Guardant wins FDA nod for diagnostic guiding use of AstraZeneca’s Etcamah

MedTech Guardant wins FDA nod for diagnostic guiding use of AstraZeneca’s Etcamah By Ben Adams Sep 7, 2026 2:08am Guardant Health AstraZeneca breast cancer Diagnostics Hot on the heels of the approval for AstraZeneca’s breast cancer drug Etcamah, Guardant Health has been given the green light for its companion diagnostic. On Sept. 4, AstraZeneca received U.S.

approval for its new drug in combination with a CDK4/6 inhibitor for patients with hormone receptor-positive, HER2-negative, locally advanced or metastatic breast cancer upon detection of an ESR1 mutation during aromatase inhibitor and CDK4/6 inhibitor therapy The drug’s use must be based on an FDA-authorized test, the company said. That test, approved the same day, is Guardant360 CDx, with repeat testing recommended every three months during therapy to detect emerging ESR1 mutations before clinical or radiographic progression. Related Guardant Health nabs FDA test approval to find patients for Boehringer’s new cancer drug Guardant said the approach represents a paradigm shift in biomarker testing in advanced cancer, where treatment changes have typically followed clinical or radiographic progression.

The testing giant said the approval shows a “fundamentally different approach,” as monitoring patients with its test during first-line therapy can help identify those developing resistance to treatment. In the Serena-6 trial, patients underwent serial Guardant360 CDx testing every three months while receiving an aromatase inhibitor with a CDK4/6 inhibitor. If an ESR1 mutation was detected before radiographic progression, eligible patients switched to camizestrant-based treatment.

“Patients treated under this new paradigm experienced 74% longer median progression-free survival (16 vs. 9.2 months) with a 47% reduction in risk of deterioration in global health status and quality of life,” Guardant said in a release. “This approval represents a landmark shift in how we define disease progression and reinforces the transformative role of liquid biopsy in guiding therapy decisions earlier at a critical moment in a breast cancer patient’s treatment journey,” said Helmy Eltoukhy, Guardant Health chairman and co-CEO, in a release.

Guardant Health AstraZeneca breast cancer Diagnostics MedTech