In patients with hormone receptor-positive advanced breast cancer with emergent ESR1 mutation while on first-line aromatase inhibitor plus CDK4/6 inhibitor, switching to camizestrant plus CDK4/6 inhibitor significantly improved progression-free survival and second progression-free survival compared to continuing aromatase inhibitor plus CDK4/6 inhibitor. This strategy also prolonged chemotherapy-free or antibody-drug conjugate-free survival and delayed time to deterioration in global health status and quality of life. The safety profile of camizestrant plus CDK4/6 inhibitor was well tolerated, with no new safety signals identified.
Study
|
Randomized, double-blind, placebo-controlled, phase 3 study [SERENA-6; NCT04964934] |
| Hormone receptor-positive, HER2-negative advanced breast cancer with emergent ESR1 mutation on first-line aromatase inhibitor plus CDK4/6 inhibitor without radiological progression |
| Camizestrant + CDK4/6 inhibitor (n=157) vs continued aromatase inhibitor + CDK4/6 inhibitor (n=158)
|
Efficacy
|
mPFS: 16.8 mos vs 9.2 mos (camizestrant + CDK4/6i vs. AI + CDK4/6i) (HR 0.45 [0.34-0.59]) |
| mPFS2: 25.7 mos vs 19.1 mos (HR 0.63 [0.46-0.86]) |
| Chemotherapy-free or ADC-free survival: 22.6 mos vs 18.7 mos (HR 0.64 [0.47-0.87]) |
| mOS: 41.2 mos vs 40.2 mos (HR 0.87 [0.57-1.30])
|
Safety
|
Grade >=3 AE: neutropenia (27% vs 17%) |
| Serious adverse events: 15% vs 19% |
| Discontinuation of camizestrant or aromatase inhibitor due to AE: 1% vs 3%
|
Lancet Oncol 2026;27:941-58
http://doi.org/10.1016/S1470-2045(26)00287-1
Reviewed by Ulas D. Bayraktar, MD on Aug 20, 2026
