BillionToOne’s Tissue-Free Northstar Response® Demonstrates On-Par to Superior Cancer Treatment Monitoring vs. Tumor-Informed Assay, New Peer-Reviewed Study Finds

In all divergent cases, Northstar Response results matched clinical findings supported by imaging and/or biopsy.

Rhea-AI Summary

BillionToOne (BLLN) announced a peer-reviewed study comparing its Northstar Response blood test with a tumor-informed assay for advanced cancer treatment monitoring. Published in The Journal of Liquid Biopsy, the retrospective study evaluated 169 paired samples from 61 patients. A subset included 71 samples from 36 patients with sequential concurrent blood draws collected within seven days of each other.

The assays agreed on the direction of tumor burden change in 94% of evaluable sequential pairs (67 of 71). In all divergent cases, Northstar Response matched findings supported by imaging and/or biopsy. Quantitative results across repeated measurements were closely aligned after patient-specific baseline normalization, with conditional R² of 0.97. Northstar Response measures circulating tumor DNA—DNA shed by tumors into blood—without requiring tissue sequencing.

Positive

• Minor point94% agreement (67 of 71) on tumor burden direction across evaluable sequential pairs supports comparative monitoring performance.
• Minor pointAll divergent cases showed Northstar Response results consistent with imaging and/or biopsy findings.
• Minor pointConditional R² of 0.97 showed closely aligned repeated quantitative measurements after patient-specific baseline normalization.

Negative

• Minor pointRetrospective study design limits the findings to the evaluated real-world samples from 61 patients.

News Explained

The company says Northstar Response is a laboratory-developed test performed in a CLIA-certified, CAP-accredited lab, not cleared or approved by the FDA; results should complement, not replace, clinical and radiographic assessment and should not be the sole basis for medical decisions.

Key Figures

Study cohort: 169 paired samples; 61 patients Sequential concurrent-draw subset: 71 samples; 36 patients Conditional R²: 0.97 +1 more

Study cohort

169 paired samples; 61 patients

Retrospective real-world study

Sequential concurrent-draw subset

71 samples; 36 patients

Draws for the two assays collected within seven days

Conditional R²

0.97

Quantitative results after patient-specific baseline normalization

Tumor-burden direction concordance

94% (67 of 71)

Evaluable sequential pairs

Key Terms

ctDNA, conditional R², laboratory-developed test (LDT)

3 terms

ctDNA medical

"circulating tumor DNA (ctDNA) molecules"

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.

conditional R² technical

"conditional R² = 0.97"

Conditional R² is a measure of explained variance used with mixed-effects (multilevel) regression models that shows the proportion of total outcome variance accounted for by the entire model — both fixed effects (predictors with estimated coefficients) and random effects (group-level or subject-level components). It is calculated by comparing the model-implied variance of the predicted values (including random-effect variance) to the total variance (predicted variance plus residual variance). Distinction: conditional R² differs from marginal R², which reports only the variance explained by the fixed effects and omits the contribution of random effects.

laboratory-developed test (LDT) regulatory

"a laboratory-developed test (LDT) performed in a CLIA-certified"

A laboratory-developed test (LDT) is a diagnostic test that a single clinical laboratory designs, builds and uses on-site rather than buying as a finished product from a manufacturer — think of it like a restaurant’s house recipe served only at that location. Investors should care because LDTs can drive a lab’s revenue and competitive edge but also carry unique regulatory, reimbursement and scalability risks that affect future growth and valuation.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Head-to-head comparison shows 94% concordance with tumor-informed ctDNA testing, with the clinical ground-truth in all discordant cases supporting Northstar Response

MENLO PARK, Calif., Oct. 07, 2026 (GLOBE NEWSWIRE) -- BillionToOne, Inc. (Nasdaq: BLLN), a next-generation molecular diagnostics company with a mission to create powerful and accurate tests that are accessible to all, announced the publication of the first peer-reviewed head-to-head study comparing Northstar Response®, a tissue-free, methylation-based liquid biopsy assay utilizing patented single-molecule counting technology to measure the absolute number of circulating tumor DNA (ctDNA) molecules, with a commercially available tumor-informed ctDNA assay for advanced cancer patients undergoing treatment. The study found that Northstar Response tracked disease dynamics on par with or better than the tumor-informed comparator, without requiring tissue sequencing.

The retrospective real-world study, published in The Journal of Liquid Biopsy, evaluated 169 paired samples from 61 patients, with 71 samples from 36 patients that had sequential concurrent draws for the two assays collected within seven days of each other. Quantitative results, after patient-specific baseline normalization, across repeated measurements were shown to be closely aligned (conditional R² = 0.97). Across evaluable sequential pairs, the two approaches reached the same conclusion of the change in tumor burden direction in 94% of cases (67 of 71).

Importantly, in all of the divergent cases, Northstar Response results were concordant with the ground truth substantiated by imaging and/or biopsy, indicating that the tumor-informed results were either false-positives or false-negatives. For instance, Northstar Response detected progression in cases where the tumor had evolved since the original biopsy, including a case of hormone receptor conversion in advanced breast cancer. Together, the cases illustrate the particular value of tumor-agnostic monitoring to track tumor burden and evolution.

"The ability to combine cancer-associated methylation with single-molecule precision to track changing tumor signal directly from blood is game-changing, as so many patients in the clinic will benefit," said Vaia Florou, MD, MS, Associate Professor Division of Oncology at the Huntsman Cancer Institute at the University of Utah. "These results showing that a standardized assay can deliver precise longitudinal monitoring without tissue dependency are incredibly relevant for those of us practicing on the frontlines of cancer care."

Since Northstar Response is not limited to alterations selected from an earlier tissue sample at a fixed point in time, it can capture clinically meaningful changes in disease biology that emerge under treatment pressure. Northstar Response’s simplified workflow can also significantly accelerate the start of molecular monitoring of treatment, potentially by weeks, and enable testing when tissue is unavailable, inadequate, or difficult to biopsy.

“Not only does Northstar Response deliver highly accurate insight into how disease is evolving during treatment, but it also has the added advantage of a streamlined and efficient workflow that can bring molecular testing to more patients,” said Allen Chen, MD, Vice President of Oncology Clinical Development and Medical Affairs at BillionToOne. “Treatment monitoring must be both reliable and practical for it to be effective in routine oncology care. These results show that clinicians do not need to compromise one for the other.”

About Northstar Response

Northstar Response is BillionToOne's tissue-free, methylation-based ctDNA assay purpose-built for treatment response monitoring in patients with cancer. Powered by the company's patented QCT™ molecular counting platform -- the only multiplex technology capable of counting DNA molecules at the single-molecule level -- Northstar Response quantifies tumor burden through serial blood draws with no dependence on tumor tissue at any stage of the patient journey.

About BillionToOne

Headquartered in Menlo Park, California, BillionToOne is a next-generation molecular diagnostics company with a mission to create powerful and accurate tests that are accessible to all. The company's proprietary single-molecule next-generation sequencing (smNGS) platform is the only multiplex technology that can detect and precisely quantify genetic targets at the physical limit of detection, down to the single DNA molecule. Enabled by Quantitative Counting Templates™ (QCTs™), the platform quantifies disease-related DNA fragments with single base-pair resolution, providing absolute quantification. For more information, visit www.billiontoone.com.

Disclaimer

Northstar Response may produce false-positive or false-negative results. Test results are not a guarantee of the presence or absence of disease or treatment response and should not be used as the sole basis for medical decision-making. Results should be interpreted in conjunction with the patient's clinical presentation, radiographic findings, and other diagnostic information. Northstar Response is intended to complement, not replace, standard clinical and radiographic assessment of disease status. Northstar Response is a laboratory-developed test (LDT) performed in a CLIA-certified and CAP-accredited laboratory. The test has not been cleared or approved by the U.S. Food and Drug Administration (FDA). Test performance may vary based on factors including cancer type, disease burden, treatment, and specimen characteristics.

Forward-Looking Statements

This press release contains certain forward-looking statements within the meaning of federal securities laws. These forward-looking statements generally are identified by the words “believe,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “strategy,” “future,” “opportunity,” “plan,” “may,” “should,” “will,” “would,” “will be,” “will continue,” “will likely result,” and similar expressions. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Forward-looking statements in this press release include, but are not limited to, statements regarding the clinical performance of Northstar Response. These statements are based on management’s current expectations, forecasts and assumptions, and actual outcomes and results could differ materially from these statements due to a number of factors, some of which are beyond BillionToOne’s control. These and additional risks and uncertainties could affect BillionToOne’s financial and operating results and cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. These risks and uncertainties include, but are not limited to, those discussed under the captions “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operation” and elsewhere in BillionToOne’s Annual Report on Form 10K, most recently filed Quarterly Report on Form 10-Q, and other filings we make with the Securities and Exchange Commission from time to time. The forward-looking statements in this press release are based on information available to BillionToOne as of the date hereof, and BillionToOne disclaims any obligation to update any forward-looking statements provided to reflect any change in its expectations or any change in events, conditions, or circumstances on which any such statement is based, except as required by law. These forward-looking statements should not be relied upon as representing BillionToOne’s views as of any date subsequent to the date of this press release.

Reference

Choksi A, Varga MG, Farmer T, et al. Concordance of tumor-informed and tumor-agnostic ctDNA assays for treatment response monitoring in advanced solid tumors. The Journal of Liquid Biopsy. Volume 14, 2026, 100669.

Media Contact

Rachel Ford Hutman
rachel@fordhutmanmedia.com

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did BillionToOne's Northstar Response comparison study find?

The assays agreed on tumor burden direction in 94% of evaluable sequential pairs (67 of 71). In all divergent cases, Northstar Response matched clinical findings supported by imaging and/or biopsy. Repeated quantitative measurements were closely aligned after patient-specific baseline normalization, with conditional R² of 0.97.

How many patients were included in BillionToOne's Northstar Response study?

The retrospective study evaluated 169 paired samples from 61 patients. It included 71 samples from 36 patients with sequential concurrent draws for both assays collected within seven days of each other.

Can Northstar Response results alone guide cancer treatment decisions?

Northstar Response results should not be the sole basis for medical decision-making. The test may produce false-positive or false-negative results and is intended to complement, not replace, standard clinical and radiographic assessment. Results should be interpreted alongside the patient's clinical presentation, imaging findings and other diagnostic information.