Personalis and Collaborators to Highlight Ultrasensitive ctDNA Data and New Therapy Resistance Tracking Capabilities at AACR 2026

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Key Terms

ctdna medical

Circulating tumor DNA (ctDNA) is tiny fragments of genetic material shed by cancer cells into the bloodstream, like breadcrumbs that can reveal a tumor’s presence and genetic makeup without needing a biopsy. For investors, ctDNA matters because tests and technologies that detect and analyze these fragments can speed diagnosis, track treatment response, and signal relapse, creating commercial opportunities in diagnostics, personalized therapies, and monitoring services.

mrd medical

MRD stands for minimal residual disease, the tiny number of cancer cells that can remain in the body after treatment and that may not show up on routine scans. Detecting MRD is like finding a few seeds left in a garden after clearing: it helps doctors predict the chance of relapse and measure how effective a therapy is, which investors watch because MRD results can influence clinical trial success, regulatory decisions, and a drug’s market potential.

tumor-infiltrating tcr repertoire medical

The tumor-infiltrating TCR repertoire is the mix and variety of T‑cell receptors carried by immune cells that have entered a tumor; T‑cell receptors are the molecular “IDs” immune cells use to recognize specific threats. For investors, this repertoire acts like a snapshot of the tumor’s immune activity—its diversity and dominance patterns can signal how well immunotherapies may work or whether a cancer is likely to resist treatment, making it a key indicator for drug development and clinical prospects.

esr1 medical

ESR1 is a gene that makes the estrogen receptor alpha protein, a cellular “lock” that the hormone estrogen (the “key”) fits into to tell cells how to grow, divide and behave. Mutations or changes in ESR1 can change how cancers—especially breast and other hormone-driven tumors—respond to hormone-blocking drugs, so investors track ESR1-linked tests, drugs and trial results because they directly affect treatment choices, market size and regulatory chances in oncology and women’s health.

tumor mutation burden medical

Tumor mutation burden (TMB) measures how many genetic changes a tumor has by counting mutations in a set amount of its DNA; think of it as the number of spelling errors in a book page. Investors care because tumors with more mutations are often more likely to trigger a patient’s immune system and respond to certain immunotherapy drugs, affecting drug development prospects, trial outcomes, and the commercial value of treatments.

non-small cell lung cancer medical

A broad category of lung tumors that grow from the cells lining the airways and make up the majority of lung cancer cases; it includes several subtypes that behave and respond to treatment differently, like different models of the same car family. It matters to investors because its large patient population and variety of treatment options — surgery, traditional chemo, targeted drugs and immunotherapies — create major markets where clinical trial results, drug approvals or changing treatment guidelines can quickly affect a company’s revenue and stock value.

immunotherapy medical

Treatment that uses or enhances the body’s immune system to detect and fight disease, most often cancers or chronic infections; think of it as training or arming the body’s own soldiers to find and destroy targets. It matters to investors because successful immunotherapies can lead to high-value drug approvals, recurring revenue from long-term treatments, and changes in competitive dynamics, while failures or safety issues in clinical trials can materially affect company valuations.

minimal residual disease medical

Minimal residual disease (MRD) is the tiny number of cancer cells that remain in the body after treatment, often too few to show up on standard scans but detectable with very sensitive tests. For investors, MRD is important because it predicts the risk of relapse and can determine whether a therapy is seen as effective, influences regulatory and reimbursement decisions, and affects the size and timing of a drug’s market opportunity—like spotting the last weeds that can make a garden regrow if not removed.

04/13/2026 - 06:00 AM

Oral podium presentation to highlight NeXT Personal^® in colorectal cancer; Personalis to debut first data for Real-Time Variant Tracker^™ to monitor therapy resistance during NeXT Personal MRD testing

FREMONT, Calif.--(BUSINESS WIRE)-- Personalis, Inc. (Nasdaq: PSNL), a leader in advanced genomics for precision oncology, announced today that an oral podium presentation featuring colorectal cancer data for the company’s NeXT Personal ultrasensitive ctDNA assay and three posters will be presented at the American Association for Cancer Research (AACR) Annual Meeting April 17-22, 2026, in San Diego, California.

A focus of this year’s data is the introduction of a new NeXT Personal MRD test option, Real-Time Variant Tracker, a first-of-its-kind feature in tumor-informed clinical MRD testing, designed to longitudinally track therapy resistance mutations.

"We are thrilled to present the first NeXT Personal data on the Real-Time Variant Tracker. The AACR data highlights how tracking therapy resistance mutations like ESR1 during MRD testing has the potential to inform patient management once cancer recurrence is detected," said Dr. Richard Chen, President and Chief Medical Officer at Personalis. “In addition, the data presented at AACR further reinforces that ultrasensitive ctDNA detection with NeXT Personal can impact how colorectal cancer is monitored and managed. Both of these studies are examples of our unwavering commitment to innovation to drive better outcomes for patients."

Presentations at AACR highlighting the use and clinical impact of the ultrasensitive NeXT Personal MRD test include:

Oral Podium Presentation: Neoadjuvant pembrolizumab stratified by tumor mutation burden in high-risk stage II-III dMMR/MSI colorectal cancer (NEOPRISM-CRC): Perioperative ultrasensitive ctDNA monitoring and tumor-infiltrating TCR repertoire for treatment response prediction.
Focus: Highlights the ultrasensitive ctDNA detection of NeXT Personal for predicting and tracking response to neoadjuvant immunotherapy in CRC patients.
Time: April 20, 2026, 2:35 PM–2:45 PM
Location: Room Hall H - Ground Level

Poster Presentation: Monitoring ESR1 and other mutations linked to resistance with a tumor-informed MRD test: Analytical validation and real world data.
Focus: Presents the analytical validation and real-world case studies of the new Real-Time Variant Tracker feature of NeXT Personal enabling detection of resistance and other clinical mutations during MRD testing.
Time: April 20, 2026, 9:00 AM–12:00 PM
Location: Section 46, Poster #2588

Poster Presentation: Enhancing MRD detection through an ultrasensitive ctDNA test: Insights from real-world clinical data.
Focus: A deep analysis of the real-world clinical performance of NeXT Personal across a large patient cohort. The data highlights the ability for NeXT Personal to consistently achieve ultrasensitive ctDNA detection levels below 100 parts per million (ppm) and 10 ppm, across a diverse set of solid tumor types, stages, and challenging real-world testing conditions.
Time: April 20, 2026, 2:00 PM–5:00 PM
Location: Section 45, Poster #8225

Poster Presentation: Ultrasensitive ctDNA monitoring predicts early response of immunotherapy in recurrent metastatic non-small cell lung cancer.
Focus: Demonstrates the performance of NeXT Personal for predicting relapse and outcomes in advanced NSCLC patients receiving immunotherapy.
Time: April 20, 2026, 2:00 PM–5:00 PM
Location: Section 45, Poster #3851

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 and can generally be identified by terms such as “believe,” “expect,” “if,” “may,” “will” or similar expressions. These statements include those relating to: the use, clinical impact or real-world clinical performance of NeXT Personal, the ability of NeXT Personal or the Real-Time Variant Tracker feature to inform cancer monitoring or patient management, predict or track therapy response, detect resistance or other clinical mutations, predict relapse, or predict or impact patient outcomes. 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 and the Real-Time Variant Tracker option, including the NeXT Personal MRD assay remaining unique in its ability to detect traces of cancer in the ultrasensitive range and its ability to monitor mutations; 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; 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 on February 26, 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.

Not affiliated with or endorsed by AACR.