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

NCT05305924 | Recruiting Phase 2 DMC FDA Drug

• 1 other identifier: PRO00028925
• Study Type: interventional
• Target: 28
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

ER-Positive Breast Cancer; HER2-negative Breast Cancer

Keywords

Fulvestrant; Abemaciclib; CDK4/6 Inhibitor; Aromatase Inhibitor

Outcome Measures

Primary Outcomes (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.

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

Secondary Outcomes (5)

• Estimation of the CBR of fulvestrant plus abemaciclib with a 1-month run-in of fulvestrant

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

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

  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.

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

  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.

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

  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.

• 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, as assessed by the RECIST 1.1 through study completion, an average of 1 year.

Study Arms (1)

Fulvestrant plus Abemaciclib Arm with Fulvestrant Run-In

EXPERIMENTAL

A 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

Drug: Fulvestrant Run-In

Interventions

Fulvestrant Run-In DRUG

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.

Also known as: Abemaciclib, Fulvestrant

Fulvestrant plus Abemaciclib Arm with Fulvestrant Run-In

Eligibility Criteria

• Age: 18 Years+
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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
• 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.

You may not qualify if:

• 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.
• 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.

Sponsors & Collaborators

• The Methodist Hospital Research Institute: lead
• Eli Lilly and Company: collaborator

Study Sites (1)

Houston Methodist Cancer Center

Houston, Texas, 77030, United States

RECRUITING

MeSH Terms

Interventions

abemaciclib; Fulvestrant

Intervention Hierarchy (Ancestors)

Estradiol; Estrenes; Estranes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Estradiol Congeners; Gonadal Steroid Hormones; Gonadal Hormones; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists

Study Officials

• Polly Niravath, MD

  The Methodist Hospital Research Institute

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Polly Niravath, MD

CONTACT

713-441-0629; ccresearch@houstonmethodist.org

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor of Medicine in Oncology, Academic Institute

Study Record Dates

• First Submitted: March 11, 2022
• First Posted: March 31, 2022
• Study Start: February 25, 2021
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2027
• Last Updated: January 28, 2026

Record last verified: 2026-01

Locations

US (1)