Guardant Health gains European CE mark for ESR1 breast cancer test
Guardant360 CDx can identify ESR1 mutations before progression in eligible advanced breast cancer; Guardant's Oct. 8 release gave no European payer terms.
Adrian Kessler
A European companion diagnostic label now covers blood testing for ESR1 mutations in advanced breast cancer after Guardant Health, Inc. NASDAQGH said on Thursday that Guardant360 CDx received CE marking for use with camizestrant. The Oct. 8 announcement calls this Guardant's 31st companion diagnostic approval and its third linked to the drug.
The intended use covers patients with estrogen receptor-positive, HER2-negative locally advanced or metastatic breast cancer who may benefit from ETCAMAH, the camizestrant treatment of AstraZeneca PLC NASDAQAZN. AstraZeneca's July 27 results also list camizestrant in its breast cancer program, while Guardant says its test can find ESR1 mutations from a blood draw before disease progression.
Guardant is a Palo Alto precision oncology company whose blood and tissue tests span cancer screening, recurrence monitoring and treatment selection across global markets.
Guardant shares closed at US$165.56 on Nasdaq on Thursday, according to NASDAQGH, as of 4:00:01 p.m. EDT.
The Release Omits European Payment Terms
Guardant said in its Oct. 8 release that the same test and treatment pairing had already won companion diagnostic approvals in the United States and Japan. The European CE mark adds another geography to that pairing, but the release gives neither a forecast of European test orders nor a reimbursement decision or payment rate for the new use.
That leaves a measurable question for shareholders: whether oncologists order enough additional tests under the new label to lift the oncology business beyond its existing growth plan. The announcement establishes the specified clinical use; it does not attach a patient count, a price per test or a schedule for national payer decisions.
"Guardant360 CDx offers molecular insights that can support informed treatment decisions for patients with advanced breast cancer, addressing the disease before it gets out of control," Guardant chairman and co-CEO Helmy Eltoukhy said in the Oct. 8 release.
Guardant reported about 104,000 oncology tests in the quarter ended June 30, up 63 per cent from a year earlier. Oncology revenue reached US$219.1 million in that quarter, up from US$158.7 million a year earlier, according to the same July 30 report. Those totals cover the broader oncology portfolio, rather than European camizestrant testing alone.
The company raised its forecast for 2026 oncology test volume growth to approximately 50 per cent from approximately 35 per cent in its July 30 results. The European label came after that forecast; Guardant's Thursday release does not assign it a separate sales contribution.
Another Listed Test Maker Tracks ESR1
Tempus AI, Inc. NASDAQTEM also lists ESR1 resistance mutations in breast cancer among the targets its xF and xF+ liquid biopsy panels can monitor. Its product page, reviewed Oct. 9, describes blood-based mutation testing but does not claim a European camizestrant companion diagnostic indication. That makes Tempus a relevant testing peer without equating its product's regulatory status with Guardant's newly marked use.
Guardant's Oct. 8 announcement establishes the European indication, while its July 30 accounts give the existing oncology test-volume baseline. The announcement provides no European camizestrant order or reimbursement figures.
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Guardant's 2026 guidance period ends Dec. 31. Its next full-year oncology test count will show whether volume growth approaches the roughly 50 per cent forecast in July, while any European camizestrant orders or payer terms will need separate disclosure to be measured.
