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Study of Abemaciclib and Elacestrant for ER+/HER2- Breast Cancer with Brain Metastasis

This study is testing two drugs, Abemaciclib and Elacestrant, in people with breast cancer that has spread to the brain. Specifically, it's for breast cancer that is estrogen receptor-positive (ER+) and HER-2 negative (HER-2-). The study aims to find the best dose of these drugs when used together and then see how well they shrink tumors. To join, you must be at least 18 years old, male or female, and have signed a consent form. The study will measure how many participants see their tumors shrink over three years. The current status of the study is unclear, but it plans to enroll 73 participants.

Study design
This is an open-label study, meaning you and your doctors will know which treatments you are receiving. It includes a Phase 1b part to find the right dose, followed by a Phase 2 part to evaluate the treatment's effectiveness. The study plans to enroll 73 participants.
What's involved
Not specified in the trial record.
Compensation
Not stated in the trial record.
Follow-up
The study will follow participants for up to 3 years to measure how well the treatment works.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05386108

Study of Abemaciclib and Elacestrant in Participants With Brain Metastasis Due to ER+/HER-2- Breast Cancer

Recruiting
PHASE1Ages 18+InterventionalTreatment
Stemline Therapeutics, Inc.
~73 participants
Updated 2026-08-06 on ClinicalTrials.gov
What's tested:ElacestrantAbemaciclib

At a glance

Recruiting sites
80 of 86 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Phase 1b: RP2D
Measured over Cycle 1 (28 days)
+1 more outcome measured

Conditions

Breast Neoplasms
Brain Neoplasms
Neoplasms by Site
Neoplasms
Breast Diseases
Central Nervous System Neoplasms
Brain Diseases
Central Nervous System Diseases

Explore related trials

Breast CarcinomaMetastatic Malignant Neoplasm in the Brain

Where it's being run

86 sites across 21 states
Italy14
Turkey (Türkiye)11
France9
Germany9
Spain9
South Korea6
United Kingdom5
Greece4

Who to contact

Stemline Trials
[email protected]
1-877-332-7961
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

Female participants may be either postmenopausal or pre/perimenopausal. Postmenopausal status is defined by:
Pre-menopausal / peri-menopausal women and men must be concurrently receiving a luteinizing hormone-releasing hormone (LHRH) agonist starting at least 3-4 weeks before the start of trial therapy and is planning to continue LHRH during the study. 3. Participant must have ER-positive, HER-2 negative tumor status as confirmed by local laboratory testing in the following manner:
Documentation of ER positive tumor with ≥ 1% staining by immunohistochemistry (IHC) as defined in the 2010 or 2020 American Society for Clinical Oncology (ASCO) recommendations for ER testing, with or without progesterone receptor (PGR) positivity
HER-2 negative tumor with an IHC result of 0 or 1+ for cellular membrane protein expression or an in situ hybridization negative result as defined in the 2013 or 2018 ASCO recommendations for HER-2 testing 4. In Phase 2, participants must have at least one active and measurable brain metastasis per RECIST version 1.1.
Any of the following qualifies brain metastases as active:
For lesions, including brain metastases, to qualify as measurable, and possibly be selected as target lesions, per RECIST version 1.1, the longest diameter must be ≥10 millimeters \[mm\] by computed tomography \[CT\] or magnetic resonance imaging \[MRI\]).
In Phase 1b, the presence of brain metastases is allowed but not required for eligibility, in this case, at least 1 measurable lesion outside the brain is required. 5. Participants receiving concomitant corticosteroids must be on a stable or decreasing dose for at least 7 days prior to baseline and not receiving doses higher than 4 mg of dexamethasone per day or equivalent. 6. Participants have experienced no more than one seizure within 4 weeks prior to starting trial therapy. 7. Participants' prior therapy received in the metastatic setting includes:
At least one endocrine therapy
Up to two chemotherapy regimens
Up to two lines of prior cyclin-dependent kinase (CDK) 4/6 inhibitor, not including abemaciclib

Exclusion

Fulvestrant treatment (last injection) \<42 days before first dose of study drug
Any other endocrine therapy \<14 days before first dose of study drug. Note: LHRH agonists should not be counted as endocrine therapy.
Chemotherapy or other anti-cancer therapy \<14 days before first dose of study drug
Any investigational anti-cancer drug therapy within \<28 days or \<5 half lives, whichever is shorter
Bisphosphonates or receptor activator of nuclear factor-κB ligand (RANKL) inhibitors initiated, or dose changed \<1 month prior to first dose of study drug according to institutional guidelines. 11. Radiation therapy (including CNS directed) within 7 days before the first dose of study drug or without a full recovery from radiotherapy acute effects. 12. Uncontrolled significant active infections
Participants with hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection must have undetectable viral load (or detected below the lower limit of quantification) during screening
Participants known to be human immunodeficiency virus positive (HIV+) are allowed as long as they have undetectable viral load (viral suppression) at baseline. 13. Major surgery within 4 weeks of starting trial therapy. 14. Inability to take oral medication, or history of malabsorption syndrome or any other uncontrolled gastrointestinal condition that may significantly alter the absorption of study drugs. 15. Females of childbearing potential who do not agree to use a highly effective non-hormonal method of contraception and to abstain from donating ova within 28 days of the first dose of study treatment through 120 days after the last dose of study treatment. Highly effective non-hormonal method of contraception includes any of the following:

What this trial measures

  • Phase 1b: RP2DCycle 1 (28 days)

    Based on the observed number of dose-limiting toxicities (DLTs) during the first cycle. Dose-limiting toxicity is based on the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. DLTs will be evaluated during the first cycle (28 days) of treatment in up to 3 cohorts during Phase 1b. A DLT will be defined as any of the toxicities listed in the protocol that are not clearly due to breast cancer or extraneous causes.

  • Phase 2: Objective Response Rate (ORR) Per Overall Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST V1.1)3 years

    Defined as the proportion of participants with a best overall response (BOR) of either a confirmed complete response (CR) or partial response (PR) per blinded independent central review (BICR).