A Phase 1/2 interventional study of Anastrozole and Palbociclib in Breast Neoplasms and Breast Diseases, sponsored by Icahn School of Medicine at Mount Sinai. Active, not recruiting at 5 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-29.
Sponsored by Icahn School of Medicine at Mount Sinai · Phase 1/2, Interventional, and Treatment
Among 111 studies testing anastrozole in Breast Neoplasms — 17 open to participants now, 28 under way, 10 of them phase 3. Anastrozole · Breast Neoplasms.
Among the 111 studies testing anastrozole in Breast Neoplasms, this one is the 80th largest by enrollment of the 109 interventional ones, is one of 5 that started in 2017, is the only one in phase 1/2, reaches primary completion later than 13 of the 27 other live ones, and was the 84th registered.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's enrollment of 44 is below the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →17 of the 111 studies testing anastrozole in Breast Neoplasms are open now, in 4 countries. Each count lists the studies.
Anastrozole: first FDA approval 1995 (ARIMIDEX). What it is approved for, and how studies give it, is on its page →
Of the 2,400 Breast Neoplasms studies recruiting now, 1,572 (66%) set no upper age limit and 591 (25%) stop at 75 or younger; 103 take children under 18; 214 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →On this site’s reading of the record, anastrozole is the treatment under test here. Read study by study →
111 studies; the count open now beside each. This study's row is marked.
First in 1996; this study’s year is marked. 5 started in 2017.
Median enrollment 148 across the 109 interventional studies. Of the 67 that completed or were terminated, 30 (45%) have results posted.
21 of 111 have an industry lead sponsor. The 10 most frequent:
Icahn School of Medicine at Mount Sinai is the lead sponsor of 776 studies on the registry; 176 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 83 (66%) have results posted.
18 studies in Breast Neoplasms by Icahn School of Medicine at Mount Sinai: 3 open now, 4 under way, none of them phase 3. Of 14 finished, 3 (21%) have results posted.
Among the 18 studies in Breast Neoplasms by Icahn School of Medicine at Mount Sinai, this one is the 13th largest by enrollment of the 17 interventional ones, is the only one that started in 2017, is one of 3 in phase 1/2, and was the 10th registered.
Icahn School of Medicine at Mount Sinai’s Breast Neoplasms studies by the year they started, since 2004.
4 of the studies testing anastrozole in Breast Neoplasms that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT01953588Phase 3Alliance for Clinical Trials in OncologyFulvestrant and/or Anastrozole in Treating Postmenopausal Patients With Stage II-III Breast Cancer Undergoing Surgery | 2027-04-01 |
| NCT04553770Jonsson Comprehensive Cancer CenterTrastuzumab Deruxtecan Alone or in Combination With Anastrozole for the Treatment of Early Stage HER2 Low, Hormone Receptor Positive Breast Cancer | 2026-12-31 |
| NCT02476786Washington University School of MedicineEndocrine Treatment Alone for Elderly Patients With Estrogen Receptor Positive Operable Breast Cancer and Low Recurrence Score | 2027-01-31 |
| NCT03304080Icahn School of Medicine at Mount SinaiAnastrozole, Palbociclib, Trastuzumab and Pertuzumab in HR-positive, HER2-positive Metastatic Breast | 2027-07-31 |
Among the 111 studies testing anastrozole in Breast Neoplasms, from their registry updates:
Among Icahn School of Medicine at Mount Sinai’s 18 in Breast Neoplasms:
This is a multicenter, phase I/II trial of anastrozole, palbociclib, trastuzumab, and pertuzumab is proposed as first-line therapy in metastatic hormone receptor-positive, HER2-positive breast cancer patients. In this phase I/II clinical trial, the researchers aim to establish the safety and efficacy of dual HER2 therapy in combination with palbociclib and anastrozole, which represents a novel and all biologic approach to the treatment of HR+, HER2+ metastatic breast cancer. Additionally, the researchers aim to examine potential biomarkers of response to palbociclib including cyclin D1, cyclin E1 and cyclin E2 expression levels, CDK 2, 4, and 6 levels, phosphorylated retinoblastoma expression and p16 levels. The researchers intend to use RNA sequencing to assess for other predictors of response in an unbiased manner to see if this correlates with inhibition of Ki-67 and phosphorylated retinoblastoma expression as well as evaluate for potential mechanisms of resistance.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
status or receiving ovarian ablation with a GnRH agonist such as goserelin or leuprolide. Postmenopausal status is defined by any one of the following criteria:
Note: Recommended methods of birth control are: The consistent use of an intrauterine device (IUD), double barrier methods (diaphragm with spermicidal gel or condoms with contraceptive foam), sexual abstinence (no sexual intercourse) or sterilization.
Men must agree to use a condom and not father a child for the duration of the study and for 90 days after completion of therapy
Laboratory values (≤ 28 days prior to registration)
Exclusion Criteria:
Patients who have any severe and/or uncontrolled medical conditions or other conditions that could affect their participation in the study such as:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
RECIST
The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.
“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Absolute neutrophil count (ANC)
The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.
It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Leptomeningeal disease
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Reproductive potential
Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.
Criteria about it usually ask for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Women and men with HR-positive, HER2-positive Metastatic Breast Cancer on trial of anastrozole, palbociclib, trastuzumab and pertuzumab
Drug: Anastrozole · Drug: Palbociclib · Drug: Trastuzumab · Drug: Pertuzumab
1 mg orally daily, day 1 to day 28
Also known as: Arimidex
Dose I: 100 mg orally daily, day 1 to day 21, then 7 days off in a 28 day cycle (Phase 1 only) Dose II: 125 mg orally daily, day 1 to day 21, then 7 days off in a 28 day cycle
Also known as: Ibrance
8 mg/kg IV initial loading dose, followed by 6 mg/kg IV every 21 days
Also known as: Herceptin
840 mg IV followed by a maintenance dose of 420 mg IV every 21 days
Also known as: Perjeta
Dose-Limiting Toxicity (DLT)
The dose-limiting toxicity (DLT) for palbociclib when administered in combination with anastrozole, trastuzumab and pertuzumab. A DLT will be defined as: * Grade 3 or 4 non-hematologic toxicity * Grade 3 neutropenia lasting greater than 21 days * Grade 3 or 4 neutropenia with neutropenic fever or * Grade 4 hematologic toxicity events experienced within the first 4 weeks (1 cycle) of study treatment. These will be assessed via the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI's CTCAE) v4.0 toxicity criteria.
Time frame: up to 3 months
Maximum Tolerated Dose (MTD)
The maximum tolerated dose (MTD) for palbociclib when administered in combination with anastrozole, trastuzumab and pertuzumab. If \> 33 % of patients experience a dose limiting toxicity (DLT) at any dose level, the dose level below that level will be considered the MTD. Or if the highest level has been reached and ≤ 33% of patients have experienced dose limiting toxicity (DLT), that will be considered the MTD.
Time frame: up to 3 months
Clinical Benefit Rate (CBR)
CBR will be measured by the percentage of patients whose cancer shrinks or remains stable over the duration of the study. This will be measured as the sum of complete response, partial response, and stable disease for greater than or equal to 6 months.
Time frame: average of 6 months
Progression Free Survival
The time from the start of treatment until confirmed disease progression or death from any cause, whichever occurs first.
Time frame: 2 years
Incidence of adverse events
incidence of adverse events as graded by the NCI CTCAE v4.0
Time frame: 2 years
Plan to share: Yes — Data collected during the course of this clinical trial will primarily be shared with other investigators and University staff, the IRB, FDA, and other reporting agencies, and/or transferred to other collaborators. Prior to transfer, the data collected must comply with, and must be limited by, the MSH's guidelines for Protecting the Rights and Privacy of Human Subjects.
No publications or documents are linked to this record.
Started Dec 2017 (actual). Primary completion is estimated for Jul 2027, 115 months after the start.
Of 166 non-industry phase 1/2 interventional studies under Breast Neoplasms, half reached primary completion within 64 months of starting (the median), counting those still running; a quarter within 45 and three quarters within 95. This study's planned 115 months is above that.
Counting every sponsor, half of 327 studies reached it within 61 months; a quarter within 45 and three quarters within 88.
How these figures are worked out, and which studies are left out of them.
This study is active, not recruiting, as verified in Jul 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
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Studies of the drugs tested here: Anastrozole · Palbociclib · Trastuzumab · Pertuzumab
Icahn School of Medicine at Mount Sinai →