(Bloomberg) — Guardant Health Inc. fell the most in its history from Thursday’s close after results of a study of its blood test for colorectal cancer disappointed investors.
The test accurately identified the presence of cancer or precancer 83% of the time, with a false positivity rate of 10%, according to a Guardant statement late Thursday. The shares sank 31% at 10:16 am Friday in New York. Shares of rival Exact Sciences Corp., which makes a test called Cologuard that looks for signs of colorectal cancer in stool samples and is more accurate, rose more than 26% from Thursday’s closing price.
Investors had expected the test would be 85% accurate when cancer was present, according to Patrick Donnelly, an analyst from Citigroup Inc. Shareholders were also looking for a higher rate of accuracy in detecting benign tumors that can turn cancerous, he said in a note to clients. He dropped his price target to $60 from $80.
The data aren’t strong enough to make Guardant’s test a first line option ahead of Cologuard in patients who don’t want to undergo colonoscopies, another standard screening procedure, according to a research note from Brandon Couillard, an analyst at Jefferies.
Guardant is one of the companies working to develop blood tests for cancer, sometimes called liquid biopsies. The assays might find cancer with minimal invasiveness and in its earliest, most treatable stages.
The company study began in October 2019, registering 20,000 adults with no known high-risk factors, according to a government trial tracker. Guardant said it plans to finish its US regulatory application in the first quarter of 2023.
Guardant’s co-Chief Executive Officer AmirAli Talasaz said in an interview he remains confident in the product.
“There’s some lack of understanding of the fact that this is strong data,” Talasaz said. “It’s the data that’s going to pave the path for a FDA approval.”
–With assistance from Alexandra Muller.
(Updates with new details, comment from executive starting in second paragraph, analyst notes)
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