Multinational phase 3 trial of ribociclib plus endocrine therapy in early breast cancer

Ribociclib has been shown to have a significant overall survival benefit in patients with HR-positive, HER2-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer (EBC) is unclear. The multinational phase 3 NATALEE trial randomized patients with stage II or III HR-positive, HER2-negative EBC to 3 years of ribociclib plus ≥ 5 years of a nonsteroidal aromatase inhibitor (NSAI; letrozole or anastrozole) or NSAI alone. Interim analysis of the trial found a significant invasive disease-free survival benefit (primary end point) with ribociclib plus an NSAI as compared with an NSAI alone (at 3 years 90.4% versus 87.1%; HR 0.75; p=0.003). Secondary end points distant disease-free survival and recurrence-free survival also favored ribociclib plus an NSAI. There were no new safety signals. The authors conclude that ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III EBC (quick take video summary).