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Endometrial Endometrioid AdenocarcinomaEarly Phase 1NCT04049227

Abemaciclib and Letrozole in Treating Patients With Endometrial Cancer

A Early Phase 1 study testing Abemaciclib, Letrozole and Therapeutic Conventional Surgery in people with Endometrial Endometrioid Adenocarcinoma, run by Northwestern University at 2 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This early phase I trial studies how well abemaciclib and letrozole work in treating patients with endometrial cancer and determines whether there are changes in patients' cancer cell biomarkers (a genetic feature or specific protein) for cell growth before and after treatment. Read more about this study

Who is it for?
Ages 18 years and older, women only
Conditions the study is for
Endometrial Endometrioid Adenocarcinoma
What is being tested?
Abemaciclib, Letrozole and Therapeutic Conventional Surgery
Type of treatment
Surgery or procedure
Could I receive a placebo?
No, everyone receives an active treatment
How many people
27 participants
Where
2 sitesUnited States
Study dates
12 Aug 2019to 15 May 2023
Phase
Early Phase 1
Are there results?
None posted in the registry

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
  • Women only
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Patients must have a new histologically confirmed diagnosis of endometrioid adenocarcinoma of the endometrium who are candidates for hysterectomy.
  • Note: Patients with recurrent disease are not eligible.
  • Patients must be willing to provide archival tumor biopsy slides from the specimen (e.g. endometrial biopsy or dilation and curettage) which diagnosed them with endometrial cancer.
  • (Please note: Given the amount of tissue obtained from these specimens is often much more than a core needle biopsy, we do not anticipate difficulties with insufficient tissue.)
  • Patients should be treatment naive. They should not have received any endometrial cancer directed therapy including medroxyprogesterone acetate, aromatase inhibitors, other hormonal treatments or radiation therapy for treatment of endometrial cancer.
  • Note: Patients can have used oral contraceptives or hormonal replacement therapy provided these were discontinued 28 days prior to trial enrollment.
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  • Eastern Cooperative Oncology Group (ECOG) performance status =< 2 within 28 days prior to registration for protocol therapy.
  • Patients must have adequate organ function for all of the following criteria within 28 days of registration.
  • Absolute neutrophil count (ANC) >= 1.5 x 10^9 /L (within 28 days of registration).
  • Platelets >= 100 x 10^9 /L (within 28 days of registration).
  • Hemoglobin >= 8 g/dL (within 28 days of registration).
  • Patients may receive erythrocyte transfusions to achieve this hemoglobin level at the discretion of the investigator. Initial treatment must not begin earlier than the day after the erythrocyte transfusion.
  • Total bilirubin =< 1.5 x upper limit of normal (ULN) (within 28 days of registration).
  • Patients with Gilbert?s syndrome with a total bilirubin =< 2.0 times ULN and direct bilirubin within normal limits are permitted.
  • Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) =< 3 x ULN (within 28 days of registration).
  • Serum creatinine =< 1.5 x ULN (within 28 days of registration).
  • Patients with a history of surgical sterilization are eligible for this study. OR
  • Patients must have post-menopausal status due to menopause (surgical or natural). Patients must meet at least one of the following criteria:
  • Bilateral oophorectomy
  • Age >= 55 years
  • Age =< 55 years and amenorrhea (absence of menstruation) for > 12 months OR
  • Patients who are not post-menopausal or previously sterilized.
  • i.e. a female of childbearing potential (patients who are not post-menopausal), must have a negative serum pregnancy test within 7 days of the first dose of study treatment (abemaciclib and/or letrozole). Patient must agree to use adequate birth control (condoms with spermicidal agent or abstinence) while on the study and for 3 weeks after completion of treatment.
  • Patients should be able to swallow oral medications.
  • Patients must have the ability to understand and the willingness to sign a written informed consent prior to registration on study.
  • Patients must be willing and able to have a window of >= 15 days prior to their scheduled hysterectomy surgery after registration.

Who cannot join

  • Patients who have had chemotherapy, hormonal therapy or radiotherapy directed at the treatment of endometrial cancer prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks prior to registration are not eligible.
  • Patients may not be receiving any other investigational agents. A wash out period of 4 weeks before registration is required for eligibility.
  • Patients who have a history of allergic reactions attributed to compounds of similar chemical or biologic composition to abemaciclib or letrozole or any of its excipients are not eligible.
  • Patients receiving CYP3A inducers or strong CYP3A inhibitors will not be eligible for this study. A wash-out period of minimum 5 half-lives or 7 days, whichever is shorter, before registration is required for the patient to become eligible.
  • Patients who have a known 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 are not eligible.
  • Patients who have known active bacterial infection (requiring intravenous [IV] antibiotics at time of initiating study treatment), fungal infection, or detectable viral infection (such as known human immunodeficiency virus [HIV] positivity or with known active hepatitis B or C (for example, hepatitis B surface antigen positive). Screening is not required for enrollment.
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  • Note: patients with uncomplicated urinary tract infection or uncomplicated cystitis are eligible.
  • Patients who have an uncontrolled intercurrent illness including, but not limited to any of the following, are not eligible:
  • Hypertension that is not controlled on medication
  • Baseline grade 2 or higher diarrhea.
  • Ongoing or active infection requiring systemic treatment.
  • Symptomatic congestive heart failure.
  • Unstable angina pectoris.
  • Psychiatric illness that would limit compliance with study requirements.
  • Social situations that would limit compliance with study requirements.
  • Serious preexisting medical condition(s) that would preclude participation in this study (for example, interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, 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).
  • Any other illness or condition that the treating investigator feels would interfere with study compliance or would compromise the patient?s safety or study endpoints.
  • Female patients who are pregnant or nursing are not eligible.
  • Patients who are unable to retain oral medication, and patients who have gastrointestinal disorders or abnormalities that would interfere with absorption of the study drugs are not eligible.

Trial locations and contacts

2 sites in 1 country.

United States2 sites

  • Northwestern University

    Chicago, Illinois, 60611

  • University of Chicago Comprehensive Cancer Center

    Chicago, Illinois, 60637

Other trials in United States

About this study

Official title: A Pilot, Multicenter, Single Arm, Open Label, Surgical Window of Opportunity Study of Abemaciclib and Letrozole for Endometrioid Adenocarcinoma of the Endometrium

This early phase I trial studies how well abemaciclib and letrozole work in treating patients with endometrial cancer and determines whether there are changes in patients' cancer cell biomarkers (a genetic feature or specific protein) for cell growth before and after treatment. Antihormone therapy with aromatase inhibitors, such as letrozole, may lessen the amount of estrogen made by the body. Abemaciclib blocks the activities of a class of proteins called cyclin-dependent kinase, which are involved in cell duplication. Giving letrozole and abemaciclib together may slow down cancer cell growth in patients with endometrial cancer.

Read the detailed description

PRIMARY OBJECTIVES:

  1. To determine whether there are changes in Ki-67 expression from the pretreatment specimen (e.g. biopsy or dilation and curettage [D\&C]) to the post-treatment hysterectomy specimen following treatment with letrozole and abemaciclib.

SECONDARY OBJECTIVES:

  1. To determine the proportion of tumors with complete cell cycle arrest (CCCA) response as measured by Ki-67 expression between the pre-treatment tumor and the posttreatment tumor.

II. To identify biological characteristics of tumors (e.g. mismatch repair [MMR] status, PTEN mutational status, etc.) correlating with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

III. To determine the frequency of adverse events associated with use of abemaciclib and letrozole.

EXPLORATORY OBJECTIVES:

  1. To evaluate the correlation of the expression of Ki-67 with that of cyclin D1, p16, pRB, and PTEN as well as with MMR deficiency.

OUTLINE:

Patients receive letrozole orally (PO) once daily (QD) and abemaciclib PO twice daily (BID) on days 1-14. Patients then undergo standard of care hysterectomy on day 15.

After completion of study treatment, patients are followed up at 30 days and at 2 and 6 weeks after surgery.

What participants receive

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

Study groups in NCT04049227
Study groupRoleWhat they receive
Treatment (letrozole, abemaciclib)ExperimentalPatients receive letrozole PO QD and abemaciclib PO BID on days 1-14. Patients then undergo standard of care hysterectomy on day 15.
Receives: Drug: Abemaciclib; Drug: Letrozole; Procedure: Therapeutic Conventional Surgery

What is being measured

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

  1. Changes in Ki-67 expression

    Measured: Baseline up to 6 weeks

Secondary outcomes (7)

  1. Proportion of tumors with complete cell cycle arrest (CCCA) response

    Will be measured by Ki-67 between the pre-treatment tumor and the post-treatment tumor. CCCA response is defined as less than 3% of tumor cells staining positive for Ki-67 from specimens obtained at time of hysterectomy. Baseline biomarker levels will be compared between patients who do vs.

    do not achieve complete CCCA using a two-sample t-test.

    Measured: At day 15

  2. Biological characteristics of tumors: MMR status

    Will be measured to correlate with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

    Measured: Up to 6 weeks

  3. Biological characteristics of tumors: PTEN mutational status

    Will be measured to correlate with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

    Measured: Up to 6 weeks

  4. Biological characteristics of tumors: expression of cyclin D1

    Will be measured to correlate with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

    Measured: Up to 6 weeks

  5. Biological characteristics of tumors: p16

    Will be measured to correlate with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

    Measured: Up to 6 weeks

  6. Biological characteristics of tumors: pRB

    Will be measured to correlate with decreased Ki-67 expression induced by the letrozole and abemaciclib combination.

    Measured: Up to 6 weeks

  7. Incidence of adverse events associated with abemaciclib and letrozole

    Categorized and graded according to Common Terminology Criteria for Adverse Events (CTCAE) version (v)5.

    Measured: Up to 6 weeks

Timeline

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

  1. First posted8 Aug 2019
  2. Study start12 Aug 2019
  3. Primary completion1 Apr 2023
  4. Study completion15 May 2023

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
Early Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
27 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04049227
Sponsor's protocol ID
NU 18G07
Other IDs
STU00209370, NU 18G07, P30CA060553, NCI-2019-04599
Status last verified
Oct 2025
First submitted
31 Jul 2019
Last updated
20 Oct 2025
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 Early Phase 1 study testing Abemaciclib, Letrozole and Therapeutic Conventional Surgery in people with Endometrial Endometrioid Adenocarcinoma, run by Northwestern University at 2 sites 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 26 inclusion and 19 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: finished, as of the sponsor's last update on 20 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites 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?

Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.

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

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Changes in Ki-67 expression (time frame: Baseline up to 6 weeks). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04049227.

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 20 Oct 2025.

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