JBCRG-S04

Retrospective Real-world Observational Study on Abemaciclib Plus Endocrine Therapy Versus Endocrine Monotherapy as First-Line Treatment in Hormone Receptor-Positive, HER2-Negative Advanced/Metastatic Breast Cancer - JBCRG-S04

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

JPRN

Registry ID

JPRN-jRCT1070250028

Enrollment

750

Registered

2025-06-03

Start date

2025-06-03

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

hormone receptor-positive, HER2-negative advanced metastatic breast cancer (AMBC)

Interventions

None listed

Eligibility

Inclusion criteria

Inclusion criteria: Eligible subjects enrolled in JBCRG-C10 (C10 Cohort) or ABCD Project (ABCD Cohort) Eligibility Criteria C10 Cohort: Subjects enrolled in JBCRG-C10 and meeting the following criteria: 1.ABE was initiated as first-line treatment* for AMBC in combination with an aromatase inhibitor (AI) or fulvestrant (FUL) as ET. *Definition of first-line treatment: The first treatment after being diagnosed with AMBC. 2.No intention of refusal for secondary use of data. ABCD Cohort: Subjects enrolled in the ABCD project and meeting the following criteria: 1.Menopausal status is not considered. 2.Confirmed to be estrogen receptor (ER) positive (1% or more) or progesterone receptor (PgR) positive (1% or more). 3.Confirmed to be HER2 negative (Definition of HER2 negative: IHC 1+ or less, or FISH/DISH negative). 4.ABE was initiated as first-line treatment* for AMBC in combination with AI or FUL as ET (ABE+ET combination group). Alternatively, AI or FUL as ET was initiated as first-line treatment (ET alone group). *Definition of first-line treatment: The first treatment after being diagnosed with AMBC. 5.In the case of the ET monotherapy group, ET was administered as first-line treatment for more than 2 months (in case of the comparative analysis with the C10 cohort). 6.If ABE was used as perioperative treatment, the period from the last administration date to the AMBC diagnosis date is 6 months or more. 7.Treatment was initiated on or after January 1, 2019. 8.No indication of refusal for secondary use of data.

Exclusion criteria

Exclusion criteria: None

Design outcomes

Primary

Measure	Time frame
the Time to Next Treatment (TTNT) from the start of first-line treatment to the start of second-line treatment in the ABE+ET combination group of the C10 Cohort	—

Secondary

Measure	Time frame
Secondary endpoints include Chemotherapy Free Survival (CFS), which is the period until the start of chemotherapy, in the ABE+ET combination group of the C10 Cohort and the ABCD Cohort.	—

Contacts

Public ContactTetsuhiro Yoshinami

Osaka University Hospital

t2hr_y@yahoo.co.jp+81-6-6879-5111

Outcome results