Endocrine Therapy / Brain Metastases / HR+ Metastatic Breast Cancer · Phase 1/2 Trial

SR & Abemaciclib With/wo Imlunestrant in the Management of HR+/HER2- Breast CA Brain Metastases

ClinicalTrials.gov · September 11, 2026

Preliminary Why this matters to you Expert discussion

Early or partial results. Treat as a signal, not a conclusion.

AI Summary

This is a registry record for a planned Phase 1/2 single-arm study evaluating stereotactic radiosurgery combined with abemaciclib and endocrine therapy in patients with HR+/HER2- metastatic breast cancer brain metastases. No results are posted; the study is still recruiting and remains in early stage.

What was studied

Phase 1/2, Interventional, Non Randomized, Sequential, Open label, Treatment purpose. Brain Metastases, HR+ Metastatic Breast Cancer; age from 18 Years. Intervention: Phase 1: Radiation Therapy and Abemaciclib; Phase 2: Radiation Therapy and Abemaciclib. n = 31. 2 sites: United States.

Key findings

Safety

Safety was not reported in the material analysed. Check the source before drawing any conclusion about harm.

Who this may help

This trial addresses an unmet need in brain metastases from HR+ breast cancer, but clinicians should await completion and results before interpreting efficacy or safety. The single-arm design precludes comparison to standard of care.

Plain-language summary

This is a Phase 1/2 single-arm trial still recruiting with no posted results; early-phase design and lack of comparative data limit evidential strength.

Study design

As stated by the source record.

MethodsPrimary outcome measure: Intracranial Progression Free Survival (PFS) (assessed at Up to 12 months)

DesignPhase 1/2, Interventional, Non Randomized, Sequential, Open label, Treatment purpose

PopulationBrain Metastases, HR+ Metastatic Breast Cancer; age from 18 Years

Sample size31

InterventionPhase 1: Radiation Therapy and Abemaciclib; Phase 2: Radiation Therapy and Abemaciclib

Setting2 sites: United States

Reported figures

Quoted from the source exactly as published.

Planned enrollment31

Primary outcome measureIntracranial Progression Free Survival (PFS), up to 12 months

Study phasePhase 1, Phase 2

Clinical bottom line

Caveats

This is a registry record only; no results are posted or analysed.
Single-arm design with no control or comparator group limits ability to draw causal conclusions.
Small estimated sample size (31 participants) limits statistical power for definitive inferences.
Study is still recruiting; conduct, completion status, and adherence to protocol are unknown from this record.

Evidence assessment

Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.

Study design

limited

Single-arm Phase 1/2 design without control or comparator group.

Directness

moderate

Addresses HR+/HER2- brain metastases, relevant clinical population and setting.

Consistency

insufficient

No results posted; cannot assess consistency with prior or concurrent evidence.

Risk of bias

insufficient

Registry record does not describe blinding, allocation, or conduct details.

Sample adequacy

limited

Estimated 31 participants; small sample for phase 1/2, underpowered for definitive outcome.

What is missing. This record has no key findings. That is a gap in the analysis, not a judgement about the study.

Source abstract

Registry record from ClinicalTrials.gov (NCT04923542). This is a study registration, not published results. Lead sponsor: H. Lee Moffitt Cancer Center and Research Institute. Recruitment status: RECRUITING. Phase: PHASE1, PHASE2. Study type: INTERVENTIONAL. Enrollment: 31 participants (ESTIMATED). Conditions: Brain Metastases, HR+ Metastatic Breast Cancer. Interventions: RADIATION: Stereotactic Radiosurgery (SRS); DRUG: Abemaciclib; DRUG: Endocrine therapy. Primary outcome measures: Intracranial Progression Free Survival (PFS) , Up to 12 months. Brief summary: This is a single arm study of abemaciclib and endocrine therapy with stereotactic radiosurgery (SRS) among patients with hormone receptor (HR)+/HER2- metastatic breast cancer brain metastases.

Follow from this

Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.

Endocrine TherapyBrain MetastasesHR+ Metastatic Breast CancerStereotactic Radiosurgery (SRS)AbemaciclibH. Lee Moffitt Cancer Center and Research InstituteNCT04923542