Phase IIIb Study of Ribociclib + ET in Early Breast Cancer

Summary

The purpose of this open-label, multicenter, phase IIIb, single-arm study is to characterize the efficacy and safety of the combination of ribociclib and standard adjuvant endocrine therapy (ET) on invasive breast cancer-free survival (iBCFS), in a close to clinical practice patient population with HR-positive (HR+), HER2-negative (HER2-), Anatomic Stage Group III, IIB, and a subset of Stage IIA Early Breast Cancer (EBC).

Eligibility

Study design

Outcome measures

1. Primary outcome

   Invasive Breast Cancer Free Survival (iBCFS) rate at 3 years

   iBCFS is defined as the time from the date of first dose to the date of the first event of invasive ipsilateral breast tumor recurrence, local/regional invasive recurrence, distant recurrence, death (any cause), or contralateral invasive BC. iBCFS will be assessed using STEEP criteria version 2.0 (Standardized Definitions for Efficacy End Points in Adjuvant Breast Cancer Trials), as assessed by Investigator. The iBCFS rate at 3 years will be assessed.

   Time frame At 3 years

2. Secondary outcome

   Incidence and severity of adverse events (AEs) using CTCAE v4.03

   To evaluate Safety of ribociclib + ET

   Time frame Up to approximately 6 years

3. Secondary outcome

   Invasive Disease-Free Survival (iDFS)

   iDFS is defined as the time from the date of first dose of study treatment to the date of the first event of invasive ipsilateral breast tumor recurrence, local/regional invasive recurrence, distant recurrence, death (any cause), contralateral invasive BC, or second primary non-breast invasive cancer (excluding basal and squamous cell carcinomas of the skin). iDFS will be assessed using STEEP 2.0 as assessed by the investigator.

   Time frame Up to approximately 6 years

4. Secondary outcome

   Distant Disease-Free Survival (DDFS)

   Distant Disease-Free Survival (DDFS) is defined as the time from the date of first dose of study treatment to the date of the first event of recurrence at a distant site, death (any cause), or second primary non-breast invasive cancer (excluding in situ/non-invasive cancers and basal and squamous cell carcinomas of the skin). DDFS will be assessed using STEEP 2.0 as assessed by the investigator.

   Time frame Up to approximately 6 years

5. Secondary outcome

   Distant Relapse-Free Survival (DRFS)

   Distant Relapse Free Survival (DRFS) is defined as the time from the date of first dose of study treatment to the date of the first event of recurrence at a distant site or death (any cause). DRFS will be assessed using STEEP 2.0 as assessed by the investigator.

   Time frame Up to approximately 6 years

6. Secondary outcome

   Recurrence-Free Interval (RFI)

   RFI is defined as the time from date of first dose to date of first event of invasive recurrence in the ipsilateral breast or locoregionally, at a distant site, or death from breast cancer. RFI will be assessed using STEEP 2.0 as per investigator assessment.

   Time frame Up to approximately 6 years

7. Secondary outcome

   Relative dose intensity (RDI) of ribociclib

   RDI is defined as the ratio of the dose intensity delivered to the planned dose intensity.

   Time frame Up to 3 years

8. Secondary outcome

   Overall Survival (OS)

   OS is defined as time from the start of study treatment to date of death due to any cause.

   Time frame Up to approximately 6 years

9. Secondary outcome

   Time To Discontinuation (TTD) of ribociclib

   TTD is defined as the time from starting ribociclib to the time to treatment discontinuation due to any cause.

   Time frame Up to 3 years

10. Secondary outcome

    Changes from baseline in Functional Assessment of Cancer Therapy - Breast (FACT-B) score

    The FACT-B is a questionnaire that consists of 37 items with items from FACT-General (FACT-G) questionnaire (27 items) and from the Breast Cancer Subscale (BCS, 10 items). FACT-B consists of five subscales that address different aspects of the participant's quality of life: physical well-being (PWB), social/family well-being (SWB), emotional well-being (EWB), functional well-being (FWB), and BCS.

    Time frame Up to approximately 6 years

11. Secondary outcome

    Changes from baseline in Functional Assessment of Cancer Therapy - Endocrine Symptoms (FACT-ES) score

    The FACT-ES is a questionnaire that consists of 19 items which assesses endocrine complaints and adverse events.

    Time frame Up to approximately 6 years

12. Secondary outcome

    Changes from baseline in Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) score

    The FACIT-F is a 13-item questionnaire designed to assess self-reported fatigue and its impact on daily activities and functions.

    Time frame Up to approximately 6 years

13. Secondary outcome

    Changes from baseline in European Quality of Life-5 Dimensions (EQ-5D-5L) score

    EQ-5D-5L is a standardized participant completed questionnaire that measures health-related quality of life and translates that score into an index value or utility score. EQ-5D-5L consists of two components: a health state profile and an optional visual analogue scale (VAS). EQ-5D-5L health state profile is comprised of 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression.

    Time frame Up to approximately 6 years

14. Secondary outcome

    Changes from baseline in Work Productivity and Activity Impairment Questionnaire (WPAI-GH) score

    WPAI-GH measures the impact of health problems on the participant's productivity, in paid or unpaid activities, in the last 7 days. It is 6-item scale measuring absenteeism, presenteeism, and impairments in unpaid activity.

    Time frame Up to approximately 6 years

Dates

Actual means the event happened. Estimated means the sponsor expects it. The two mean different things.

Locations

118 sites are recruiting

179 further sites are listed in the registry record.

Study documents

No documents are linked in this registry record.

Changes over time

1. September 4, 2026

   Site added

   1 site added (229 total)

   228 → 229

2. August 18, 2026

   Site removed

   1 site removed (228 total)

   229 → 228