Brad Perkins, MD: New Data on Test Which Helped Identify Pneumonia-Causing Pathogens

When a new type of test for pathogens comes into existence, the question becomes how it may be implemented to detect illnesses that affect large numbers of patients.

In this interview with the HCPLive editorial team, Brad Perkins, MD, MBA, spoke on recent data from a landmark study regarding a liquid biopsy test for infectious diseases known as the Karius Test.

Perkins serves as Chief Medical Officer for Karius, Inc., and he was formerly a top Centers for Disease Control (CDC) official who helped to lead the post-September 11 anthrax bioterrorism investigation.

“What's different about the Karius Test, is, instead of having to apply all these individual tests in a serial way,” he said. “We have a single testing format that is capable of identifying all human pathogens, or all human causes of infectious diseases. Right now, it's focused only on DNA-based pathogens, which are actually the most common human causes of infectious diseases. But very shortly, we'll be able to capture RNA-based pathogens as well, using this technique.”

Perkins explained that the critical difference that allows the test to do this is that those implementing it focus on a new clinical analyte which is called microbial cell-free DNA (mcfDNA).

“So, instead of looking for a single infectious disease, cause, or etiology, we look for this analyte,” Perkins explained. “These fragments of DNA, and in the near future RNA, that are floating in the bloodstream, as a result of replication of these infectious agents by identifying the signal and preparing specimens in ways that amplifies the microbial signature and suppresses the human signal, we can do what's called meta-genomic sequencing.”

Perkins explained that then testers can sequence everything in a blood sample and then implement a database to match the sequence of that microbial cell free DNA in the blood sample to reference genomes that match individual infectious diseases.

He also connected this research to recent news in China regarding an apparent outbreak of pneumonia.

“The reason it's so relevant to the situation in China, to the recognition of SARS‑CoV‑2, is that this new approach to infectious disease testing can be applied at large scale to give us an extraordinary improvement in situational awareness,” Perkins said.

Later, Perkins was asked about the recent article published that had described the use of the Karius Test In immunocompromised patients with pneumonia.

“The design of this project was intended to directly compare the performance of the Karius Test as a single blood test to all other usual care that's used today, including not only routine, non-invasive tests using blood, but also using invasive tests,” Perkins explained.

Perkins noted that with almost 270 participants included in the research, these subjects at the time of enrollment underwent a blood sample for the Karius Test. These individuals also underwent bronchoscopy and other routine testing for pneumonia at 10 major cancer centers in the United States.

“These are leading centers with, sort of, best practices in diagnosis of pneumonia in these patients,” Perkins said. “And there were some extraordinary findings that we published. Probably the most important, particularly for the patients and the families of these patients, was we demonstrated the seriousness of these infections. So this was an observational trial. We did not share the results of the Karius Tests with the clinical team taking care of these patients. So they received usual care with usual testing only. And with that care, a little bit over a quarter of the patients died during their admission for pneumonia. That tells you how serious of a threat this infection is in this highly immunocompromised population.”

For further information on Perkins’ data, view the full interview posted above.

The quotes included in this summary were edited for clarity.