CDK4/6 Inhibitor Use May Expand in HR+ HER2– Breast Cancer

At the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, CancerNetwork® spoke with Daniel G. Stover, MD, who highlighted the invasive disease-free survival (iDFS) benefit associated with ribociclib (Kisqali) in the treatment of patients with hormone receptor (HR)–positive, HER2-negative breast cancer, as noted in the phase 3 NATALEE trial (NCT03701334).

According to Stover, associate professor of medicine and director of Translational Breast Cancer Research at The Ohio State University Comprehensive Cancer Center, results from the NATALEE trial may raise questions about expanding the role of CDK4/6 inhibitors to include the aforementioned patient population.

In the NATALEE trial, the addition of ribociclib to endocrine therapy reduced the risk of invasive disease by 25.2% compared with endocrine therapy alone (Hazard ratio [HR], 0.748; 95% CI, 0.618-0.906; P = .0014). Investigators reported that this iDFS benefit with ribociclib plus endocrine therapy was consistent across key prespecified subgroups based on factors including menopausal status, region, and histological grade. Additionally, ribociclib plus endocrine therapy reduced the risk of distant disease by 26.1% vs endocrine therapy alone (HR, 0.739; 95% CI, 0.603-0.905; P = .0017).

Transcript:

Likely the most practice changing breast cancer [study] from ASCO 2023 is the presentation of the NATALEE results, which showed a significant association of the addition of CDK4/6 inhibitor ribociclib [to endocrine therapy] with [iDFS] among patients with stage II or stage III [HR]-positive, HER2-negative breast cancer.

This is a much broader population of patients than what fits the current FDA approval for abemaciclib [Verzenio], and it raises the question as to whether we're going to substantially expand the proportion of patients who receive adjuvant CDK4/6 inhibitors in stage II or III [HR]-positive breast cancer.

Reference

Slamon DJ, Stroyakovskiy D, Yardley DA, 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. J Clin Oncol. 2023;41(suppl 17):LBA500. doi:10.1200/JCO.2023.41.17_suppl.LBA500