FDA Staff Find No Major Concerns With Galleri Multicancer Early Detection Test

FDA staff members had no major concerns or questions about the safety, accuracy, risks, or benefits of the Galleri multicancer early detection (MCED) blood test ahead of an advisors’ meeting that will be held Wednesday.

The prescription, qualitative in vitro diagnostic test from Grail is intended to screen for early detection of multiple types of cancer in adults ages 50 and older.

In a briefing document released ahead of the meeting, FDA staff pointed out that most cancer deaths expected to occur in the U.S. result from cancer types for which there are no guideline-recommended screening programs.

“Blood-based multicancer detection tests offer the potential to detect multiple types of cancer through a single blood draw,” agency staff members wrote. “Screening tests, such as Galleri, that detect cancers for which there are no guideline-recommended screening options may provide detection of cancers that would otherwise go undetected, thereby helping to address an unmet medical need.”

Risks associated with false positive and false negative results of a blood-based screening test should be carefully considered, they stated.

While FDA staff often will weigh in on positive or negative aspects of a device or test before an advisory committee meeting, they appeared this time to take a neutral stance on the data shown in the PATHFINDER 2 study and the randomized NHS-Galleri trial.

PATHFINDER 2 was designed to evaluate the safety of Galleri in terms of diagnostic testing triggered by the MCED test result, and to assess the performance of the test in individuals eligible for cancer screening.

The NHS-Galleri study was a prospective, randomized controlled trial in which participants ages 50-77 with no clinical suspicion of cancer were enrolled to assess the performance of the Galleri MCED test for population screening in the U.K. when added to standard of care.

Data from NHS-Galleri presented at the American Society of Clinical Oncology annual meeting in May showed the study failed to meet its primary outcome of reducing the number of cancers detected at stage III or IV across a dozen tumor types for which no screening tests are currently available, although it detected more stage I and II cancers.

The FDA briefing document did not review that endpoint. Instead, it focused on test performance and safety results from participants with 1 year of follow-up in PATHFINDER 2, as well as data from participants in the intervention arm of the prevalent screening round (first year) of the NHS-Galleri trial.

Results from PATHFINDER 2 showed Galleri had a 12-month episode sensitivity of 35.0%, specificity of 99.85%, positive predictive value (PPV) of 77.0%, negative predictive value (NPV) of 99.07%, and cancer signal origin (CSO) prediction accuracy of 94.3%.

In NHS-Galleri, the test demonstrated a 12-month episode sensitivity of 31.6%, specificity of 99.74%, PPV of 66.2%, NPV of 98.89%, and CSO predictive accuracy 0f 91.9%.

On Wednesday, members of the molecular and clinical genetics panel of the FDA’s Medical Devices Advisory Committee will vote on whether:

• There is reasonable assurance that Galleri is safe for use in patients who meet criteria specified in the proposed indication.
• There is reasonable assurance that Galleri is effective for patients who meet that criteria.
• The benefits of Galleri outweigh the risks in these patients.

The FDA also will ask the panel for advice on appropriate labeling for Galleri, including warnings and other risk mitigation strategies, as well as how performance and limitations of the test should be communicated to healthcare providers and patients.

While not bound by its advisors’ recommendations, the FDA usually follows their advice.