Multinational randomized phase 2 trial of camizestrant versus fulvestrant for postmenopausal ER-positive, HER2-negative advanced breast cancer

Camizestrant is a next-generation oral selective estrogen receptor degrader (SERD) and complete estrogen receptor antagonist. The multinational randomized phase 2 SERENA-2 trial compared camizestrant once daily at 75 mg or 150 mg versus the first approved SERD fulvestrant for postmenopausal ER-positive, HER2-negative advanced breast cancer. The median progression-free survival was 7.2 months (90% CI 3.7-10.9) with camizestrant 75 mg and 7.7 months (5.5-12.9) with camizestrant 150 mg, versus 3.7 months (2.0-6.0) with fulvestrant. The HR for camizestrant 75 mg versus fulvestrant was 0.59 (p=0.017) and the HR for camizestrant 150 mg versus fulvestrant was 0.64 (p=0.009). Treatment-related adverse events occurred in 53% of patients with camizestrant 75 mg and 67% of patients with camizestrant 150 mg, versus 18% of patients with fulvestrant. No single grade 3 or worse TRAE occurred in more than 3% of patients in any group. No treatment-related deaths occurred. The author conclude that camizestrant at 75 and 150 mg showed a significant benefit in progression-free survival versus fulvestrant.