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
Authors: Lu Yen-Shen , Mahidin Eznal Izwadi Bin Mohd , Azim Hamdy , Eralp Yesim , Yap Yoon Sim , Im Seock-Ah , Rihani Julie , Gokmen Erhan , El Bastawisy Ahmed , Karadurmus Nuri , Lim Yueh Ni , Lim Chun Sen , Duc Le Thanh , Chung Wei-Pang , Babu K. Govind , Penkov Konstantin , Bowles James , Alfaro Teresa Delgar , Wu Jiwen , Gao Melissa , Slimane Khemaies , El Saghir Nagi S. , Alsayed Adher , El Bastawisy Ahmed , Gogia Ajay , Charoentum Chaiyut , Goswami Chanchal , Liu Chien-Ting , Lim Chun Sen , Artamonova Elena , Gokmen Erhan , Namal Esat , Mohd Mahidin Eznal Izwadi , Farhat Fadi , Li Tze Flora Chong , Başaran Gül , Harputluoglu Hakan , Azim Hamdy Abdel , Abdelrazeq Hikmat , ElGhazaly Hesham , Babu K. Govind , Penkov Konstantin , Duc Le Thanh , Tseng Ling-Ming , Osmanova Liudmila , Zhukova Ludmila , Konatum Meher Lakshmi , Nahit Şendur Mehmet Ali , Dai Ming-Shen , Ayoubi Mona , El-Saghir Nagi , Prasongsook Naiyarat , Parinyanitikul Napa , Volkov Nikita , Karadurmus Nuri , Sunpaweravong Patrapim , Siang Ang Peter Cher , Voon Pei Jye , Gaafar Rabab , Motagaly Rasha Abdel , Khanyile Richard , Goksu Sema Sezgin , Chen Shin-Cheh , Gupta Sudeep , Lynette Ngo Su Mien , Choong Swee Hsia , Huang Tan Terence Aik , Demirci Umut , Chung Wei-Pang , Hsieh Wen-Son , Lu Yen-Shen , Eralp Yesim , Yap Yoon Sim , Chang Yuan-Ching , Lim Yueh Ni 
Published: May 2024

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.