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Cambridge biotech’s virus test using CRISPR gene editing OK’d for crisis

Sherlock Biosciences’s radically different kind of lab test promises results in an hour

This 2020 electron microscope image, made available by the Centers for Disease Control and Prevention, shows the spherical particles of the new coronavirus, in blue.Hannah A. Bullock, Azaibi Tamin/Associated Press

A Cambridge biotech startup received emergency clearance Thursday for a faster and radically different laboratory test to diagnose COVID-19, a kit the company says can give results within an hour.

The Food and Drug Administration provided an “emergency use authorization” for the test made by Sherlock Biosciences. It relies on the revolutionary genome-editing tool CRISPR, which edits DNA and has the potential to treat a vast array of diseases but had yet to win FDA approval for any product. The tool was repurposed to create a diagnostic test.

Rahul Dhanda, cofounder and chief executive of Sherlock, said the test will be made by a “large-scale maufacturer.” Dhanda said he couldn’t identify the company yet because of a confidentiality agreement but hopes to announce it within a week or two.


Initially, Sherlock plans to sell enough tests for hospital laboratories to check at least 10,000 patients a week for the coronavirus. The company could ultimately do a million tests a week if there’s enough demand, he said.

“We are committed to providing this initial wave of testing kits to physicians, laboratory experts, and researchers worldwide to enable them to assist front-line workers leading the charge against this pandemic," he said.

A number of public health experts have said the United States isn’t doing nearly enough testing to lift the lockdown that has been imposed on the nation to prevent the spread of COVID-19.

On average, nearly 248,000 tests daily have been conducted nationwide in the last seven days, according to the nonprofit Covid Tracking Project. Harvard’s Global Health Institute, a prominent research group, says the United States should be doing more than 900,000 a day, according to an NPR report on Thursday published in partnership with the institute.

Standard COVID-19 tests used since the epidemic erupted are PCR, or polymerase chain reaction, tests. Patients typically provide a nasal or throat swab for analysis, and it usually takes several hours if not days to get results.


Sherlock’s test also relies on a swab, but works by programming a molecule to detect the presence of a specific genetic signature ― in this case, the signature for the coronavirus. When the signature is found, an enzyme is activated and releases a detectable signal.

Dhanda said the kit can test samples from 100 patients at once and requires smaller amounts of chemical reagents, which have sometimes been in short supply.

The biotech collaborated on the test’s development with Feng Zhang, one of the inventors of CRISPR. Zhang teaches at the Massachusetts Institute of Technology and is a core member of the Broad Institute of MIT and Harvard. The test is called SHERLOCK, which stands for Specific High-sensitivity Enzymatic Reporter unLOCKing.

“When our lab collaborated with Dr. Feng Zhang’s team to develop SHERLOCK, we believed that this CRISPR-based diagnostic method would have a significant impact on global health,” said James Collins, cofounder of the firm and a professor of medical engineering and science at MIT.

He said the test is “not only faster than what we’re seeing with real-time PCR test kits, it is more precise, providing true positive and true negatives with 100 percent accuracy in patient samples.”

Dhanda said other companies are selling tests for as much as $50 but he expected his firm’s test to cost about half that.

Sherlock is also working on a CRISPR-based test that primary care physicians could use to check patients at their offices, Dhanda said. And the firm wants to create another test that patients could use at home, like an over-the-counter pregnancy test.


Dr. Barry Bloom, a professor at the Harvard T.H. Chan School of Public Health, said in an online forum on COVID-19 Thursday that “there is a desperate need for a test like a pregnancy test where the results can be obtained in a matter of minutes.”

The FDA has provided more than two dozen emergency use authorizations for diagnostic tests developed by hospitals and private companies since late March. They are intended to make tests, medical devices, and medicines available faster than with ordinary FDA approvals but are for use only during the emergency.

Jonathan Saltzman can be reached at