20 Impact of Ribociclib Dose Reduction on Efficacy in Patients With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast

Publication
Article
Miami Breast Cancer Conference® Abstracts Supplement42nd Annual Miami Breast Cancer Conference® - Abstracts
Volume 39
Issue 4
Pages: 11-12

20 Impact of Ribociclib Dose Reduction on Efficacy in Patients With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast

20 Impact of Ribociclib Dose Reduction on Efficacy in Patients With Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Early Breast

Background

The NATALEE trial showed statistically significant and clinically meaningful invasive disease-free survival (iDFS) with ribociclib plus a nonsteroidal aromatase inhibitor (NSAI) vs NSAI in patients with stage II/III hormone receptor–positive (HR+)/HER2-negative (HER2–) early breast cancer (EBC; HR, 0.715; 95% CI, 0.609-0.840; 4-year absolute benefit, 4.9%; median follow-up, 44.2 months). We present an exploratory analysis of efficacy in patients with and without dose reduction.

Materials and Methods

Men and pre- and postmenopausal women with HR+/HER2− EBC were randomized 1:1 to receive ribociclib (400 mg/day; 3 wks on/1 week off for 36 months) plus NSAI or NSAI alone. Key inclusion criteria were stage II/III disease (AJCC 8th edition); patients with node-negative stage IIA disease (T2N0) were required to have additional high-risk criteria (grade 2 with Ki-67 ≥ 20% or high genomic risk; or grade 3). Only 1 ribociclib dose reduction (400 mg/day to 200 mg/day) was allowed for the management of adverse effects (AEs). Relative dose intensity (RDI; actual cumulative dose per duration of exposure [adjusted for 3-weeks-on/1-week-off schedule] divided by planned dose intensity of 400 mg/day) was analyzed by grouping patients into low, medium, or high RDI tertiles and summarized using Kaplan Meier methods. A stratified Cox proportional hazards model was used to compare iDFS rates with ribociclib across tertiles. The data cutoff date was Apr 29, 2024 (median follow-up, 44.2 mo).

Results

Among 2526 patients who received treatment in the ribociclib plus NSAI arm, 27.2% had a ribociclib dose reduction, and 72.8% did not. The median time for the dose reduction was 3.3 months. The most common reason for dose reduction was an AE (23.0%); the most common AEs leading to dose reduction included neutropenia (14.0%), alanine aminotransferase increased (1.9%), and fatigue (1.0%). Baseline characteristics were balanced. Duration of ribociclib exposure was similar among patients with and without a dose reduction (median, 35.7 months in both groups). RDI did not impact iDFS rates. Patients with low, medium, and high RDI had similar iDFS rates.

Conclusion

This post hoc exploratory analysis of NATALEE demonstrated that iDFS benefit was maintained among patients who had a dose reduction of RIB and were not impacted by ribociclib RDI. These data suggest it may be possible to implement a dose reduction of ribociclib to 200 mg/day when needed to manage AEs without compromising efficacy for patients with HR+/HER2− EBC.

Articles in this issue

2 Preventive Care and Screening Adherence Among Women Surviving Breast Cancer
2 Preventive Care and Screening Adherence Among Women Surviving Breast Cancer
3 Intraoperative Radiotherapy: Alive and Well in the Bronx
3 Intraoperative Radiotherapy: Alive and Well in the Bronx
4 Evaluating AI-Driven Responses in Breast Reconstruction: A Comparative Study of Response Formats
4 Evaluating AI-Driven Responses in Breast Reconstruction: A Comparative Study of Response Formats
5 Correlation Between Visual Impairment and Breast Cancer: A Cross-Sectional Study Based on the National Health Interview Surveys
5 Correlation Between Visual Impairment and Breast Cancer: A Cross-Sectional Study Based on the National Health Interview Surveys
6 Peer Support Programming Among Women At-Risk for Surviving Breast Cancer: Facilitators and Barriers to Community-Based Patient Navigation and the Role of Quality of Life
6 Peer Support Programming Among Women At-Risk for Surviving Breast Cancer: Facilitators and Barriers to Community-Based Patient Navigation and the Role of Quality of Life
7 Metaplastic Breast Cancer: A Retrospective Chart Review of Clinical Features
7 Metaplastic Breast Cancer: A Retrospective Chart Review of Clinical Features
8 A Case Series Exploring Characteristics and Outcomes of Metachronous Primary Breast and Lung Cancer in a Diverse Cohort
8 A Case Series Exploring Characteristics and Outcomes of Metachronous Primary Breast and Lung Cancer in a Diverse Cohort
9 Body Mass Index, Cancer Risk Behaviors, and Readiness for Dietary Change Among Women Surviving With Breast Cancer
9 Body Mass Index, Cancer Risk Behaviors, and Readiness for Dietary Change Among Women Surviving With Breast Cancer
10 AI as a Bridge: Can ChatGPT Help Patients Understand Their Breast Radiology Reports?
10 AI as a Bridge: Can ChatGPT Help Patients Understand Their Breast Radiology Reports?
12 Gut Microbiome Composition and Pathological Complete Response After Chemotherapy in Breast Cancer: Insights From a Pilot Study
12 Gut Microbiome Composition and Pathological Complete Response After Chemotherapy in Breast Cancer: Insights From a Pilot Study
13 Preliminary Analysis of Change During Treatment of Financial Toxicity and Quality of Life in Breast Cancer Patients
13 Preliminary Analysis of Change During Treatment of Financial Toxicity and Quality of Life in Breast Cancer Patients
15 Utilizing Circulating Tumor Cells to Guide HER2-Directed Therapy in IHC/FISH-Negative HER2+ Metastatic Breast Cancer
15 Utilizing Circulating Tumor Cells to Guide HER2-Directed Therapy in IHC/FISH-Negative HER2+ Metastatic Breast Cancer
16 A Miami Hospital’s Infrastructure to Help Decrease Late-Stage Breast Cancer Diagnosis and Improve Health Equity
16 A Miami Hospital’s Infrastructure to Help Decrease Late-Stage Breast Cancer Diagnosis and Improve Health Equity
17 Salmonella and the Breast: A Literature Review of Salmonella-Induced Breast Abscesses
17 Salmonella and the Breast: A Literature Review of Salmonella-Induced Breast Abscesses
18 Tolerability of First-Line Treatment With Ribociclib for Metastatic Breast Cancer Using 2 Large US Data Sources
18 Tolerability of First-Line Treatment With Ribociclib for Metastatic Breast Cancer Using 2 Large US Data Sources
Recent Videos
Leading experts in the breast cancer field highlight the use of CDK4/6 inhibitors, antibody-drug conjugates, and other treatment modalities.
Patients with node-negative disease who are older and have comorbidities may not be suitable to receive CDK4/6 inhibitors.
An observed carryover effect with CDK4/6 inhibitors may reduce the risk of recurrence years after a patient stops treatment.
Breast oncologist Jade E. Jones, MD, says she tries to send patients with BRCA-mutant HR-positive TNBC to clinical trials that use PARP inhibitors.
Related Content