Breast CancerPhase 2NCT04614194
Single Cell Immune and Non-immune Correlates of Response to Neoadjuvant Abemaciclib
A Phase 2 study testing Letrozole and Abemaciclib in people with Breast Cancer, run by University of Texas Southwestern Medical Center at 2 sites in United States.
Trial summary
The purpose of this study is to better understand how the immune system plays a role in fighting breast cancer and specifically research if the immune system response against breast cancer can be improved with endocrine therapy and cyclin dependent kinase inhibitor therapy in patients with hormone receptor positive… Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- Letrozole and Abemaciclib
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 2 sitesUnited States
- Study dates
- 15 Apr 2021to 15 Apr 2028
- 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
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Clinical stage operable stage I, II, or III invasive mammary carcinoma, which is estrogen receptor or progesterone receptor positive by immunohistochemistry and HER2 negative by Herceptest (0 or 1+) or not amplified by in situ hybridization as per routine clinical testing.
- Have post-menopausal status, as defined by any of the following: Subjects at least 55 years of age OR Subjects under 55 years of age and amenorrheic for at least 12 months OR follicule stimulating hormone (FSH) values ≥ 40 IU/L and estradiol levels ≤ 40 pg/mL (140 pmol/L) or in postmenopausal ranges per local or institutional reference ranges.
- Breast tumor ≥1cm in diameter by either physical exam or ultrasound and suitable for pre and post-treatment tissue sampling.
- Meet either of 2 following criteria, for which neoadjuvant endocrine therapy for 2 weeks is deemed suitable: 1) disease that is planned for surgery as initial therapy, in which 2 weeks of neoadjuvant endocrine therapy is deemed suitable, 2) Disease for which neoadjuvant systemic therapy (either chemotherapy or endocrine therapy) may be planned, in which 2 weeks of neoadjuvant endocrine therapy prior to start of systemic therapy is deemed suitable.
- At least 18 years of age
- Performance status ECOG ≤ 2
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- Have adequate organ function (ANC ≥1,500/mcL, Platelets ≥100,000/mcL, Hemoglobin ≥8 g/dL, Total bilirubin ≤1.5 × upper limit of normal, ALT and AST ≤3 × upper limit of normal, Creatinine clearance >30 mL/minute
- The patient is able to swallow oral medications
- Patients with a prior history of contralateral breast cancer are eligible if they have no evidence of recurrence of their initial primary breast cancer.
- Women may have been taking tamoxifen or raloxifene as a preventive agent prior to study entry but must have discontinued the drug for at least 28 days prior to study enrollment.
- Subjects have ended hormone replacement therapy at least 7 days prior to receiving the first dose of randomized therapy.
- Ability to understand and the willingness to sign a written informed consent.
- A female of childbearing potential, must have a negative serum pregnancy test within 7 days of the first dose of abemaciclib and agree to use a highly effective contraception method during the treatment period and for 3 weeks following the last dose of abemaciclib. These criteria should not apply to most or all patients on the trial given the inclusion criteria is for post-menopausal patients only who should not be of childbearing potential.
- Note: Contraceptive methods may include an intrauterine device [IUD] or barrier method. If condoms are used as a barrier method, a spermicidal agent should be added as a double barrier protection. Cases of pregnancy that occur during maternal exposures to abemaciclib should be reported. If a patient or spouse/partner is determined to be pregnant following abemaciclib initiation, she must discontinue treatment immediately. Data on fetal outcome and breast-feeding are to be collected for regulatory reporting and drug safety evaluation.
Who cannot join
- Active metastatic breast cancer, inflammatory breast cancer, or locally recurrent breast 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 a preexisting chronic condition resulting in baseline grade 2 or higher diarrhea).
- Females who are pregnant, lactating, or premenopausal.
- Severe uncontrolled malabsorption condition or disease (i.e. grade 2 or higher diarrhea, severe malnutrition, short gut syndrome).
- Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent.
- Chemotherapy, radiotherapy, or any other cancer therapy for current diagnosis of breast cancer.
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- Subjects may not have received or be receiving any other investigational agents for the treatment of the cancer under study.
- History of allergic reactions attributed to compounds of similar chemical or biologic composition to abemaciclib or other agents used in study.
- Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that, in the opinion of the investigator, would limit compliance with study requirements.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States2 sites, 2 recruiting
- Not yet recruiting
Parkland Hospital
Dallas, Texas, 75039
- Recruiting
University of Texas Southwestern Medical Center
Dallas, Texas, 75390
About this study
Official title: Single Cell Immune and Non-immune Correlates of Response to Neoadjuvant Abemaciclib and Letrozole in Hormone Receptor Positive Breast Cancer
The purpose of this study is to better understand how the immune system plays a role in fighting breast cancer and specifically research if the immune system response against breast cancer can be improved with endocrine therapy and cyclin dependent kinase inhibitor therapy in patients with hormone receptor positive breast cancer. This will be studied by collecting tumor tissue and blood samples before and after 2 weeks of study treatment with commonly used endocrine therapy and cyclin dependent kinase inhibitor therapy.
- Conditions
- Breast Cancer
- Being tested
- Letrozole, Abemaciclib
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LetrozoleDrug
Oral. Tablets should be taken at the same times every day, with or without food.
AbemaciclibDrug
Oral. Tablets should be taken at the same times every day, with or without food.
| Study group | Role | What they receive |
|---|---|---|
| Arm A: Abemaciclib + Letrozole | Experimental | Patient will take twice daily abemaciclib and daily letrozole (Arm A) for 2 weeks prior to your planned standard treatment for breast cancer. In addition to tests and procedures that are part of your standard care, you will have a biopsy and blood draw for study purposes prior to starting study treatment. Receives: Drug: Letrozole; Drug: Abemaciclib |
| Arm B: Letrozole | Experimental | Patient will take daily letrozole only (Arm B) according to treatment arm for 2 weeks prior to your planned standard treatment for breast cancer. In addition to tests and procedures that are part of your standard care, you will have a biopsy and blood draw for study purposes prior to starting study treatment. Receives: Drug: Letrozole |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in T cell activation
Change in T cell activation between matched pre-treatment and on-treatment tissue samples of responder patients treated with abemaciclib and letrozole. T cell activation will be defined as the density of granzyme positive CD8 T cells detected on multiplex immunohistochemistry. Responders are defined as having complete cell cycle arrest by Ki-67.
Measured: After treatment ends (14 (+/- 3) days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Nov 2020
- Study start15 Apr 2021
- Primary completion15 Apr 2027 (estimated)
- Study completion15 Apr 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by University of Texas Southwestern Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Texas Southwestern Medical Center
- Sponsor type
- University, hospital or other
- Collaborators
- Eli Lilly and Company, Cancer Prevention Research Institute of Texas
- Responsible party
- Principal investigator, Sangeetha Reddy, University of Texas Southwestern Medical Center
- Investigators
- Sangeetha Reddy, MD, Principal investigator, University of Texas Southwestern Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04614194
- Sponsor's protocol ID
- STU-2020-1043
- Status last verified
- May 2026
- First submitted
- 13 Oct 2020
- Last updated
- 17 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Single Cell Immune and Non-immune Correlates of Response to Neoadjuvant Abemaciclib and Letrozole in Hormone Receptor Positive Breast Cancer
- ClinicalTrials.gov ID
- NCT04614194
- Acronym / sponsor ID
- STU-2020-1043
- Conditions
- Breast Cancer
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- University of Texas Southwestern Medical CenterUniversity, hospital or other
- Collaborators
- Eli Lilly and Company, Cancer Prevention Research Institute of Texas
- Study start
- 15 Apr 2021 (actual)
- Primary completion
- 15 Apr 2027 (estimated)
- Study completion
- 15 Apr 2028 (estimated)
- First posted
- 3 Nov 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to better understand how the immune system plays a role in fighting breast cancer and specifically research if the immune system response against breast cancer can be improved with endocrine therapy and cyclin dependent kinase inhibitor therapy in patients with hormone receptor positive breast cancer. This will be studied by collecting tumor tissue and blood samples before and after 2 weeks of study treatment with commonly used endocrine therapy and cyclin dependent kinase inhibitor therapy.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Arm A: Abemaciclib + Letrozole | Experimental | Drug: Letrozole, Drug: AbemaciclibPatient will take twice daily abemaciclib and daily letrozole (Arm A) for 2 weeks prior to your planned standard treatment for breast cancer. In addition to tests and procedures that are part of your standard care, you will have a biopsy and blood draw for study purposes prior to starting study treatment. |
| Arm B: Letrozole | Experimental | Drug: LetrozolePatient will take daily letrozole only (Arm B) according to treatment arm for 2 weeks prior to your planned standard treatment for breast cancer. In addition to tests and procedures that are part of your standard care, you will have a biopsy and blood draw for study purposes prior to starting study treatment. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (14 listed)
- Clinical stage operable stage I, II, or III invasive mammary carcinoma, which is estrogen receptor or progesterone receptor positive by immunohistochemistry and HER2 negative by Herceptest (0 or 1+) or not amplified by in situ hybridization as per routine clinical testing.
- Have post-menopausal status, as defined by any of the following: Subjects at least 55 years of age OR Subjects under 55 years of age and amenorrheic for at least 12 months OR follicule stimulating hormone (FSH) values ≥ 40 IU/L and estradiol levels ≤ 40 pg/mL (140 pmol/L) or in postmenopausal ranges per local or institutional reference ranges.
- Breast tumor ≥1cm in diameter by either physical exam or ultrasound and suitable for pre and post-treatment tissue sampling.
- Meet either of 2 following criteria, for which neoadjuvant endocrine therapy for 2 weeks is deemed suitable: 1) disease that is planned for surgery as initial therapy, in which 2 weeks of neoadjuvant endocrine therapy is deemed suitable, 2) Disease for which neoadjuvant systemic therapy (either chemotherapy or endocrine therapy) may be planned, in which 2 weeks of neoadjuvant endocrine therapy prior to start of systemic therapy is deemed suitable.
- At least 18 years of age
Key exclusion criteria (9 listed)
- Active metastatic breast cancer, inflammatory breast cancer, or locally recurrent breast 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 a preexisting chronic condition resulting in baseline grade 2 or higher diarrhea).
- Females who are pregnant, lactating, or premenopausal.
- Severe uncontrolled malabsorption condition or disease (i.e. grade 2 or higher diarrhea, severe malnutrition, short gut syndrome).
- Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LetrozoleOral. Tablets should be taken at the same times every day, with or without food. | Drug | Arm A: Abemaciclib + Letrozole, Arm B: Letrozole |
| AbemaciclibOral. Tablets should be taken at the same times every day, with or without food. | Drug | Arm A: Abemaciclib + Letrozole |
Primary outcome
Change in T cell activation
Time frame: After treatment ends (14 (+/- 3) days
Change in T cell activation between matched pre-treatment and on-treatment tissue samples of responder patients treated with abemaciclib and letrozole. T cell activation will be defined as the density of granzyme positive CD8 T cells detected on multiplex immunohistochemistry. Responders are defined as having complete cell cycle arrest by Ki-67.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jun 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sangeetha Reddy, MD principal investigator
University of Texas Southwestern Medical Center
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Letrozole and Abemaciclib in people with Breast Cancer, run by University of Texas Southwestern Medical Center 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 14 inclusion and 9 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 17 Jun 2026. 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?
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 Shahbano Shakeel (214-648-7097, Shahbano.Shakeel@UTSouthwestern.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in T cell activation (time frame: After treatment ends (14 (+/- 3) days). 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 17 Jun 2026.