AzTrials
AzTrials

ER-Positive Breast CancerPhase 2NCT05305924

Fulvestrant+Abemaciclib With Run-In of Fulvestrant in Er-Positive, Her2-Negative Metastatic Breast Cancer

A Phase 2 study testing Fulvestrant Run-In in people with ER-Positive Breast Cancer and HER2-negative Breast Cancer, run by The Methodist Hospital Research Institute at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

The study will investigate if CDK4/6 inhibitor holiday will reset the cell cycle process to respond to the combination of fulvestrant and abemaciclib, and this approach may represent an effective therapeutic strategy to manage such patients. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Fulvestrant Run-In
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
28 participants
Where
1 siteUnited States
Study dates
25 Feb 2021to 1 Dec 2027
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Male or Female >18 years of age on the day of informed consent signing.
  • Progression on a CDK4/6 inhibitor in combination with an AI immediately prior to the enrollment on this study
  • Histologically confirmed ER-positive, HER2-negative metastatic breast cancer. ER-positive is defined as ≥1% immunohistochemical (IHC) staining of any intensity. HER2 test result is negative if a single test (or both tests) performed show:
  • IHC 1+ or 0
  • In situ hybridization negative based on:
  • Single-probe average HER2 copy number <4.0 signals/cell
Show all 29Show fewer
  • Dual-probe HER2/CEP17 ratio <2.0 with an average HER2 copy number <4.0 signals/cell.
  • Measurable disease according to the RECIST 1.1 or bone-only disease.
  • Postmenopausal status or receiving ovarian ablation with a gonadotropin-releasing hormone (GnRH) agonist. Postmenopausal status is defined by any one of the following criteria:
  • Prior bilateral oophorectomy
  • Age ≥55 years
  • Age <55 years and amenorrheic for at least 12 months (spontaneous cessation of menses for 12 consecutive months or more in the absence of chemotherapy, tamoxifen, toremifene, or ovarian suppression) and follicle-stimulating hormone and estradiol levels in the postmenopausal range without an alternative cause If the patient does not meet criteria for postmenopausal status but is receiving ovarian ablation therapy with a GnRH agonist, the patient is eligible for this trial, provided that the GnRH agonist is started at least 2 weeks prior to the first dose of trial treatment.
  • Eastern Cooperative Oncology Group performance status of 0 or 1.
  • Life expectancy ≥6 months.
  • Patients who received chemotherapy must have recovered (Common Terminology Criteria for Adverse Events [CTCAE] Grade ≤1) from the acute effects of chemotherapy except for residual alopecia or Grade 2 peripheral neuropathy prior to randomization. A washout period of at least 21 days is required between last chemotherapy dose and randomization (provided the patient did not receive radiotherapy). Patients who received radiotherapy must have completed and fully recovered from the acute effects of radiotherapy. A washout period of at least 21 days is required between end of radiotherapy and randomization.
  • Adequate organ function:
  • Absolute neutrophil count ≥1500/µL (without granulocyte colony stimulating factor support within 2 weeks of laboratory test used to determine eligibility)
  • Platelets ≥100,000/µL (without transfusion within 2 weeks of laboratory test used to determine eligibility)
  • Hemoglobin ≥9 g/dL (without blood transfusion)
  • White blood cell count >2,500/µL and <15,000/µL
  • Lymphocyte count ≥500/µL
  • Serum bilirubin ≤1.5x upper limit of normal (ULN; patients with known Gilbert's disease who have serum bilirubin level ≤3 x ULN may be enrolled)
  • Serum transaminases (aspartate transaminase [AST] or alanine transaminase [ALT]) activity ≤3.0 x ULN with normal alkaline phosphatase ([ALP]; patients with liver metastases ≤5 x ULN) OR AST and ALT ≤1.5 x ULN with ALP >2.5 x ULN
  • International normalized ratio and activated partial thromboplastin time ≤1.5 x ULN
  • Serum creatinine at or below the institutional normal value.
  • Able to swallow oral medication.
  • Patients who are made postmenopausal through use of GNRH agonists must be willing to use an adequate method of contraception for the course of the trial through 1 year after the last dose of trial treatment.
  • Patients who are made postmenopausal through use of GNRH agonists should have a negative serum pregnancy (β-human chorionic gonadotropin) within 7 days prior to trial treatment administration.
  • Willing and able to provide written informed consent/assent for the trial.

Who cannot join

  • Currently participating and receiving study therapy or has participated in a study of an investigational agent and received study therapy or used an investigational device within 3 weeks of trial treatment administration.
  • Prior chemotherapy, targeted small molecule therapy, or radiation therapy within 2 weeks prior to trial treatment administration or who has not recovered (i.e., ≤ Grade 1 or at baseline) from AEs due to a previously administered agent. Note: If the patient received major surgery, she must have recovered adequately from the toxicity and/or complications from the intervention prior to starting the trial treatment.
  • The patient has had major surgery within 14 days prior to starting the study.
  • Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin or squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer.
  • The patient has serious and/or uncontrolled preexisting medical condition(s) that, in the judgment of the investigator, would preclude participation in this study (for example, interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, severe renal impairment [e.g. estimated creatinine clearance <30ml/min], history of major surgical resection involving the stomach or small bowel, or preexisting Crohn's disease or ulcerative colitis or a preexisting chronic condition resulting in baseline Grade 2 or higher diarrhea).
  • History or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the patient's participation for the full duration of the trial, or is not in the best interest of the patient to participate, in the opinion of the treating investigator.
Show all 21Show fewer
  • Known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
  • Concurrent use of strong cytochrome P450 (CYP)3A inhibitors or inducers.
  • Hypersensitivity to fulvestrant, abemaciclib, or any of their excipients.
  • Manifestations of malabsorption due to prior gastrointestinal surgery, gastrointestinal surgery disease, or an unknown reason.
  • Has a bleeding disorder or currently taking anticoagulants.
  • Has active hepatitis B (detectable hepatitis B surface antigen) or active hepatitis C infection (detectable hepatitis C RNA).
  • Has active systemic bacterial infection (requiring intravenous [IV] antibiotics at time of initiating study treatment), fungal infection, or detectable viral infection (such as known human immunodeficiency virus positivity or with known active hepatitis B or C [for example, hepatitis B surface antigen positive]. Screening is not required for enrollment.
  • Has a personal history of any of the following conditions: syncope of cardiovascular etiology, ventricular arrhythmia of pathological origin (including, but not limited to, ventricular tachycardia and ventricular fibrillation), or sudden cardiac arrest.
  • Documented brain metastases that are untreated, symptomatic, or require therapy to control symptoms. Patients with previously diagnosed brain metastases are eligible if they have completed treatment at least one month prior to trial treatment administration, are neurologically stable, and have recovered from effects of radiotherapy or surgery.
  • Any corticosteroid use for brain metastases must have been discontinued without the subsequent appearance of symptoms for ≥2 weeks before trial treatment administration.
  • Treatment for brain metastases may have included whole brain radiotherapy, radiosurgery, or a combination as was deemed appropriate by the treating physician.
  • Patients who meet the above criteria and are clinically stable on anticonvulsant medication are eligible only if their anticonvulsant does not alter hepatic CYP activity in a way that might interfere with the metabolism of abemaciclib.
  • Have received any live vaccination within 28 days of trial treatment administration.
  • History within the last 12 months of any of the following conditions: syncope of cardiovascular etiology, ventricular tachycardia, ventricular fibrillation, or sudden cardiac arrest.
  • Pregnant or breastfeeding.

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

United States1 site, 1 recruiting
  • Houston Methodist Cancer Center

    Houston, Texas, 77030

    Polly Niravath, MD, 713-441-0629, ccresearch@houstonmethodist.org

    Recruiting

Other trials in United States

About this study

Official title: Phase II Trial Of Fulvestrant Plus Abemaciclib In Er-Positive, Her2-Negative Metastatic Breast Cancer Immediately After Failure Of A Cdk4/6 Inhibitor

The study will investigate if CDK4/6 inhibitor holiday will reset the cell cycle process to respond to the combination of fulvestrant and abemaciclib, and this approach may represent an effective therapeutic strategy to manage such patients.

Read the detailed description

Endocrine therapy, including aromatase inhibitor therapy, is the primary treatment for ER-positive metastatic disease. Despite the effectiveness of this treatment, not all patients respond to it and many patients who are initially responsive to the drug, eventually develop resistance to it. The management of patients with ER-positive, HER2-negative metastatic breast cancer who experience disease progression after standard treatment (CDK4/6 inhibitor plus an aromatase inhibitor) is a significant challenge and identification of new therapeutic strategies for this population of patients remains an unmet clinical need.

The aim of this research study is to determine if a month delay in the administration of the drug abemaciclib will be more effective than the drugs fulvestrant plus abemaciclib given together from the beginning for the treatment of ER-positive, HER2-negative metastatic breast cancer that has progressed on previous treatment. The study will investigate if a one month drug holiday from the CDK4/6 inhibitor drug, abemaciclib, will restore the body's sensitivity to the drug and make the subsequent treatment of abemaciclib plus fulvestrant more effective.

This is a single arm study where patients will receive fulvestrant for 1 month, followed by abemaciclib and fulvestrant every 28 days.

The treatment will be administered until disease progression or unacceptable toxicity.

Being tested
Fulvestrant Run-In
Keywords
Fulvestrant, Abemaciclib, CDK4/6 Inhibitor, Aromatase Inhibitor

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Fulvestrant Run-InDrug

    Also called Abemaciclib, Fulvestrant

    The study is evaluating if a drug holiday (post CDK inhibitors progression) will reset the cell cycle machinery to be responsive to Abemaciclib and Fulvestrant.

Study groups in NCT05305924
Study groupRoleWhat they receive
Fulvestrant plus Abemaciclib Arm with Fulvestrant Run-InExperimentalA 1-month (28 days) run-in of fulvestrant will precede fulvestrant plus abemaciclib treatment. Fulvestrant at a dose of 500 mg will be administered intramuscularly (IM) into the buttocks slowly (1-2 minutes per injection) as two 5-mL injections, one in each buttock, on Days 1 and 15 of the run-in period. After the fulvestrant run-in, fulvestrant plus abemaciclib will be administered in 28-day cycles until disease progression or unacceptable toxicity. Fulvestrant (500 mg IM) will be administered on Day 1 of each 28-day cycle. Abemaciclib at a dose of 150 mg will be given p.o. BID on Days 1-28 of each cycle
Receives: Drug: Fulvestrant Run-In

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Time to treatment failure (TTF) for fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant

    Time to treatment failure (TTF) for fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI, as assessed by the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1.

    Measured: TTF will be defined as time from start of therapy to discontinuation for any cause.

Secondary outcomes (5)
  1. Estimation of the CBR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant

    Estimation of the CBR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI, as assessed by the RECIST 1.1.

    Measured: CBR will be defined as the percentage of patients with CR, PR, or stable disease (SD) according to the RECIST 1.1.

  2. PFS rate between fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant.

    PFS rate between fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI.

    Measured: PFS will be defined as the date of the first dose of trial treatment to the date of progression or death due to any cause, whichever occurs first, assessed up to 12 months after the last subject is added.

  3. Toxicity/safety between fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant.

    Toxicity/safety between fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI, as assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) v4.03.

    Measured: Toxicity will be defined as any treatment-related death or any ≥ Grade 3 AE excluding alopecia and constitutional symptoms as assessed by the NCI CTCAE v4.03 through study completion, an average of 1 year.

  4. Quality of life assessment after fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant.

    Quality of life assessment after fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI, as assessed by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-C30 (EORTC QLQ-C30).

    Measured: Patient-reported quality of life after fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant, as assessed by the EORTC QLQ-C30 through study completion, an average of 1 year.

  5. ORR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant.

    ORR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant in patients with ER-positive, HER2-negative metastatic breast cancer that has progressed on a CDK4/6 inhibitor in combination with an AI, as assessed by the RECIST 1.1

    Measured: ORR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant, as assessed by the RECIST 1.1 through study completion, an average of 1 year.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted31 Mar 2022
  2. Study start25 Feb 2021
  3. Primary completion1 Dec 2026 (estimated)
  4. Study completion1 Dec 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
28 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05305924
Sponsor's protocol ID
PRO00028925
Status last verified
Jan 2026
First submitted
11 Mar 2022
Last updated
28 Jan 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Fulvestrant Run-In in people with ER-Positive Breast Cancer and HER2-negative Breast Cancer, run by The Methodist Hospital Research Institute at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 29 inclusion and 21 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 28 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Polly Niravath, MD (713-441-0629, ccresearch@houstonmethodist.org), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Time to treatment failure (TTF) for fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant (time frame: TTF will be defined as time from start of therapy to discontinuation for any cause.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Jan 2026.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in