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SERENA-6 visual patient-reported outcomes & safety: camizestrant for emerging ESR1m advanced breast cancer during first-line endocrine-based therapy

In brief

Camizestrant adds visual side effects in 32% vs 16% with aromatase inhibitor

In the SERENA-6 phase III trial of 315 patients with ESR1-mutated advanced breast cancer, short-lived visual adverse events occurred in about one-third of those switched to camizestrant + CDK4/6 inhibitor versus one-sixth on standard aromatase inhibitor + CDK4/6 inhibitor; 90% were mild and none required stopping therapy. Vision acuity and eye structure were unchanged, and patient-reported functioning remained stable, suggesting the visual effects are reversible and clinically manageable.

Journal
The oncologist (Q1)
Published
24 July 2026
Study design
Randomized controlled trial
Evidence level
Level 1, High (CEBM 1b)
Authors
Adam Brufsky, Yeon Hee Park, François-Clément Bidard, Erica L Mayer, Wolfgang Janni, Cynthia Ma, et al.
PMID
42496653
DOI
10.1093/oncolo/oyag278

Why clinicians should know about it

  • Picked for Ophthalmology (top studies of the week, 26 July 2026): High-quality evidence in a top journal

Abstract

BACKGROUND: We report ophthalmological assessments, patient-reported visual symptoms/functioning, and characterization of visual effect AEs from the SERENA-6 study. MATERIALS AND METHODS: This double-blind, placebo-controlled phase III study included 315 patients with ER-positive advanced breast cancer receiving first-line aromatase inhibitor (AI)+CDK4/6 inhibitor (CDK4/6i). Patients with emerging ESR1 mutations in ctDNA and no radiological progression were randomized 1:1 to switch to camizestrant+CDK4/6i or continue AI+CDK4/6i. Predefined group term visual effect AEs were graded (NCI-CTCAE v5.0). Ophthalmologic assessments were conducted at baseline, as indicated, and end-of-treatment. Analyses of patient-reported visual effects/functioning were exploratory. RESULTS: Visual effect AEs were reported in 49 (31.6%) patients receiving camizestrant+CDK4/6i and 25 (16.1%) patients receiving AI+CDK4/6i; 90% were grade 1; none led to discontinuation. No changes in visual acuity or ocular structure were observed. Patient-reported visual effects occurred early (by week 2) and were reversible post-treatment. The proportion of patients in the camizestrant+CDK4/6i and AI+CDK4/6i arm reporting short-lived visual effects (<1min) ranged from 60%-67% vs 50%-69%, respectively; visual effects causing no/a low degree of bother: 78%-88% vs 50%-75%, respectively. During treatment, visual functioning was comparable to baseline and between arms. CONCLUSION: If experienced, patient-reported visual effects (including photopsia) with camizestrant+CDK4/6i were short-lived and reversible post-treatment. Visual effect AEs with camizestrant+CDK4/6i were mostly mild and did not require treatment discontinuation or ophthalmologic management. There was no impact on ocular structure, function, or visual acuity; visual effects had little/no impact on daily functioning. These findings support clinical decision-making by further characterizing the visual safety profile of camizestrant in this setting. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT04964934.

Abstract as published, via PubMed.

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For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.