Final Results of RIGHT Choice: Ribociclib Plus Endocrine Therapy Versus Combination Chemotherapy in Premenopausal Women With Clinically Aggressive Hormone Receptor–Positive/Human Epidermal Growth Factor Receptor 2–Negative Advanced Breast Cancer

Author(s): Yen-Shen Lu, MD, PhD1; Eznal Izwadi Bin Mohd Mahidin, MD2; Hamdy Azim, MD3; Yesim Eralp, MD4; Yoon Sim Yap, MD, PhD5; Seock-Ah Im, MD, PhD6; Julie Rihani7; Erhan Gokmen, MD, PhD8; Ahmed El Bastawisy, MD9; Nuri Karadurmus, MD10; Yueh Ni Lim, MD11; Chun Sen Lim, MD12; Le Thanh Duc, MD13; Wei-Pang Chung, MD14; K. Govind Babu, MD15; Konstantin Penkov, MD16; James Bowles, BMedSci17; Teresa Delgar Alfaro, PharmD, MSc17; Jiwen Wu, PhD18; Melissa Gao, MD, PhD17; Khemaies Slimane, MD17; Nagi S. El Saghir, MD19
Source: https://doi.org/10.1200/JCO.24.00144

Dr. Maen Hussein's Thoughts

Myth busted. In aggressive breast cancer, no need to start chemotherapy now, ET and CKD4/6 inhibitors are better tolerated with significant progression-free survival (PFS) benefit and same response rate.

PURPOSE

A head-to-head comparison of efficacy between a cyclin-dependent kinase 4/6 inhibitor plus endocrine therapy (ET) versus combination chemotherapy (CT) has never been reported in patients with clinically aggressive hormone receptor–positive, human epidermal growth factor receptor 2–negative (HR+/HER2–) advanced breast cancer (ABC).

METHODS

In this open-label, multicenter, randomized phase II trial, pre/perimenopausal women with clinically aggressive HR+/HER2– ABC were randomly assigned 1:1 to first-line ribociclib (600 mg once daily; 3 weeks on, 1 week off) plus letrozole/anastrozole and goserelin or investigator’s choice of combination CT (docetaxel plus capecitabine, paclitaxel plus gemcitabine, or capecitabine plus vinorelbine). The primary end point was progression-free survival (PFS).

RESULTS

Among 222 patients randomly assigned to ribociclib plus ET (n = 112) or combination CT (n = 110), 150 (67.6%) had symptomatic visceral metastases, 41 (18.5%) had rapid disease progression per investigator’s judgment, and 31 (14.0%) had symptomatic nonvisceral disease. Overall, 106 (47.7%) patients had investigator-assessed visceral crisis. The median follow-up time was 37.0 months. At data cutoff, 31.3% (ribociclib arm) and 15.5% (CT arm) of patients had completed study treatment and transitioned to post-trial access. The median PFS was 21.8 months (ribociclib plus ET; [95% CI, 17.4 to 26.7]) and 12.8 months (combination CT; [95% CI, 10.1 to 18.4); hazard ratio, 0.61 [95% CI, 0.43 to 0.87]; P = .003. The overall response rates and the median time to response in the ribociclib versus CT arms, respectively, were 66.1% and 61.8% and 4.9 months and 3.2 months (hazard ratio, 0.76 [95% CI, 0.55 to 1.06]). Lower rates of symptomatic adverse events were observed in the ribociclib versus CT arm.

CONCLUSION

First-line ribociclib plus ET showed a significant PFS benefit, similar response rates, and better tolerability over combination CT in patients with clinically aggressive HR+/HER2– ABC.

Author Affiliations

1National Taiwan University Hospital, Taipei, Taiwan; 2Hospital Kuala Lumpur, Kuala Lumpur, Malaysia; 3School of Medicine, Cairo University, Cairo, Egypt; 4Acıbadem Research Institute of Senology, Acıbadem University, Istanbul, Turkey; 5National Cancer Centre Singapore, Singapore; 6Seoul National University Hospital, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea; 7Independent Patient Advocate, Amman, Jordan; 8Ege University Faculty of Medicine, Izmir, Turkey; 9National Cancer Institute, Cairo University, Giza, Egypt; 10Gülhane Education and Research Hospital, University of Health Sciences, Ankara, Turkey; 11Sarawak General Hospital, Kuching, Sarawak, Malaysia; 12Hospital Sultan Ismail, Johor Bharu, Johor Darul Ta’zim, Malaysia; 13National Cancer Hospital, Hanoi, Vietnam; 14National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; 15HCG Curie Centre of Oncology and Kidwai Memorial Institute of Oncology, Bangalore, India; 16Private Medical Institution Euromedservice, St Petersburg, Russian Federation; 17Novartis Pharma AG, Basel, Switzerland; 18Novartis Pharmaceuticals Corporation, East Hanover, NJ; 19American University of Beirut Medical Center, Beirut, Lebanon

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