways,” notes Indi’s CEO, Dr. Albert A. Luderer. “Mass spectroscopy has several advantages,” he continues, “including the ability to measure multiple proteins at once. This allowed Indi to use the same technology platform during discovery, validation and now in our commercial CLIA lab. By maintaining the same platform, we were able to avoid ‘loss in translation,’ which happens when researchers are unable to replicate results when they switch from their research platform to a new commercial platform.”

A retrospective validation study suggests that the test could allow physicians to recommend active surveillance to more of their patients. This laboratory-based analytical method offers objective molecular information about lung nodules (round lesions up to 30 mm in size) that physicians may use in addition to traditional independent predictors for assessing lung nodules, such as age, smoking history, nodule size and location. Data from two studies supporting the technology behind Xpresys Lung were published in Science Translational Medicine on Oct. 16.

“At Indi, our hope is that Xpresys Lung can provide objective molecular information about patients’ lung nodules that will allow their physician to more frequently recommend serial CT scan follow-up, thereby avoiding costly and risky invasive procedures,” said Dr. Kenneth C. Fang, chief medical officer at Indi and a board-certified pulmonologist. “Every year millions of patients have CT scans that find one or more lung nodules—each one of these raises concern about cancer. Most turn out to be benign. But, identifying which nodules are at low probability for lung cancer is difficult. We believe Xpresys Lung may play an important role in reducing this diagnostic dilemma.”

Active surveillance is a lung nodule management process that includes monitoring of a patient’s nodules using CT scans at regular intervals, generally over the course of two years. Patients receive regular check-ups and typically only undergo more invasive procedures if their nodules grow. Among patients with nodules 8 mm to 30 mm in size, it is estimated that as many as 80 percent turn out to be benign. Among patients with nodules who undergo surgical procedures, as many as 34 percent end up with benign pathological findings. Those figures suggest that many patients receive procedures that may be unnecessary and that they may be better served by active surveillance.

“Instead of following the traditional diagnostic strategy of seeking to identify disease, the approach we took with Indi’s first test is to help physicians identify patients whose lung nodules are likely to be benign,” states Luderer. “We believe the identification of a protein blood signature that may help identify likely benign lung nodules is an important step in helping physicians and their patients avoid unnecessary diagnostic procedures, thereby reducing costs, risks and the personal toll that comes with the diagnosis of a serious disease like lung cancer.”

Indi is a spinout of the Institute for Systems Biology in Seattle, Luderer explains. The company was founded to translate Lee Hood’s research on organ-specific blood proteins and the ability to interrogate disturbed biological networks associated with a specific pathology, into blood-based diagnostic tools that help physicians diagnose and manage complex diseases. Hood and Indi both believe that blood is the body’s window to health and disease.