{"entity":{"id":"foundationone-mrd","kind":"drug","name":"FoundationOne MRD","aka":["Pathlight","Pathlight MRD","SAGA Pathlight"],"tldr":"Foundation Medicine's blood test for breast cancer coming back, launched in May 2026; it is SAGA Diagnostics' Pathlight test, which Medicare already covered.","summary":"FoundationOne MRD is Foundation Medicine's residual disease test, launched on 29 May 2026 after Roche completed its acquisition of SAGA Diagnostics, which Foundation Medicine had announced on 16 April 2026 at up to 595 million dollars including milestones. It is SAGA's Pathlight test under a new name and is performed by SAGA Diagnostics US. Instead of point mutations it tracks structural variants found by whole-genome sequencing of the tumour, measured in blood by digital PCR. Foundation Medicine states that it is intended for recurrence monitoring in stage II-III breast cancer and is covered by Medicare for recurrence monitoring in the surveillance setting for up to six years in that group; the Medicare coverage was first issued for Pathlight on 30 July 2025, across HR-positive/HER2-negative, HER2-positive and triple-negative subtypes. It is a laboratory-developed test that has not been cleared or approved by the FDA, and Foundation Medicine notes it is not approved by New York State.","status":"emerging","asOf":"2026-11-03","links":[{"label":"Foundation Medicine: FoundationOne MRD","url":"https://www.foundationmedicine.com/solution/foundationone-mrd"},{"label":"Foundation Medicine launches FoundationOne MRD (29 May 2026)","url":"https://www.foundationmedicine.com/press-release/foundationone-mrd"},{"label":"Foundation Medicine: Roche to acquire SAGA Diagnostics (16 April 2026)","url":"https://www.foundationmedicine.com/press-release/saga-diagnostics-mrd-platform"},{"label":"SAGA Diagnostics: Medicare coverage for Pathlight in breast cancer (30 July 2025)","url":"https://sagadiagnostics.com/saga-diagnostics-announces-medicare-coverage-for-pathlight-mrd-test-in-breast-cancer-across-all-subtypes/"},{"label":"Natera and Foundation Medicine: FoundationOne Tracker launch and Medicare coverage (10 October 2023)","url":"https://www.natera.com/company/news/foundation-medicine-and-natera-announce-broad-clinical-launch-and-medicare-coverage-of-foundationonetracker/"},{"label":"Elliott et al., structural-variant ctDNA detection in early breast cancer (Clinical Cancer Research 2025)","url":"https://doi.org/10.1158/1078-0432.CCR-24-3472"},{"label":"CMS MolDX billing article A58376: minimal residual disease testing for solid tumour cancers","url":"https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=58376"}],"tags":["test"],"related":["signatera","next-personal","foundationone-cdx"],"cancers":["breast-cancer","breast-hr-positive","breast-her2-positive","tnbc"],"sections":[],"technologies":["mrd-testing","liquid-biopsy","wes-wgs"],"targets":[],"drugs":[],"companies":["foundation-medicine"],"institutions":[],"pathways":[],"terms":["mrd","ctdna","tumour-informed-assay"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["What a result means: a positive result during surveillance suggests the breast cancer is returning before it shows on a scan; a negative one is reassuring but not a guarantee.","Foundation Medicine's earlier monitoring test, FoundationOne Tracker, built with Natera on FoundationOne CDx results, launched broadly on 10 October 2023 for monitoring response to treatment in advanced cancer, with Medicare coverage from 17 June 2023 for monitoring immune checkpoint inhibitor therapy. It was a treatment-response test, not an MRD test, and on 3 November 2026 its page no longer appeared on Foundation Medicine's site; whether it is still offered was not confirmed.","The performance figures on the product page come from the TRACER study, where the analysis of distant recurrence was limited to 17 patients. The exact closing date of the SAGA acquisition was not stated."],"brand":"FoundationOne MRD","modality":"Tumour-informed ctDNA minimal residual disease test (whole-genome design, digital PCR of up to 16 structural variants)","mechanism":"Whole-genome sequencing of the tumour finds structural variants, rearrangements of the tumour's DNA, and a customised multiplex digital PCR fingerprint of up to 16 of them is then measured in plasma.","approvals":[],"mechanismSteps":[],"toxicity":[],"access":[{"country":"US","reimbursement":"Medicare covers it for recurrence monitoring in stage II-III breast cancer, all subtypes: HR-positive/HER2-negative breast cancer, HER2-positive breast cancer and triple-negative breast cancer (coverage first issued for SAGA Diagnostics' Pathlight on 30 July 2025)","source":"https://sagadiagnostics.com/saga-diagnostics-announces-medicare-coverage-for-pathlight-mrd-test-in-breast-cancer-across-all-subtypes/","asOf":"2026-11-03"}],"regulatoryEvents":[]},"route":"/drugs/foundationone-mrd/","neighbours":{"drug":[{"id":"foundationone-cdx","kind":"drug","name":"FoundationOne CDx / Liquid CDx","route":"/drugs/foundationone-cdx/"},{"id":"next-personal","kind":"drug","name":"NeXT Personal Dx","route":"/drugs/next-personal/"},{"id":"signatera","kind":"drug","name":"Signatera","route":"/drugs/signatera/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"breast-her2-positive","kind":"cancer","name":"HER2-positive breast cancer","route":"/cancers/breast-her2-positive/"},{"id":"breast-hr-positive","kind":"cancer","name":"HR-positive / HER2-negative breast cancer","route":"/cancers/breast-hr-positive/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"technology":[{"id":"liquid-biopsy","kind":"technology","name":"Liquid biopsy (ctDNA)","route":"/technologies/liquid-biopsy/"},{"id":"mrd-testing","kind":"technology","name":"MRD / molecular residual disease testing","route":"/technologies/mrd-testing/"},{"id":"wes-wgs","kind":"technology","name":"Whole-exome & whole-genome sequencing","route":"/technologies/wes-wgs/"}],"company":[{"id":"foundation-medicine","kind":"company","name":"Foundation Medicine (Roche)","route":"/companies/foundation-medicine/"}],"term":[{"id":"ctdna","kind":"term","name":"Circulating tumour DNA (ctDNA)","route":"/terms/ctdna/"},{"id":"mrd","kind":"term","name":"Minimal / molecular residual disease (MRD)","route":"/terms/mrd/"},{"id":"tumour-informed-assay","kind":"term","name":"Tumour-informed versus tumour-naive ctDNA assays","route":"/terms/tumour-informed-assay/"}],"roadmap":[{"id":"ctdna-tests","kind":"roadmap","name":"ctDNA tests roadmap: from a curiosity in plasma to blood tests that decide treatment","route":"/roadmaps/ctdna-tests/"},{"id":"diagnostics-roadmap","kind":"roadmap","name":"Diagnostics roadmap: stains → gene panels → blood tests that decide treatment","route":"/roadmaps/diagnostics-roadmap/"}],"biomarker":[{"id":"ctdna-mrd-positive","kind":"biomarker","name":"ctDNA MRD positivity (molecular residual disease after curative treatment)","route":"/biomarkers/ctdna-mrd-positive/"}]}}