MONALEESA3

MONALEESA3 is a clinical trial that investigated the efficacy and safety of ribociclib in combination with fulvestrant for the treatment of postmenopausal women with hormone receptor-positive, HER2-negative advanced or metastatic breast cancer. Ribociclib is a cyclin-dependent kinase (CDK) 4/6 inhibitor, and fulvestrant is a selective estrogen receptor degrader. The primary endpoint of the MONALEESA3 trial was progression-free survival (PFS).

The trial enrolled patients who had received no prior therapy for advanced disease or who had relapsed within 12 months of completing adjuvant endocrine therapy. Participants were randomized to receive either ribociclib plus fulvestrant or placebo plus fulvestrant. The study demonstrated a statistically significant improvement in PFS for patients treated with the combination of ribociclib and fulvestrant compared to placebo and fulvestrant.

Key findings from MONALEESA3 included a reduction in the risk of disease progression or death. The safety profile of the combination therapy was consistent with previous studies of ribociclib and fulvestrant, with the most common adverse events being neutropenia, fatigue, and nausea. The results of MONALEESA3 contributed to the established role of CDK4/6 inhibitors in combination with endocrine therapy as a standard of care for this patient population. The trial provided further evidence supporting the benefit of this combination in both first-line and second-line settings for advanced breast cancer.