In the randomized multicenter phase 2 trial SERENA-2 (ClinicalTrials.gov identifier: NCT04214288), the efficacy and safety profiles of oral camizestrant were compared with fulvestrant; camizestrant substantially improved progression-free survival (PFS) versus fulvestrant in post-menopausal patients with ER+ advanced breast cancer who had previously been treated with endocrine therapy. The gene discussed is ESR1; the disease is breast cancer.