Study results
published in The Lancet

PATHFINDER supports using Galleri® for cancer screening
Key Results from the PATHFINDER Study

6,621

participants ≥50 yearsof age screened using
the MCED blood test

The PATHFINDER Study is an interventional, prospective, multi-center study that
evaluated an early version of Galleri, GRAIL’s multi-cancer early detection (MCED)
blood test.1 The study marks the first time the MCED test was used to return results tohealthcare providers and participants to help guide appropriate diagnostic workup.

Adding MCED to standard-of-care screening approximately doubled the number of cancers detected.*
These include early-stage cancers and those without existing guideline recommended screening.1

35Additional participants
with cancer*
detected by the early version
of Galleri vs. 38 cancers detectedby standard-of-care andnonstandard screening*

74%

48%

of cancers* detected by theearly version of Galleri are notroutinely screened forof cancers* detected by the earlyversion of Galleri were stage I-II

*Cancers detected refer to cancers that were confirmed by diagnostic workup after screening with the early version of Galleri, or standard and non-standard screening. Standard-of-care or standard
screening refers to USPSTF (United States Preventive Services Task Force) recommended screening for breast, cervical, colorectal, lung, and prostate cancer. Cancers detected by nonstandard screeningrefers to those that lack USPSTF screening recommendations such as thyroid and melanoma.

Galleri performance in the PATHFINDER Study supports feasibility of broad screening use1

99.5% Specificity

43.1% PPV

88% Accuracy

indicating low false positiverate (0.5%)

consistent with previously
reported results3

in predicting the top two Cancer
Signal Origins among true positive
participants, helping guidediagnostic workup

PPV = The proportion of people with “Cancer Signal Detected” results diagnosed with cancer.

The Galleri® test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older. The Galleri test should be used in addition to guideline recommended cancer screenings
such as mammography, colonoscopy, PSA, or cervical cancer screening. The Galleri test does not detect all cancers and all cancers cannot be detected in the blood. False positive results and false negative
results do occur.

Screening with the early version of Galleri was safely implemented,
with high participant satisfaction2‡
There were no adverse events
due to diagnostic workup
prompted by receipt of a“signal detected” test result.
There were four studyrelated adverse events (tworelated to mild anxiety
before the test, one related
to mild anxiety about theblood draw, and one related
to mild bruising).

High satisfaction rates among PATHFINDER participantsII
irrespective of test results‡% OF PARTICIPANTS SATISFIED ¶ WITH THE MCED TESTNo Cancer
Signal Detected

Signal Detected WithoutCancer Diagnosis

Signal Detected WithCancer Diagnosis

97.2%

82.3%

92.0%

n=5,861

n=34

n=25

Study Design

6,621 adults ≥50 years enrolledfrom 7 US sites into 2 cohorts:
witha and without additional risk

MCED testorderedPrespecified reanalysisof blood samples withcurrent version of Galleri

Questionnaire forParticipantsb

Blood drawn
and shipped

Test report
generated

Signal Detected

No Signal Detected

Test resultcommunicatedProvider determines
follow-up

Test result reported
Participant counseled tocontinue recommended
screening

Diagnostic Resolutionc
Cancer or no cancer
a. About half of participants had additional cancer
risk (previous history of cancer, smoking, andgenetic risk); b. Also collected at other time points
during the study; c. Defined as date when study
team determines to end diagnostic evaluation
triggered by a “signal detected” test result.

Cancer Status
Assessed at 12 months

Cancer Status
Assessed at 12 months

Clinical Study Site Institutions

Important Safety Information: The Galleri® test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 orolder. The Galleri test does not detect all cancers and should be used in addition to routine cancer screening tests recommended by a healthcare
provider. Galleri is intended to detect cancer signals and predict where in the body the cancer signal is located. Use of Galleri is not recommended
in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment. Results should be interpreted by a healthcare
provider in the context of medical history, clinical signs and symptoms. A test result of “Cancer Signal Not Detected“ does not rule out cancer. A
test result of “Cancer Signal Detected” requires confirmatory diagnostic evaluation by medically established procedures (e.g. imaging) to confirm
cancer. If cancer is not confirmed with further testing, it could mean that cancer is not present or testing was insufficient to detect cancer, including
due to the cancer being located in a different part of the body. False-positive (a cancer signal detected when cancer is not present) and falsenegative (a cancer signal not detected when cancer is present) test results do occur. Rx only.
Laboratory / Test Information: GRAIL’s clinical laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA)
and accredited by theCollege of American Pathologists (CAP). The Galleri test was developed, and its performance characteristics were determined
by GRAIL. The Galleri test has not been cleared or approved by the Food and Drug Administration. GRAIL’s clinical laboratory is regulated under
CLIA to perform high-complexity testing. The Galleri test is intended for clinical purposes.
References:
1. Schrag D, Beer TM, McDonnell III CH, et al. Blood-based tests for multicancer early detection (PATHFINDER): a prospective cohort study. Lancet 2023;402:1251–60.
2. Schrag D, et al. Evaluation of Anxiety, Distress and Satisfaction Using a Multi-Cancer Early Detection (MCED) Test. Presentation at European Society for Medical Oncology (ESMO) Congress;
September 9-13, 2022.
3. Klein EA, Richards D, Cohn A, et al. Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set. Ann Oncol. 2021;32(9):1167-1177.
doi: 10.1016/j.annonc.2021.05.806.

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