Personalis, Inc. (Nasdaq: PSNL), a leader in advanced genomics for precision oncology, today announced the publication of one of the largest and most comprehensive patient cohorts to date from the landmark TRACERx study, in the journal Cell. The study, titled "Longitudinal ultrasensitive ctDNA monitoring for high-resolution lung cancer risk prediction," demonstrates the clinical importance of ultrasensitive, tumor-informed molecular residual disease (MRD) testing in stage I to III non-small cell lung cancer (NSCLC).

The study, led by Professor Charles Swanton at the Francis Crick Institute and University College London (UCL) in collaboration with Personalis, analyzed 431 NSCLC patients tracked for a median of > 5 years using the NeXT Personal® test. It demonstrated that the NeXT Personal test allows for highly sensitive detection of small traces of circulating tumor DNA (ctDNA) in blood samples from lung cancer diagnosis through to surveillance, even in hard-to-detect subtypes.

Key Findings:

• Comprehensive Cancer Detection From Diagnosis Through Surveillance: NeXT Personal demonstrated exceptional sensitivity and specificity for detecting residual and recurrent cancer throughout the patient course at diagnosis (pre-surgery), post-surgical (landmark), during adjuvant, and during long-term surveillance monitoring, with many of the detections (~36-43%) in the ultrasensitive range.
• Cancer Detection Ahead of Imaging: Cancer was detected a median of ~5 to ~9 months and up to ~57 months ahead of standard of care imaging post-surgery and during surveillance.
• Ultrasensitive Detection and Risk Stratification: The study demonstrated NeXT Personal detection of ctDNA pre-treatment, post-surgery, and during surveillance was associated with higher risk of relapse and worse overall survival. The study also identified an intermediate risk patient subgroup with ultrasensitive ctDNA detections that can benefit from close clinical follow-up.
• Therapy Monitoring: Patients who did not clear their ctDNA during adjuvant chemotherapy were > 5 times more likely to relapse than those who cleared their ctDNA.

The study utilized Personalis’ NeXT Personal technology, which leverages whole-genome sequencing and proprietary noise suppression to detect ctDNA at levels down to ~1 PPM. The Cell publication highlights that a significant portion of relapsing patients presented with ctDNA levels in the ultrasensitive range, detections which can be missed with less sensitive tests.

“This latest TRACERx study underscores the critical role of ultrasensitive ctDNA monitoring in early-stage lung cancer,” said Professor Charles Swanton, Director of the Cancer Research UK Lung Cancer Centre of Excellence and Chief Clinician at Cancer Research UK. “The ability to detect residual disease at extremely low levels allows us to detect traces of cancer earlier after surgical resection in the adjuvant setting and more effectively identify patients at risk for relapse. It also allows us to see how patients are responding to adjuvant therapy with more accuracy, paving the way for more personalized, data-driven treatment strategies.”

Richard Chen, M.D., Chief Medical Officer and Executive VP of R&D at Personalis, added: "This publication in Cell confirms that NeXT Personal’s high test-sensitivity and specificity are not just technical specifications, they are key to unlocking clinical utility. By pioneering ultrasensitive MRD testing, we are leading the way in enabling the next generation of cancer care and giving physicians the tools they need to better guide treatment decisions throughout the patient journey."

This publication joins a list of other leading publications this year in Nature Medicine and Annals of Oncology for NeXT Personal, showing the importance of ultrasensitive MRD testing in lung cancer and other cancer types.

About Personalis, Inc.

At Personalis, we are transforming the active management of cancer through breakthrough personalized testing. We aim to drive a new paradigm for cancer management, guiding care throughout the patient journey. Our highly sensitive assays combine tumor-and-normal profiling with proprietary algorithms to deliver advanced insights even as cancer evolves over time. Our products are designed to detect minimal residual disease (MRD) and recurrence at the earliest timepoints, enable selection of targeted therapies based on ultra-comprehensive genomic profiling, and enhance biomarker strategy for drug development. Personalis is based in Fremont, California. To learn more, visit www.personalis.com and connect with us on LinkedIn and X (Twitter).

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include all statements that are not historical facts, including statements relating to: the attributes, advantages, sensitivity, and clinical relevance of the NeXT Personal test and the potential impact or expected benefits of the TRACERx study. Such forward-looking statements involve known and unknown risks and uncertainties and other factors that may cause actual results to differ materially from any anticipated results or expectations expressed or implied by such statements, including the risks, uncertainties and other factors that relate to Personalis’ ability to demonstrate attributes, advantages or clinical validity of the NeXT Personal test, including the NeXT Personal MRD assay remaining unique in its ability to detect traces of cancer in the ultra-sensitive range; future clinical data differing from the clinical data previously presented or expected results; the rate of adoption and use of the NeXT Personal test; changes in health care policy could increase Personalis’ costs, decrease Personalis’ revenue, and impact sales of and reimbursement for Personalis’ tests; the impact of competition and macroeconomic factors on Personalis’ business; having a limited number of suppliers; and customer concentration. These and other potential risks and uncertainties that could cause actual results to differ materially from the results predicted in these forward-looking statements are described under the captions “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in Personalis’ Annual Report on Form 10-K for the year ended December 31, 2024, filed with the Securities and Exchange Commission (SEC) on February 27, 2025 and subsequent Quarterly Reports on Form 10-Q, including the Quarterly Report on Form 10-Q for the quarter ended September 30, 2025, filed with the SEC on November 4, 2025. All information provided in this release is as of the date of this press release, and any forward-looking statements contained herein are based on assumptions that we believe to be reasonable as of this date. Undue reliance should not be placed on the forward-looking statements in this press release, which are based on information available to us on the date hereof. Personalis undertakes no duty to update this information unless required by law.

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