NATALEE Trial: Ribociclib Plus NSAI in Node-Negative Breast Cancer Subgroup

By: Joshua D. Madera, MD
Posted: Friday, July 19, 2024

Investigators took a closer look at the NATALEE trial of the CDK4/6 inhibitor ribociclib in combination with a nonsteroidal aromatase inhibitor (NSAI) in patients with hormone receptor (HR)-positive, HER2-negative, early-stage breast cancer. In the subgroup of patients with node-negative disease, who are at increased risk of recurrence, combined ribociclib and NSAI therapy resulted in consistent clinical benefits with a favorable safety profile, according to Denise A. Yardley, MD, of the Sarah Cannon Research Institute, Nashville, and colleagues, during a presentation at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 512).

A total of 5,101 patients with stage II or III HR-positive, HER2-negative, early-stage breast cancer were recruited for the study. All patients were randomly assigned to receive treatment with either ribociclib plus an NSAI (n = 2,549) or an NSAI alone (n = 2,552). NSAI options included letrozole or anastrozole.

Node-negative disease was identified in 11% of patients who received the combination therapy and 13% of patients treated with an NSAI alone. Of this subgroup, about three-quarters of each treatment arm had anatomic stage IIA disease; approximately 10% of both treatment arms had stage III disease.

Patients treated with ribociclib plus an NSAI had significantly improved invasive disease–free survival (hazard ratio [HR] = 0.72), distant recurrence–free survival (HR = 0.58), and distant disease–free survival (HR = 0.70) compared with patients treated with an NSAI alone. Specifically, the 3-year rate of invasive disease–free survival in the node-negative subgroup was 92.3% with ribociclib and 90.6% without it—consistent with the intent-to-treat population. Also, in this node-negative subgroup, the 3-year rates of distant disease–free survival were 94.3% with ribociclib and 91.5% without it. Finally, in those with high-risk node-negative disease, the 3-year rates of distant recurrence–free survival were 96.3% with ribociclib and 92.5% without it. Moreover, 24% of patients who received ribociclib plus an NSAI and 8% of patients who received an NSAI alone required discontinuation of treatment secondary to treatment-related adverse events.

Disclosures: For full disclosures of the study authors, visit coi.asco.org.

2024 ASCO Annual Meeting

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