SERENA-6
Trial question
What is the effect of camizestrant in patients with ER+, HER2- advanced breast cancer with an ESR1 mutation that emerged during treatment?
Study design
Multi-center
Double blinded
RCT
Population
Characteristics of study participants
99.0% female
1.0% male
N = 315
315 patients (312 female, 3 male).
Inclusion criteria: adult patients with ER+, HER2- advanced breast cancer with an ESR1 mutation that emerged during treatment.
Key exclusion criteria: advanced, symptomatic, or visceral spread at risk of life-threatening complications in the short term; active uncontrolled or symptomatic CNS metastases, carcinomatous meningitis, or leptomeningeal disease; severe or uncontrolled systemic disease which makes it undesirable for the patient to participate in the study; known or family history of severe heart disease; pregnancy or lactation.
Interventions
N=157 camizestrant (switch to camizestrant 75 mg once daily with a continued CDK 4/6 inhibitor plus placebo in place of an aromatase inhibitor).
N=158 aromatase inhibitor (continued receipt of an aromatase inhibitor plus a CDK 4/6 inhibitor plus placebo in place of camizestrant).
Primary outcome
Median progression-free survival
16 months
9.2 months
16.0 months
12.0 months
8.0 months
4.0 months
0.0 months
Camizestrant
Aromatase
inhibitor
Significant
increase ▲
Significant increase in median progression-free survival (16 months vs. 9.2 months; HR 2.27, 95% CI 1.67 to 3.23).
Secondary outcomes
Significant increase in median time until a deterioration in the patient-reported global health status and QoL (23 months vs. 6.4 months; HR 1.89, 95% CI 1.22 to 3.03).
Significant increase in second progression-free survival (75.8% vs. 70.3%; HR 1.92, 95% CI 1.23 to 3.03).
Safety outcomes
No significant differences in serious adverse events, adverse events leading to treatment discontinuation.
Conclusion
In adult patients with ER+, HER2- advanced breast cancer with an ESR1 mutation that emerged during treatment, camizestrant was superior to aromatase inhibitor with respect to median progression-free survival.
Reference
François-Clément Bidard, Erica L Mayer, Yeon Hee Park et al. First-Line Camizestrant for Emerging ESR1-Mutated Advanced Breast Cancer. N Engl J Med. 2025 Jun 1. Online ahead of print.
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