ESR1 and breast carcinoma: Similarly, among patients with detectable ESR1-mutant breast cancer, patients treated with elacestrant had better PFS compared to those receiving standard endocrine therapy, irrespective of past fulvestrant treatment: fulvestrant-treated, 6 months PFS = 34.06% on elacestrant (n=27) vs 12.11% on standard endocrine therapy (n=28), HR: 0.679; fulvestrant-naïve: PFS rate at 6 months= 42.42% on elacestrant (n=88) vs 20.95% on standard endocrine therapy (n=85), HR = 0.513; (Fig. 1C, D).