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.
- 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
- 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
- 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
- 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.
- Active metastatic breast cancer, inflammatory breast cancer, or locally recurrent
- 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
- 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.