Chief medical and technology officer, Cepheid, a Danaher company
After a 10-year tenure at Mayo Clinic—which included setting up its first polymerase chain reaction (PCR) laboratory—David Persing, M.D., Ph.D., headed into industry. His first stop? Corixa, a Seattle-based biotech working on immunotherapies for various diseases.
“It was a walk on the biotech wild side. If I’d known the true risk at the time, maybe I wouldn’t have done it,” Persing said.
But make the move he did, and he’s been in industry ever since. From there, he found his way to molecular diagnostics player Cepehid, which he joined in 2005, the day after GlaxoSmithKline sealed a $300 million deal to buy Corixa.
In his 15 years as Cepheid’s chief medical and technology officer, Persing has worked on tests for diseases caused by bacteria, like mycobacterium tuberculosis and MRSA, as well as those caused by viruses, including hepatitis, HIV, influenza and now, COVID-19.
In March, Cepheid’s test became the first point-of-care diagnostic for SARS-CoV-2, the virus that causes COVID-19, allowing doctors in hospitals, clinics and emergency rooms test a sample for the disease in about 45 minutes.
The test is built to run on Cepheid’s automated GeneXpert hardware, with more than 23,000 tabletop systems installed worldwide and more than 5,000 in the U.S., according to the company. It went through a “rapid development cycle” because it’s based on the company’s test for influenza and respiratory syncytial virus (RSV), which is designed to help doctors determine in less than an hour if they need to give a patient the antiviral Tamiflu. Cepheid earned an emergency FDA nod for the test just seven weeks after starting the project.
“We started within a few days of getting the sequences (of the coronavirus) and that led to the initiation of a formal project in February, including a pretty sizable team to adapt our Flu/RSV assay to detect SARS-CoV-2,” Persing said. “We had to take out our Flu/RSV primers and put in SARS-CoV-2 primers, but we left everything else the same. The same viral transport medium, the same nasal and nasopharyngeal swabs—they were all set up to adapt to SARS-CoV-2.”
It may sound like a piece of cake, but Cepheid encountered hiccups along the way, including reagents that didn’t quite do what the company wanted them to do, as well as those that “played badly” with other reagents.
“It was a huge challenge, but we made the right decision in doing it,” Persing said. “We have always been focused on getting the best possible sensitivity—we want to get reference lab sensitivity in a rapid on-demand, easy-to-use format. We really don’t want a test that is 80% sensitive, because we don’t want to admit somebody to the hospital who tested negative in the emergency room only to find out later that they were actually SARS-CoV-2 positive. That is a disaster.”
In midsummer, Cepheid realized the fall and its accompanying flu season might throw a wrench in the COVID-19 response.
“We were not sure what was going to happen with ‘CoV-2, but if it persisted, we were going to be faced with the dilemma of a respiratory virus season with co-circulating flu A, flu B, RSV and coronavirus, all of which can look clinically very similar,” Persing said.
The company created a diagnostic that would test for all four at the same time and return results in 36 minutes, to help doctors pick the right treatment for each patient. The test got an emergency OK from the FDA in late September.
Along the way, Cepheid partnered with Sherlock Biosciences, a company working on CRISPR-based molecular diagnostics whose quick COVID-19 test is also FDA-cleared. The duo is exploring if Sherlock’s CRISPR-based can work on Cepheid’s automated lab systems to potentially bring the former to many thousands of customers around the world.
Cepheid is working to “dramatically increase” its production capacity over the next year or so, so that everyone with its GeneXpert hardware can use the COVID-19 tests.
“We don’t think this is all going to vanish overnight. We think the need for testing will persist even after vaccines are available because of pockets of the population who refuse to be vaccinated, don’t respond to the vaccines, or won’t get a booster,” Persing said.
And it won’t stop at COVID-19. Its combination test is already designed to test for multiple regions of influenza A, allowing it to detect both current and future variants of the virus, including pandemic strains, like bird flu. It’s also designed to look for multiple segments of the new coronavirus so it’s pandemic-ready on both those fronts, Persing said.
The company is working to include coverage of all coronaviruses that can affect humans, from MERS and MERS-related viruses to other SARS viruses and seasonal coronaviruses, like the ones that cause the common cold.
“That’s sort of the next-generation cartridge for pandemic readiness for coronaviruses,” Persing said. Cepheid is also working on a pandemic readiness portfolio that includes a panel for hemorrhagic fever viruses like Ebola and a panel for tropical fever viruses, including Zika, dengue, malaria, Chikungunya and some bacteria.
It’s all part of preparing for SARS-CoV-3, or whatever causes the next pandemic. Because whatever happens with COVID-19, it won’t be the last pandemic we face.
“We feel obligated to build better pandemic readiness into the portfolio and be more able to respond quickly the next time this happens,” Persing said. “There are ways to do that—stockpiling reagents and materials, not having to wait for months to reach manufacturing capacity levels—and I think those are things we have to work on. There are different problems to solve, but I think they are approachable with better planning.”
Editor's note: This story has been updated to clarify details of Cepheid's partnership with Sherlock Biosciences.