FDA Camizestrant Approval: Nurses Key to New Breast Cancer Paradigm

The US Food and Drug Administration (FDA) granted accelerated approval to the oral selective estrogen receptor degrader (SERD) camizestrant (Etcamah) in combination with a cyclin-dependent kinase (CDK) 4/6 inhibitor (abemaciclib, palbociclib, or ribociclib) for adult patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer.

The approval applies to patients whose tumors harbor an emerging estrogen receptor-1 (ESR1) mutation during first-line aromatase inhibitor (AI) and CDK4/6 inhibitor therapy, detected by an FDA-authorized test. This approval marks a shift from reactive progression monitoring to active, molecularly guided interception.

Historically, advanced breast cancer is monitored via radiographic scans, with systemic therapy changed only upon visible clinical or radiologic disease progression. The Phase III SERENA-6 trial (NCT04964934) established a different paradigm: serial circulating tumor DNA (ctDNA) blood monitoring is performed alongside routine scans to detect the emergence of an ESR1 resistance mutation prior to objective progression.

Patients in the trial with an emergent ESR1 mutation who switched preemptively to oral camizestrant achieved a median progression-free survival of 16.0 months compared with 9.2 months for those who remained on standard AI therapy (hazard ratio, 0.44; 95% CI, 0.31-0.60; p < 0.0001).

According to Erica L. Mayer, MD, MPH, of the Dana-Farber Cancer Institute and US lead investigator for SERENA-6, this strategy represents a new framework for monitoring advanced breast cancer.

Oncology nursing teams will be central to communicating the clinical value of this preemptive switch and managing the clinical logistics of serial ctDNA blood draws.

A concern among clinicians is whether early detection of a resistance mutation will heighten patient anxiety. However, Mayer noted that patients in the trial had the opposite experience, as patients welcomed this precise, proactive method of monitoring, finding it empowering rather than frightening because it allowed clinical teams to act on early resistance data. Nurses can reassure patients that a positive ctDNA test does not indicate immediate clinical treatment failure, but serves as a molecular warning that enables precise backbone treatment changes.

In addition to extending disease control, the camizestrant switch delayed the deterioration of patient-reported quality of life. The median time to quality-of-life deterioration was 21.0 months with camizestrant versus 6.4 months with an AI (hazard ratio, 0.54; 95% CI, 0.34-0.84). Preemptive intervention also delayed the need for cytotoxic chemotherapy or antibody-drug conjugates, with low discontinuation rates due to adverse events (1.3% vs 1.9%).

To ensure patient safety, oncology nurses must monitor for risks detailed in the prescribing information, which includes a boxed warning for arrhythmia due to QTc interval prolongation, alongside warnings for bradycardia and embryo-fetal toxicity. Nurses must screen concomitant medications for drug-drug interactions and monitor electrocardiograms and heart rates to support safe adherence to the recommended dose of 75 mg once daily.

References

1. Food and Drug Administration. FDA grants accelerated approval to camizestrant with a CDK4/6 inhibitor for ESR1-Mutated HR-positive, HER2-negative locally advanced or metastatic breast cancer. FDA. Published September 4, 2026. Accessed September 8, 2026.
2. Bidard FC, Mayer EL, Park YH, et al. First-line camizestrant for emerging ESR1-mutated advanced breast cancer. N Engl J Med. 2025;393(6):569-580.
3. Bidard FC, Barrios C, Bianchini G, et al. SERENA-6 interpretation and clinical implications: intercepting endocrine resistance in metastatic breast cancer. NPJ Breast Cancer. 2026;12(1):18.