Blood-Based Multi-Cancer Test Sets New Standard for Ultra-Sensitive and Early MRD Detection

Detecting minimal residual disease (MRD) and early recurrence in cancer patients remains a major clinical challenge, particularly for those with early-stage breast cancer. Despite curative-intent treatment, up to 25% of patients, especially those with estrogen receptor-positive (ER+) tumors, will eventually experience recurrence, often years later. Now, a first-of-its-kind, blood-based multi-cancer MRD platform that tracks structural variants (SVs) offers ultra-sensitive and specific detection of cancer recurrence.

Pathlight from SAGA Diagnostics (Morrisville, NC, USA) operates by leveraging structural variants, tumor- and patient-specific genomic features such as breakpoints and rearrangements, as highly informative biomarkers. These SVs are identified through whole-genome sequencing and proprietary informatics designed to detect stable SV breakpoints, creating a personalized genomic fingerprint for each patient’s tumor. These fingerprints are then orthogonally validated and tracked using SAGA’s proprietary multiplex digital PCR system, which allows precise, rapid, and quantitative MRD detection from a simple blood draw. The method offers unprecedented sensitivity, breaking the 1 part per million (ppm) barrier, to detect MRD as early as possible. The clinical validity of Pathlight was established in the TRACER study (cTdna evaluation in eaRly breAst canCER), published in Clinical Cancer Research. The retrospective analysis included 100 patients with stage I–III breast cancer of all subtypes undergoing standard neoadjuvant and adjuvant therapy.

Image: Pathlight is a tumor-informed, multi-cancer MRD platform with its first indication in breast cancer (Photo courtesy of SAGA Diagnostics)

Pathlight demonstrated 100% sensitivity and 100% specificity, with a 13.7-month lead time to recurrence confirmed by imaging or clinical symptoms. The test also achieved a baseline detection rate of 96% overall and 94% in ER+ breast cancer, suggesting significant advantages over first-generation circulating tumor DNA (ctDNA) assays. SAGA Diagnostics has announced the U.S. commercial launch of its Pathlight test for the detection of residual disease and recurrence. With analytical validation across multiple cancer types, Pathlight is already in use in clinical studies by top pharmaceutical companies and major cancer centers. Its personalized, off-the-shelf design makes it a powerful surveillance tool for long-term monitoring and individualized intervention, with potential use across both solid tumors and hematologic malignancies.

“By tracking structural variants — stable, unique, and tumor-defining fingerprints of each patient’s cancer — Pathlight enables interception of recurrence at its most treatable and potentially curable stage,” commented Roopom Banerjee, Executive Chairman of SAGA Diagnostics. “Our goal is to deliver the most accurate, trusted results that provide assurance and support confident, informed treatment decisions. Our published, peer reviewed data demonstrates the clinical validity of Pathlight in breast cancer and its potential power across all solid tumors and heme malignancies. SAGA has further partnered with leading clinicians, institutions, and biopharma to bring Pathlight to market and best serve patients.”

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