Personalis Highlights Early Colorectal Cancer Recurrence Detection and Ultrasensitive MRD Performance Across a Broad Set of Tumor Types at ASCO 2026

• NeXT Personal® MRD test showed 100% sensitivity for CRC recurrence during surveillance and 82% landmark sensitivity 4 weeks post-surgery
• Ultrasensitive NeXT Personal performance was demonstrated across 6 different solid tumor types

FREMONT, Calif.--(BUSINESS WIRE)--Personalis, Inc. (Nasdaq: PSNL) today announced clinical data from the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting establishing the clinical importance of ultrasensitive MRD detection across six solid tumor types, led by the VICTORI colorectal cancer and TRACERx lung cancer studies.

“Our ASCO data continues to build on a compelling body of evidence, including recent landmark publications, that show ultrasensitive MRD detection with NeXT Personal enables early detection of patients at risk for relapse, across a broad set of solid tumor types,” said Richard Chen, MD, MS, President and Chief Medical Officer of Personalis. “These data, along with our recent Medicare approvals, further our mission to provide cancer patients with the precision MRD testing they need to help guide clinical management.”

Key clinical themes and data presented at the meeting included:

Exceptional Performance in Colorectal Cancer

The prospective VICTORI study (Abstract #396), led by the University of British Columbia, monitored over 100 Stage I-IV resectable CRC patients with NeXT Personal. Highlights from the interim analysis include:

• 100% sensitivity for cancer relapse during surveillance, ahead of imaging: NeXT Personal successfully detected 100% of all patient relapses in the cohort ahead of clinical imaging, including all distant metastases in historically difficult-to-detect regions like the lung.
• 82% landmark sensitivity at 4 weeks after surgery: Just four weeks after surgery, the test detected 82% of patients who later relapsed, providing clinicians with a highly reliable early signal of cancer to inform treatment pathways.

Importance of Sub-10 ppm Sensitivity in Lung Cancer

In an oral podium presentation (Abstract #8017), investigators from University College London utilized the landmark TRACERx cohort to analyze 431 Stage IA-IIIB non-small cell lung cancer (NSCLC) patients using NeXT Personal. The study demonstrated the clinical utility of detecting ctDNA at ultra-low thresholds:

• Consistent Ultra-Low Limits of Detection: NeXT Personal demonstrated consistent detection of ctDNA at ultra-low levels in this study, achieving a median limit of detection (LOD) of 1.66 ppm.
• Prevalence of Sub-10 ppm Detections: Building on prior NeXT Personal publications showing approximately 40% of TRACERx detections were in the ultrasensitive range (<100 ppm), this additional analysis showed that a significant portion of detections are found at the lowest limits of detection less than 10ppm. Approximately 21% of pre-operative adenocarcinoma and 18% of post-operative landmark detections were below 10 ppm—thresholds frequently missed by less sensitive assays.
• Clinical importance: The clinical importance of detecting these ultra-low levels was established. Patients with post-operative landmark detections below 10 ppm (within 10–120 days post-surgery) experienced a 3-fold increased risk of recurrence compared to patients with undetectable ctDNA, potentially enabling much earlier clinical intervention.

Growing Breadth of Evidence Across Diverse Solid Tumors

Beyond colorectal and lung cancers, ASCO presentations highlighted the ultrasensitive performance of NeXT Personal in a broad array of additional tumor types:

• Ovarian Cancer (Abstract #233): In collaboration with MD Anderson Cancer Center, 72 patients with high-grade epithelial ovarian cancer were evaluated following frontline chemotherapy and surgery. ctDNA detection correlated with a 3.5-fold risk increase for progression. Overall, NeXT Personal showed comparable sensitivity and specificity to second-look laparoscopy (SLL), suggesting its potential as a non-invasive SLL alternative.
• Endometrial Cancer (Abstract #277): MD Anderson investigators found that ctDNA clearance post-treatment in 99 Stage I-IV patients reduced recurrence risk 29-fold. Notably, 46% of detections were in the ultrasensitive range, reinforcing the need for high-sensitivity testing.
• Melanoma (Abstract #288): A NeXT Personal study from the University Medical Center Hamburg-Eppendorf (UKE) on 98 unresectable and resected melanoma patients demonstrated that ctDNA clearance and on-treatment dynamics predicted response. The unresectable melanoma cohort demonstrated 100% pre-treatment baseline ctDNA detection in first-line patients, with early on-therapy ctDNA decreases associated with a reduced risk of progression. The resected melanoma cohort demonstrated that increasing ctDNA during adjuvant therapy was associated with an approximately 5-fold higher risk of distant metastasis, and ultrasensitive monitoring identified recurrences a median of 212 days prior to imaging.
• Renal Cell Carcinoma (Abstract #30): Investigators from the Instituto de Investigación Sanitaria (IDIS) demonstrated that ultrasensitive ctDNA detection and molecular clearance serve as robust prognostic markers in advanced renal cell carcinoma. NeXT Personal demonstrated a high pre-treatment baseline ctDNA detection rate of 84%. Patients who failed to achieve molecular ctDNA clearance (mCR) during first-line therapy experienced significantly worse outcomes, including a more than 7-fold increase in the risk of progression and a nearly 4-fold increase in the risk of death.

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: breadth of tumor types, the clinical utility, performance characteristics and specific applications of the NeXT Personal test, including its potential to inform clinical management and intervention, our ability to drive a new paradigm for cancer management, and the design of Personalis’ products. 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 or utility of the NeXT Personal test, including the NeXT Personal MRD assay remaining unique in its ability to detect traces of cancer in the ultrasensitive range, the ability of the NeXT Personal test to consistently detect circulating tumor DNA at ultra-low thresholds such as single-digit parts-per-million (ppm), identify recurrence early, achieve 100% longitudinal sensitivity for recurrence—including difficult-to-detect metastatic sites—or >80% landmark sensitivity as early as four weeks post-surgery, serve as a non-invasive alternative to other diagnostic procedures (such as SLL), inform treatment pathways, evaluate treatment response, or predict patient outcomes; 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, which could increase Personalis’ costs, decrease Personalis’ revenue, and impact sales of and reimbursement for Personalis’ tests; Personalis’ ability to obtain Medicare coverage and reimbursement and the timing thereof; the impact of competition and macroeconomic factors on Personalis’ business; the partnering and/or collaboration arrangements that Personalis has entered into or may enter into in the future may not be successful, or may terminate, which could adversely impact Personalis’ business or affect its ability to develop and commercialize its services and products; 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, 2025, filed with the Securities and Exchange Commission (SEC) on February 26, 2026, and Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, filed with the SEC on May 7, 2026. 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.