— Proprietary Methylation Technology Selected for Continued Development of Multi-Cancer Test —

— CCGA and STRIVE Studies Fully Enrolled with Approximately 115,000 Participants; Enrollment Initiated in 50,000-Participant SUMMIT Study —

— New Data from CCGA to be Presented at 2019 American Society of Clinical Oncology Annual Meeting —

MENLO PARK, Calif., May 13, 2019 – GRAIL, Inc., a healthcare company whose mission is to detect cancer early, when it can be cured, today announced that its multi-cancer test has been granted Breakthrough Device designation from the U.S. Food and Drug Administration (FDA). The investigational blood test is in development for the early detection of multiple cancer types in individuals aged 50 or older. The FDA grants Breakthrough designation to devices that have the potential to provide for more effective diagnosis of life-threatening diseases such as cancer. The goal of the FDA’s Breakthrough Devices Program is to provide patients and healthcare providers with timely access to medical devices granted the designation by speeding up their development, assessment, and review.

“We’re excited the FDA recognizes the potential of our multi-cancer early detection blood test. There are no effective early detection tests for the majority of cancer types, and many deadly cancers are often detected too late. We hope our test may offer a chance to address these challenges,” said Jennifer Cook, Chief Executive Officer. “We have made significant progress developing our multi-cancer test and look forward to sharing new data at ASCO and other medical conferences this year.”

GRAIL previously reported data from the first pre-planned sub-study of its Circulating Cell-free Genome Atlas (CCGA) study, which showed that its three prototype next-generation sequencing (NGS) blood tests were able to detect multiple deadly cancer types from a single blood draw, with a low rate of false positive results (high specificity).¹ The company has since selected methylation as its preferred approach and has developed a methylation sequencing blood test that preferentially targets the most informative regions of the genome to both detect the presence of multiple types of cancer and identify the tissue of origin (the part of the body where the cancer originated). The blood test is currently being evaluated in the second pre-planned sub-study of CCGA.

New results from CCGA will be presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting, including data on the ability of the company’s methylation technology to identify the tissue of origin when cancer is present. An analysis of survival of participants whose cancer was detected by the methylation technology, compared with those whose cancer was not detected by the technology, will also be presented.

About GRAIL’s Clinical Program

GRAIL is conducting what the company believes to be one of the largest clinical research programs ever pursued in genomic medicine. The program consists of three large-scale studies designed to enroll approximately 165,000 participants to create an atlas of genomic cancer signals in the blood, and to develop and evaluate GRAIL’s blood test for the early detection of multiple cancer types. Approximately 115,000 participants have been enrolled to date.

The CCGA study is a prospective, observational, longitudinal study that has completed enrollment of approximately 15,000 people with and without cancer across 142 sites in the United States and Canada. GRAIL is conducting three pre-planned sub-studies within CCGA to discover, train, and validate its multi-cancer early detection test.

The STRIVE study is a prospective, observational, longitudinal cohort study that has completed enrollment of approximately 100,000 women at the time of their screening mammogram across 37 sites in the United States. STRIVE is designed for clinical validation of GRAIL’s multi-cancer test in an intended use population. GRAIL anticipates reporting data from STRIVE in 2020.

The SUMMIT study is a prospective, observational, longitudinal cohort study that is enrolling participants in London in the United Kingdom. The study is designed to enroll approximately 50,000 men and women who do not have a cancer diagnosis at the time of enrollment. Approximately half of the participants will be people at high risk of lung and other cancers due to a significant smoking history, and the other half will be people who are not at high risk for cancer based on smoking history. SUMMIT is designed for clinical validation of GRAIL’s multi-cancer test in a second intended use population and to evaluate clinical utility of the test in a high-risk population.

About GRAIL’s Methylation Technology

GRAIL is developing an NGS blood test for the early detection of multiple deadly cancer types. GRAIL’s methylation technology preferentially targets the most informative regions of the genome and uses machine-learning algorithms to both detect the presence of cancer and identify the tumor’s tissue of origin when cancer is present.

DNA methylation is a natural process used by cells to regulate gene expression. It is a chemical modification to DNA and a well-studied epigenomic feature of the genome. In cancer, abnormal methylation patterns and the resulting changes in gene expression can contribute to tumor growth. For example, hypermethylation can cause tumor-suppressor genes to be inactivated.

About GRAIL

GRAIL is a healthcare company whose mission is to detect cancer early, when it can be cured. GRAIL is focused on alleviating the global burden of cancer by developing pioneering technology to detect and identify multiple deadly cancer types early. The company is using the power of next-generation sequencing, population-scale clinical studies, and state-of-the-art computer science and data science to enhance the scientific understanding of cancer biology, and to develop its multi-cancer early detection blood test. GRAIL is located in Menlo Park, California. It is supported by leading global investors and pharmaceutical, technology, and healthcare companies. For more information, please visit www.grail.com.

^[1] Klein EA et al., J Clin Oncol. 2018;36 (suppl; abstr 12021); https://grail.com/wp-content/uploads/2018/09/ASCO_2018_CCGA-Multi-Cancer_Klein_POS_Final.pdf