Grail shares had their best day in 1.5 years. The regulator may approve its cancer test

Shares of the mid-cap company Grail soared by a third on September 21, marking their best performance since February 2025. This came after the U.S. Food and Drug Administration (FDA) released documents indicating that it is open to approving the company’s test for detecting multiple types of cancer at once. This conclusion was more favorable than investors had expected, according to The Wall Street Journal.

Grail shares surged nearly 34% to $108 during trading on September 21. This is their best performance since February 2025, according to Stocktwits.

The FDA's conclusion, prepared for the advisory committee meeting on September 23 and concerning Grail's test for screening multiple types of cancer at once, turned out to be better than investors had expected, according to The Wall Street Journal.

All FDA-approved screening methods detect a single specific type of cancer, whereas Grail’s test, called Galleri, claims to be able to detect more than 50 types of cancer in the blood of people over the age of 50.

However, clinical trial data published in February 2026 showed that the test was not as effective as planned for screening for late-stage cancer. This news caused Grail’s stock price to plummet by half in just one day.

The test also performs poorly at detecting cancer in its early stages, identifying it in only 20–30% of cases, Scott Ramsey, director of the Fred Hutchinson Cancer Research Institute’s Institute for Outcomes Research, told the WSJ. “With such low sensitivity, the test misses more cases of cancer than it detects, especially in the early stages,” he said.

According to the FDA’s conclusion published on September 21, the agency’s staff had no remaining questions regarding how the test was developed, how the studies were designed, or the key safety data. The main questions the regulator posed to the committee concern the risk-benefit ratio of the test for patients, as well as whether Galleri can be classified as a test for the “early detection” of cancer or merely as a cancer screening test.

Following the meeting, the committee will vote for or against approving the test. Its recommendations are not binding on the FDA, but a positive review would increase Galleri's chances of approval, according to Stocktwits.

Grail has been selling Galleri since 2021. U.S. law allows this to be done without FDA approval—but only in medical laboratories and only with a doctor’s prescription, at the patient’s own expense. A positive decision by the regulator would allow the test to be included in the Medicare program, which will cover such tests starting in 2028.

Since the beginning of the year, Grail's stock price has jumped 26%—taking into account the rally on September 21.

However, Wall Street remains cautious in its assessment of the company's prospects: six analysts recommend holding its stock, and five recommend buying it. The average price target is $82.4, which is nearly 24% below the latest closing price.