Ribociclib Plus Endocrine Therapy Versus Combination Chemotherapy for Aggressive Breast Cancer

By: Julia Fiederlein Cipriano
Posted: Friday, January 13, 2023

The CDK4/6 inhibitor ribociclib plus endocrine therapy demonstrated a statistically significant and clinically meaningful progression-free survival benefit versus standard-of-care combination chemotherapy in premenopausal and perimenopausal patients with hormone receptor–positive, HER2-negative advanced breast cancer, including those with visceral crises, according to Yen-Shen Lu, MD, PhD, of the National Taiwan University Hospital, Taipei, and colleagues. The primary results of the phase II RIGHT Choice trial, which were presented during the 2022 San Antonio Breast Cancer Symposium (SABCS; Abstract GS1-10), seemed to support this novel regimen as a preferred first-line option.

“Through the use of first-line ribociclib plus endocrine therapy, we may be able to avoid or delay chemotherapy and spare patients—even those with aggressive, life-threatening disease—the toxicities and discontinuations associated with chemotherapy,” commented Dr. Lu in a press release from the American Association for Cancer Research.

Patients were randomly assigned to receive either ribociclib plus an aromatase inhibitor—letrozole or anastrozole—and goserelin (n = 112) or the investigator’s choice of combination chemotherapy (n = 110; docetaxel plus capecitabine, paclitaxel plus gemcitabine, or capecitabine plus vinorelbine). Of the study population, 52.3% had visceral crises.

The median duration of progression-free survival was prolonged with ribociclib plus endocrine therapy versus combination chemotherapy (24.0 vs. 12.3 months; hazard ratio [HR] = 0.54; P = .0007). At data cutoff, the study remained immature for overall survival analysis. The median durations of time to treatment failure were 18.6 and 8.5 months with ribociclib plus endocrine therapy and combination chemotherapy, respectively (HR = 0.45). Similar overall response rates were observed between the arms (65.2% vs. 60.0%).

No new safety signals were identified in patients treated with ribociclib. Lower rates of treatment-related serious adverse events (1.8% vs. 8.0%) and treatment discontinuation due to treatment-related adverse events (7.1% vs. 23.0%) were observed with ribociclib plus endocrine therapy versus combination chemotherapy. The adverse events reported with combination chemotherapy were consistent with published data.

Disclosure: For full disclosures of the study authors, visit sabcs.org.

2022 San Antonio Breast Cancer Symposium

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