Adjuvant ribociclib improves invasive DFS in early breast cancer

The addition of the CDK4/6 inhibitor ribociclib to adjuvant endocrine therapy improved invasive and distant disease-free survival (DFS) of patients with early-stage HR⁺/HER2^- breast cancer, as shown by the primary results of the phase 3 NATALEE trial.

The current standard-of-care for patients with early-stage HR⁺/HER2^- breast cancer is surgery with or without radiotherapy followed by 5 or 10 years of adjuvant endocrine therapy. However, up to one-third of patients with stage II and more than half of patients with stage III HR⁺/HER2^- early breast cancer will experience disease recurrence [1]. In patients with advanced HR⁺/HER2^- breast cancer, the addition of a CDK4/6 inhibitor to endocrine therapy increases disease-free and overall survival, while maintaining quality of life [2].

The phase 3 NATALEE trial (NCT03701334) evaluated the addition of the CDK4/6 inhibitor ribociclib to endocrine therapy in patients with early-stage HR⁺/HER2^- breast cancer. Prof. Dennis Slamon (David Geffen School of Medicine, CA, USA) presented primary results [3].

NATALEE randomised 5,101 participants with early-stage HR⁺/HER2^- breast cancer 1:1 to adjuvant treatment with ribociclib (400 mg/day for 3 years) plus endocrine therapy (for at least 5 years) or treatment with endocrine therapy alone. As of the data cut-off, the median follow-up was 34 months.

Adding ribociclib to adjuvant endocrine therapy significantly improved the primary endpoint: invasive disease-free survival (iDFS) rate at 3 years was 90.4% versus 87.1% (HR 0.748; P=0.0014). The absolute iDFS benefit at 3 years follow-up was 3.3%. The risk of invasive disease was reduced by 25.2%. The iDFS benefit was consistent across all prespecified subgroups. In addition, the 3-year distant DFS rate was significantly improved in patients treated with ribociclib: 90.8% versus 88.6% (HR 0.739; P=0.0017). The risk of distant disease (metastasis) was reduced by 26.1%. The overall survival data are not yet mature.

Based on these results, Prof. Slamon concluded that the “NATALEE results support ribociclib plus endocrine therapy as a new treatment of choice in a broad population of patients with HR⁺/HER2^- early breast cancer.”

1. Pan H, et al. N Engl J Med 2017;377:1836–1846.
2. Harbeck N, et al. Ther Adv Med Oncol. 2020;12:1758835920943065.
3. Slamon DJ, et al. Ribociclib and endocrine therapy as adjuvant treatment in patients with HR+/HER2- early breast cancer: primary results from the phase III NATALEE trial. Abstract LBA500, ASCO Annual Meeting 2023, 2–6 June, Chicago, USA.

 

Copyright ©2023 Medicom Medical Publishers



Posted on 2 August, 20232 August, 2023