NCT04614194 · University of Texas Southwestern Medical Center
Single Cell Immune and Non-immune Correlates of Response to Neoadjuvant Abemaciclib
What this study is about
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.
View original scientific description
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.
Interventions
DRUG
Letrozole
Oral. Tablets should be taken at the same times every day, with or without food.
DRUG
Abemaciclib
Oral. Tablets should be taken at the same times every day, with or without food.
Primary outcome measures
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 deeme
Where
- Dallas, Texas
Collaborators
Eli Lilly and Company, Cancer Prevention Research Institute of Texas
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 17, 2026 · Source of record for eligibility and locations