NATALEE 5-Year IDFS Data at SABCS 2025

Matthew Kurian, MD St. Elizabeth Healthcare | Jasmin Hundal, MD Cleveland Clinic

January 2, 2026

Copy Link Share
Key Points

  • 5-year follow-up data from NATALEE showed a growing survival benefit with adjuvant ribociclib in hormone receptor-positive breast cancer.

  • Ribociclib and abemaciclib data continue to show the feasibility of adjuvant CDK4/6 inhibitor therapy for early breast cancer.

  • More research is needed to evaluate the combination or sequencing of CDK4/6 inhibitors and oral selective estrogen receptor degraders (SERDs) across lines of therapy.

SABCS 2025 Adjuvant Ribociclib Data Update

At the 2025 San Antonio Breast Cancer Symposium (SABCS 2025), Matthew Kurian, MD, of St. Elizabeth Healthcare, and Jasmin Hundal, MD, MS, MPH, of Cleveland Clinic, spoke about adjuvant CDK4/6 inhibitors in breast cancer in light of the 5-year invasive disease-free survival (IDFS) data from the NATALEE trial on ribociclib. 

Compared with previous presentations, the 5-year data updates from NATALEE at the 2025 European Society for Medical Oncology Congress and at SABCS 2025 showed a growing separation in IDFS benefit with ribociclib plus endocrine therapy versus endocrine therapy alone. 

Overall survival (OS) data are still not mature for NATALEE, and the trial was not powered for OS, so confirming an OS benefit will require additional patient follow-up, said Dr. Kurian. Regardless, the 5-year IDFS data for ribociclib reassured breast medical oncologists that adjuvant CDK4/6 inhibitors are providing a benefit worth the increased toxicity.

For physicians, the choice between ribociclib and abemaciclib depends on each patient. Abemaciclib is associated with more gastrointestinal side effects, particularly diarrhea, while ribociclib is associated with more neutropenia events and, more rarely, QTc prolongation and liver enzyme elevation. Ribociclib also has broader eligibility criteria compared with abemaciclib. 

As physicians continue to implement adjuvant ribociclib and abemaciclib in adjuvant breast cancer, the next question is how data on oral SERDs, like the lidERA trial on giredestrant, may affect the role of CDK4/6 across breast cancer settings.