On Sept. 4, 2026, the US Food and Drug Administration (FDA) granted accelerated approval to AstraZeneca’s Etcamah® (camizestrant – AstraZeneca), in combination with a cyclin-dependent kinase (CDK) 4/6 inhibitor (abemaciclib, palbociclib or ribociclib), for the treatment of adult patients who have hormone receptor-positive (HR+), human epidermal growth factor receptor 2 – negative (HER2-), locally advanced or metastatic breast cancer upon detection of an estrogen receptor-1 (ESR1) mutation during aromatase inhibitor (AI) and CDK4/6 inhibitor therapy, based on an FDA-authorized test. Etcamah is an oral, next-generation selective estrogen receptor degrader (SERD) and complete estrogen receptor antagonist that binds to the estrogen receptor and induces its degradation, blocking estrogen-driven tumor growth even when the receptor carries an ESR1 resistance mutation. This marks the first FDA approval of a cancer therapy guided by detection of a resistance mutation in circulating tumor DNA (ctDNA) before radiographic disease progression, allowing clinicians to switch therapy earlier. The FDA simultaneously approved Guardant Health’s Guardant360 CDx as the companion diagnostic used to identify eligible patients. The label recommends repeat Guardant360 CDx testing every three months during first-line AI plus CDK4/6 inhibitor therapy to detect an emerging ESR1 mutation via ctDNA before clinical or radiographic disease progression occurs, at which point a patient becomes eligible to switch to Etcamah. The recommended dose of Etcamah is 75mg taken orally once daily, with or without food, continued alongside the patient’s existing CDK4/6 inhibitor. US launch timing has not been announced, and pricing has not yet been disclosed. Here is the prescribing information.
At a Glance
- Brand Drug: Etcamah® (camizestrant)
- Manufacturer: AstraZeneca
- Date Approved: Sept. 4, 2026
- Indication: In combination with a CDK4/6 inhibitor (abemaciclib, palbociclib, or ribociclib) for the treatment of adult patients HR+/HER2-, locally advanced or metastatic breast cancer upon detection of ESR1 mutation during aromatase inhibitor and CDK4/6 inhibitor therapy, based on an FDA-authorized test.
- Dosage Forms Available: 75mg tablets
- Launch Date: Not yet known
- Estimated Annual Cost: Unknown
- FDA Designation: Accelerated approval.
- HR+, HER2- disease is the most common breast cancer subtype, representing roughly 70% of the more than 300,000 breast cancer cases and 42,000 deaths diagnosed annually in the US.
- ESR1 mutations emerge as a key mechanism of endocrine resistance, particularly following exposure to endocrine therapy and CDK4/6 inhibitors. This mutation is associated with disease progression and limited treatment options. It is present in fewer than 5% of patients at initial HR+ metastatic diagnosis but is emerging in up to 40% of patients following progression on an AI.
- Approval was based on the phase III SERENA-6 trial, which randomized 315 patients with a ctDNA-detected ESR1 mutation and no radiographic progression to switch to Etcamah plus their current CDK4/6 inhibitor or continue an AI plus CDK4/6 inhibitor. Median progression-free survival (PFS) was 16.0 months with Etcamah versus 9.2 months in the control group, a 56% reduction in the risk of disease progression or death.
- Unlike currently approved oral SERDs: Orserdu® (elacestrant – Menarini/Stemline), Inluriyo® (imlunestrant – Eli Lilly) and Veppanu® (vepdegestrant – Arvinas/Pfizer), which are all indicated after confirmed radiographic or clinical disease progression on endocrine therapy, Etcamah is the first oral SERD approved for use before progression is confirmed.
- The FDA’s Oncologic Drugs Advisory Committee (ODAC) voted 6-3 in April 2026 against recommending approval, questioning whether a ctDNA-guided treatment switch, rather than one triggered by radiographic or clinical progression, represents a clinically meaningful benefit. The FDA proceeded with an accelerated approval, requiring confirmatory trials to verify clinical benefit. Overall survival is continuing to be evaluated in SERENA-6.
- The label carries a boxed warning for arrhythmia with concomitant use of ribociclib or other QTc-prolonging drugs, along with warnings for bradycardia and embryo-fetal toxicity.
- Pipeline competition includes Genentech’s giredestrant, with an FDA action date of Dec. 18, 2026, for later-line ER-positive/HER2-negative disease, and Olema Pharmaceuticals’ palazestrant, in phase III development with a potential approval around 2027.
- Guardant Health’s Guardant360® CDx companion diagnostic approval for Etcamah, makes it the first FDA-approved liquid biopsy (blood-based) test for longitudinal monitoring in breast cancer.