A first prospective, head-to-head study showed superior progression-free survival of ribociclib plus endocrine therapy over combination chemotherapy in patients with aggressive HR-positive/HER2-negative advanced breast cancer.


In patients with advanced breast cancer with aggressive disease features, like rapidly progressing or highly symptomatic disease, including life-threatening visceral crisis, combination chemotherapy is the standard-of-care.1 Ribociclib plus endocrine therapy demonstrated statistically significant progression-free and overall survival benefits over endocrine therapy alone in several clinical trials in patients with HR-positive/HER2-negative advanced breast cancer, including patients with visceral metastases and a high tumor burden.2-4

The phase 3, RIGHT Choice trial compared the efficacy and safety of ribociclib plus endocrine therapy versus combination chemotherapy in patients with aggressive HR-positive/HER2-negative advanced breast cancer. Dr. Yen-Shen Lu (National Taiwan University Hospital, Taiwan) presented the primary results5 at the 2022 San Antonio Breast Cancer Symposium.

A total of 222 patients with no prior systemic treatment for advanced breast cancer were randomized 1:1 to receive ribociclib plus letrozole or anastrozole versus a physicians’ choice combination chemotherapy (docetaxel/capecitabine, paclitaxel/gemcitabine, or capecitabine/vinorelbine). The primary endpoint was progression-free survival (PFS).

After a median duration of 24 months, 45.5% of patients in the ribociclib arm and 23.6% of patients in the chemotherapy arm were still on treatment. Median PFS was 24.0 months for patients treated with ribociclib plus endocrine therapy, compared with 12.3 months for patients treated with combination chemotherapy (HR, 0.54; P=0.0007). PFS benefit of ribociclib plus endocrine therapy was observed across most patient subgroups. The median time to treatment failure was longer in the ribociclib arm (18.6 months vs 8.5 months; HR, 0.45). Time to onset of response, overall response rate, and clinical benefit rate were similar in both treatment arms.

Based on these first results, Dr. Lu concluded that “first-line ribociclib plus endocrine therapy offers an efficacious and clinically meaningful treatment option for patients with aggressive HR-positive/HER2-negative advanced breast cancer.”

 

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