GRAIL Galleri Multi-Cancer Early Blood Test: A Historic FDA Advisory Committee Review
Milestone Event
The U.S. Food and Drug Administration (FDA) announced it will convene a Medical Devices Advisory Committee (Molecular and Clinical Genetics Panel) meeting on September 23, 2026, to review GRAIL's Premarket Approval (PMA) application for the Galleri multi-cancer early detection (MCED) blood test.
This marks the first time ever that a multi-cancer early detection test has undergone formal FDA advisory committee review, representing a critical step forward in the regulatory pathway for AI-driven liquid biopsy technology.
Galleri Technology Principles
Galleri is a liquid biopsy test whose core technology uses artificial intelligence to analyze DNA methylation patterns circulating in the blood.
How It Works
When cancer cells die, they release DNA fragments with specific methylation markers into the bloodstream. Different types of cancer have characteristic DNA methylation patterns. Galleri's AI system analyzes these patterns to:
- Detect cancer signals: Identify whether cancer-associated DNA methylation patterns are present in the blood
- Predict tissue of origin: If a cancer signal is detected, further predict the tissue type where the cancer likely originated, helping clinicians guide subsequent diagnostic evaluations
Galleri is designed to simultaneously detect over 50 cancer types, including many cancers that currently lack standard screening methods (such as pancreatic cancer, ovarian cancer, etc.).
Positioning
Importantly, Galleri is designed to supplement rather than replace existing guideline-recommended cancer screenings (such as mammography for breast cancer, colonoscopy for colorectal cancer), not to substitute these established screening methods.
Clinical Data Support
GRAIL's PMA application is supported by extensive clinical evidence:
PATHFINDER 2 Study
| Item | Data |
|---|---|
| Participants | 25,490 people |
| Study location | United States |
| Follow-up period | 1 year |
| Study purpose | Evaluate test performance and safety profile |
NHS-Galleri Trial
| Item | Data |
|---|---|
| Intervention arm participants | Over 70,000 people |
| Trial type | Randomized Controlled Trial (RCT) |
| Trial scale | Largest MCED test RCT to date |
| Trial location | UK National Health Service (NHS) |
The NHS-Galleri trial is the largest randomized controlled trial of a multi-cancer early detection test in an intended-use population to date, and its data carries significant weight in the FDA review.
Bridging Analysis
The submission also includes a bridging analysis comparing the performance of the test version used in clinical trials with the updated version currently proposed for FDA approval, ensuring the regulatory review is based on the latest version of the technology.
Regulatory Background
Galleri received FDA "Breakthrough Device" designation in 2018, which accelerated its regulatory review process. GRAIL formally submitted its PMA application on January 29, 2026.
The September 23 advisory committee meeting will be a critical node in the FDA review process. The committee will provide recommendations to the FDA, which will then make a final determination on the PMA application following the meeting.
Industry Impact
As the first MCED test to undergo FDA advisory committee review, Galleri's review outcome is expected to have far-reaching implications for regulatory expectations across the entire multi-cancer blood screening field.
If the FDA ultimately approves Galleri, this would:
- Provide important reference for the regulatory pathway of other MCED tests
- Potentially prompt health insurance providers to reassess coverage policies for MCED tests
- Accelerate the commercialization of AI-driven liquid biopsy technology
AI's Role in Galleri
Galleri's AI system must handle extremely complex biological signal analysis tasks:
Data Complexity: cfDNA (cell-free DNA) in blood comes from various cells throughout the body, with cancer-related signals representing an extremely small fraction of the large volume of normal cell signals. Highly sensitive AI algorithms are required for reliable identification.
Multi-Cancer Classification: Simultaneously distinguishing methylation patterns across over 50 cancer types and accurately predicting tissue of origin is a high-dimensional classification problem.
False Positive Control: In screening scenarios, false positives (incorrectly reporting cancer) lead to unnecessary follow-up tests and patient anxiety. The AI system must achieve a delicate balance between sensitivity and specificity.
Asia-Pacific Perspective
For the Asia-Pacific region, Galleri's FDA review carries important reference significance:
Cancer Burden: The Asia-Pacific region bears approximately 50% of global new cancer cases. Breakthroughs in multi-cancer early detection technology have particularly important public health significance for this region.
Regulatory Influence: The FDA review outcome will provide important reference for Asia-Pacific regulatory authorities (such as China's NMPA, Japan's PMDA, Singapore's HSA) evaluating similar technologies.
Local Research: Japan, South Korea, and China all have domestic institutions conducting similar multi-cancer liquid biopsy research. The FDA's review standards for Galleri will provide guidance for the regulatory pathways of these domestic technologies.
Challenges and Controversies
Despite Galleri's impressive clinical data, it also faces some challenges:
Complexity of UK Trial Results: Early reports indicated that some results from the NHS-Galleri trial were controversial, which is one reason the FDA decided to convene an advisory committee.
Cost Accessibility: The current cost of the Galleri test is approximately $949, and most insurance plans have not yet covered it, limiting widespread adoption.
Clinical Significance of Early Detection: Whether early detection of cancer signals necessarily improves patient outcomes still requires longer-term follow-up data to verify.
Conclusion
The FDA advisory committee review of GRAIL Galleri is an important milestone in AI-driven medical diagnostic technology moving toward mainstream clinical application. Regardless of the final review outcome, this process will lay the foundation for the regulatory framework of the entire multi-cancer early detection field.
For healthcare institutions, regulatory authorities, and patients in the Asia-Pacific region, closely following this review process will help prepare for the introduction and regulation of similar technologies in the region.
