A Phase 2 interventional study of Letrozole and Chemotherapy in Breast Neoplasms, sponsored by Borstkanker Onderzoek Groep. Active, not recruiting at 29 sites in Netherlands. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-01.
Sponsored by Borstkanker Onderzoek Groep · Phase 2, Interventional, and Treatment
Among 390 studies in Breast Neoplasms with a site in Netherlands — 71 open to participants now, 117 under way, 35 of them phase 3. Breast Neoplasms · Netherlands.
Among the 390 studies in Breast Neoplasms with a site in Netherlands, this one is the 190th largest by planned enrollment of the 314 interventional ones that give a count, is one of 17 that started in 2019, is one of 63 in phase 2, reaches primary completion later than 7 of the 116 other live ones, and was the 231st registered.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
Browse Breast Neoplasms studies →71 of the 390 studies in Breast Neoplasms with a site in Netherlands are open now. Recruiting first, the newest first:
Maastricht University Medical Center · Sites in Netherlands
Novartis Pharmaceuticals · Sites in Netherlands
Novartis Pharmaceuticals · Sites in Netherlands, United States, Canada and 6 more countries
UMC Utrecht · Sites in Netherlands, Denmark, Germany and 1 more country
SPCTR · Sites in Netherlands
A study can be open while its sites in Netherlands have not opened yet or have stopped. Only those recruiting at a site in Netherlands →
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 · female · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
390 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 57 · Phase 2 87 · Phase 3 111 · Phase 4 6
First in 1992; this study’s year is marked. 17 started in 2019.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 100 is above the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Median enrollment 189 across the 314 interventional studies, 205 across the 72 observational. Of the 243 that completed or were terminated, 71 (29%) have results posted.
This tab as a report to print or save as PDF → With an account.
153 of 390 have an industry lead sponsor. The 10 most frequent:
Borstkanker Onderzoek Groep is the lead sponsor of 8 studies on the registry; none are open to participants now.
Borstkanker Onderzoek Groep has 8 studies filed under Breast Neoplasms — fewer than ten, so there is no comparison to draw.
22 of the studies in Breast Neoplasms with a site in Netherlands that are under way reach primary completion within a year, 5 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT05774951Phase 3AstraZenecaA Study of Camizestrant in ER+/HER2- Early Breast Cancer After at Least 2 Years of Standard Adjuvant Endocrine Therapy | 2027-04-20 |
| NCT06312176Phase 3Merck Sharp & Dohme LLCA Study of Sacituzumab Tirumotecan (MK-2870) as a Single Agent and in Combination With Pembrolizumab (MK-3475) Versus Treatment of Physician's Choice in Participants With HR+/HER2- Unresectable Locally Advanced or Metastatic Breast Cancer (MK-2870-010) | 2027-07-11 |
| NCT07062965Phase 3PfizerA Study to Learn About the Study Medicine Called PF-07248144 in Combination With Fulvestrant in People With HR-positive, HER2-negative Advanced or Metastatic Breast Cancer Who Progressed After a Prior Line of Treatment. | 2027-07-22 |
| NCT05514054Phase 3Eli Lilly and CompanyA Study of Imlunestrant Versus Standard Endocrine Therapy in Participants With Early Breast Cancer | 2027-10 |
| NCT05950945Phase 3Daiichi SankyoTrastuzumab Deruxtecan (T-DXd) in Patients Who Have Hormone Receptor-negative and Hormone Receptor-positive HER2-low or HER2 IHC 0 Metastatic Breast Cancer | 2027-10-01 |
Among the 390 studies in Breast Neoplasms with a site in Netherlands, from their registry updates:
This tab as a report to print or save as PDF → With an account.
The aim of this prospective, randomized, multicenter, open-label, phase II study is to test if chemotherapy can be replaced by the combination of ribociclib plus letrozole as a neo-adjuvant therapy for patients with non-metastatic primary luminal breast cancer.
Based on Ki67 levels after two weeks of initial letrozole treatment in postmenopausal patients with hormone receptor positive, HER2 negative, stage II/III breast cancer, patients are either advised to continue letrozole treatment (if Ki67 \<1%) or will be randomized between standard chemotherapy (AC-T) or ribociclib in combination with letrozole (if Ki67 ≥1%).
Inclusion Criteria:
Inclusion criteria randomization specific:
In order to be eligible to be randomized in this study, a subject must meet all of the following criteria:
Exclusion Criteria:
Currently receiving any of the following substances and cannot be discontinued 7 days prior to randomisation:
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.
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).
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.
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
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.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
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.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
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.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
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.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
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.
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.
Measurable disease
The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.
The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.
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.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
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.
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.
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.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
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.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
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.
All patients initially start with two weeks of letrozole treatment. Patients with a Ki67 of \<1% in the biopsy taken after those two weeks of treatment are advised to stay on letrozole treatment until surgery. However, treatment choice is free.
Drug: Letrozole
All patients initially start with two weeks of letrozole treatment. Patients with a Ki67 of ≥1% in the biopsy taken after those two weeks of treatment are randomized between chemotherapy (standard AC-T chemotherapy) or ribociclib plus letrozole (ribociclib 600 mg/day (days 1-21, q4 weeks) plus letrozole 2.5 mg daily (days 1-28, q4 weeks)).
Drug: Chemotherapy
All patients initially start with two weeks of letrozole treatment. Patients with a Ki67 of ≥1% in the biopsy taken after those two weeks of treatment are randomized between chemotherapy (standard AC-T chemotherapy) or ribociclib plus letrozole (ribociclib 600 mg/day (days 1-21, q4 weeks) plus letrozole 2.5 mg daily (days 1-28, q4 weeks)).
Drug: Ribociclib plus letrozole
Letrozole 2.5 mg daily.
Dose dense AC-T chemotherapy: consisting of 4 cycles of AC (doxorubicin and cyclophosphamide at a dose of 60 and 600 mg/m² as an i.v. bolus, respectively) 2-weekly, plus G-CSF (6 mg once per cycle) 24-48 hr after chemotherapy, followed by cycles of T (4 cycles docetaxel 100 mg/m² 3-weekly or 12 cycles paclitaxel 80 mg/m2 weekly).
Ribociclib 600 mg/day (days 1-21, q4 weeks) plus letrozole 2.5 mg daily (days 1-28, q4 weeks).
This study also gives Ribociclib. No intervention listed here names it: that was found by reading the record.
Difference in complete cell cycle arrest (CCCA; defined as Ki67 IHC <1%) between ribociclib plus letrozole and chemotherapy in the surgical specimen.
Determine if ribociclib plus letrozole gives a ≥100% improvement in CCCA as compared to chemotherapy in the surgical specimen.
Time frame: CCCA will be determined in the surgical specimen, which is around 7 months after start of initial letrozole treatment.
Correlation between Ki67 IHC scored manually, IHC scored automatically (Vectra ® 3) and Ki67 mRNA.
The correlation between the different Ki67 measurements will be determined in the primary core biopsy, two weeks biopsy and surgical specimen.
Time frame: Ki67 measurements will be done in the primary core biopsy (baseline), two weeks biopsy (done after two weeks of initial letrozole treatment) and the surgical specimen (which is around 7 months after start of initial letrozole treatment).
Correlation between ER pathway activity at baseline, after two weeks letrozole and at surgery and clinical outcome.
The ER pathway activity will be determined in the primary core biopsy, two weeks biopsy and surgical specimen and then correlated with clinical outcome. Activity will be determined using a Bayesian network model of the ER transcriptional program, which interprets the pathway target genes' mRNA levels (from Affymetrix HG-U133Plus2.0 arrays) and infers a probability that the ER pathway is active in a certain sample.
Time frame: ER pathway activity will measured in the primary core biopsy (baseline), two weeks biopsy (done after two weeks of initial letrozole treatment) and the surgical specimen (which is around 7 months after start of initial letrozole treatment).
Difference in pathologic response (pCR and response according to Miller and Payne) between the randomized study arms.
The pathologic response will be determined in the surgical specimen of the patients in the randomized study arms where after the difference between the two groups can be determined.
Time frame: pCR and response according to Miller and Payne will be determined in the surgical specimen, which is around 7 months after start of initial letrozole treatment.
Change in tumor biology and biomarkers (ER, PR, HER2, Rb, Ki67) at baseline, after 2 weeks letrozole and at surgery.
Tumor biology and biomarkers will be determined in the primary core biopsy, two weeks biopsy and surgical specimen, where after the change in tumor biology and biomarkers over time can be determined.
Time frame: Tumor biology and biomarkers will be assessed in the primary core biopsy (baseline), two weeks biopsy (done after two weeks of initial letrozole treatment) and the surgical specimen (which is around 7 months after start of initial letrozole treatment).
Toxicity according to NCI CTCAE v4.03 all grades and grade III/IV.
Toxicities are graded according to NCI CTCAE v4.03.
Time frame: Toxicity will be assessed from start treatment up to 30 days following the last dose of treatment.
Correlation of tumor measurements between standard MRI (using RECIST 1.1) and palpation (largest diameter in cm) at baseline, after AC/before T or 8 weeks of definitive neoadjuvant therapy and pre-surgery.
The correlation of tumor measurements between MRI and palpation will be determined at three different time points.
Time frame: Tumor measurements (MRI and palpation) will be performed at baseline, after AC/before T or 8 weeks of definitive neoadjuvant therapy and pre-surgery (which is around 7 months after start of initial letrozole treatment).
Descriptive analysis of event free survival (EFS) at 3 and 5 years.
EFS is defined as the time from randomization to the first date of local, regional, or distant relapse, second primary invasive breast cancer including contralateral breast cancer, progression according to RECIST 1.1 or death due to any cause which ever occurred first.
Time frame: EFS will be determined after 3 and 5 years.
Descriptive analysis of overall survival (OS) at 3 and 5 years.
OS is defined as the time from randomization to date of death.
Time frame: Time Frame: OS will be determined after 3 and 5 years.
Change in ERα DNA binding signatures (Chip-seq) between baseline and after 2 weeks letrozole.
ERα DNA binding will be determined in the primary core biopsy and two weeks biopsy, where after the change in these measurements over time can be determined.
Time frame: ERα DNA binding signatures will be assessed in the primary core biopsy (baseline) and the two weeks biopsy (done after two weeks of initial letrozole treatment).
Change in gene expression profiles (RNA-seq) between baseline and after 2 weeks letrozole.
Gene expression profiling will be determined in the primary core biopsy and two weeks biopsy, where after the change in these measurements over time can be determined.
Time frame: Gene expression profiles will be assessed in the primary core biopsy (baseline) and the two weeks biopsy (done after two weeks of initial letrozole treatment).
Plan to share: Undecided
Ran from Jun 2019 to primary completion in Dec 2022, 41 months.
Of 1,070 non-industry phase 2 interventional studies under Breast Neoplasms, half reached primary completion within 56 months of starting (the median), counting those still running; a quarter within 34 and three quarters within 87. This study's 41 months is below that.
Counting every sponsor, half of 1,302 studies reached it within 51 months; a quarter within 30 and three quarters within 82.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is active, not recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Ribociclib
Borstkanker Onderzoek Groep