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Breast CancerPhase 2PREcoopERANCT05896566

A Window-of-Opportunity Trial of Giredestrant +/- Triptorelin vs. Anastrozole + Triptorelin in Premenopausal Patients With ER-positive/HER2-negative Early Breast Cancer

A Phase 2 study testing Giredestrant, Triptorelin and Anastrozole in people with Breast Cancer, run by ETOP IBCSG Partners Foundation at 37 sites in 6 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

PREcoopERA is a randomized (2:2:1), multicenter, open-label, three-arm (A, B, C), Window-of-Opportunity (WOO) trial to evaluate the activity and safety of giredestrant (A) versus giredestrant plus triptorelin (B) versus anastrozole plus triptorelin (C). 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?
Giredestrant, Triptorelin and Anastrozole
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
231 participants
Where
37 sitesin 6 countries
Study dates
23 Jan 2024to 18 Sep 2025
Phase
Phase 2
Are there results?
None posted in the registry

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

  • Premenopausal women age ≥18 years, premenopausal status defined as:
  • Estradiol (E2) in the premenopausal range (according to institution parameters) or Patient has been menstruating regularly during the 6 months prior to screening and has not used any form of hormonal contraception or any other hormonal treatments during this time.
  • Histologically confirmed, operable invasive breast carcinoma.
  • Eligible for upfront breast conservative surgery or upfront mastectomy: stage I, stage II or operable stage III (excludes T4) (AJCC Cancer Staging Manual 8th edition 2017).46 Tumor size must be ≥1.0 cm Multicentric and multifocal tumors and bilateral breast cancers are allowed but investigators must ensure the same tumor foci is biopsied pre-treatment and post-treatment (e.g., via clipping of the biopsied tumor foci).
  • Documented estrogen receptor (ER)-positive tumor in accordance to ASCO/CAP guidelines (Allison et al. 2020),47 assessed locally and defined as ≥1% of tumor cells stained positive.
  • Documented human epidermal growth factor receptor-2 (HER2)-negative tumor in accordance to 2018 ASCO/CAP guidelines (Wolff et al. 2018)48, as determined per local assessment.
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  • Ki 67 ≥10% in diagnostic biopsy as determined per local assessment.
  • Eastern Cooperative Oncology Group Performance Status 0-1.
  • Resting heart rate ≥40 bpm.
  • Normal hematologic status
  • Normal renal function
  • Normal liver function
  • INR <1.5× ULN and PTT <1.5x ULN Except for patients receiving anticoagulation therapy. For patients receiving warfarin, a stable INR between 2 and 3 is required. For patients receiving heparin, PTT between 1.5 and 2.5 x ULN (or value before patient started heparin treatment) is required.
  • If anticoagulation therapy is required for a prosthetic heart valve, stable INR between 2.5 and 3.5 is permitted.
  • Negative serum or urine beta HCG pregnancy test within 5 weeks prior to randomization.
  • Pregnancy test will be repeated on day 1, before the first dose of WOO treatment.
  • Women of childbearing potential must use highly effective contraceptive methods during the treatment period and for 10 days after the final dose.
  • Written Informed Consent (IC) must be signed and dated by the patient and the Investigator prior to randomization.
  • The patient has been informed of and agrees to data transfer and handling, in accordance with national data protection guidelines.
  • The patient agrees to the submission of tumor (diagnostic pre-treatment core biopsy and post-treatment re-biopsy) and blood samples for central pathology review (CPR) and for translational studies as part of this protocol.

Who cannot join

  • Stage IV (metastatic) breast cancer.
  • Inflammatory breast cancer (cT4d).
  • Previous systemic or local treatment for the primary breast cancer currently under investigation.
  • Received any GnRH/LHRH analog within 12 months prior to randomization
  • Major surgery within 4 weeks prior to randomization.
  • Known clinically significant history of liver disease consistent with Child-Pugh Class B or C, including hepatitis.
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  • Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigator, would make the patient inappropriate for entry into this study.
  • History of documented hemorrhagic diathesis, coagulopathy, or thromboembolism.
  • Active cardiac disease or history of cardiac dysfunction, including any of the following:
  • History or presence of symptomatic bradycardia or resting heart rate <50 bpm at screening. Patients on stable dose of a beta-blocker or calcium channel antagonist for pre-existing baseline conditions (e.g., hypertension) may be permitted if resting heart rate is ≥50 bpm.
  • History of angina pectoris, symptomatic pericarditis, myocardial infarction, or any cardiac arrhythmias (e.g., ventricular, supraventricular, nodal arrhythmias, or conduction abnormality) within 12 months prior to study entry History of documented congestive heart failure (New York Heart Association Class II-IV) or cardiomyopathy Left ventricular ejection fraction <50% as determined by multiple-gated acquisition scan or echocardiogram QT interval corrected through use of Fridericia's formula (QTcF) >470 ms based on mean value of triplicate ECGs, history of long or short QT syndrome, Brugada syndrome or known history of corrected QT interval prolongation, or torsades de pointes History or presence of an abnormal ECG that is clinically significant in the investigator's opinion, including complete left bundle branch block, second- or third-degree heart block, sick sinus syndrome, or evidence of prior myocardial infarction
  • History of ventricular dysrhythmias or risk factors for ventricular dysrhythmias such as structural heart disease (e.g., severe left ventricular systolic dysfunction, left ventricular hypertrophy), coronary heart disease (symptomatic or with ischemia demonstrated by diagnostic testing), clinically significant electrolyte abnormalities (e.g., hypokalemia, hypomagnesemia, hypocalcemia), or family history of long QT syndrome.
  • Current treatment with medications that are well known to prolong the QT interval.
  • Treatment with strong CYP3A4 inhibitors or inducers within 14 days or 5 drug elimination half-lives (whichever is longer) prior to initiation of study treatment.
  • Known issues with swallowing oral medication.
  • Active inflammatory bowel disease or chronic diarrhea, short bowel syndrome, or major upper gastrointestinal surgery including gastric resection.
  • Serious infection requiring oral or IV antibiotics, or other clinically significant infection within 14 days prior to screening.
  • Any active tumor of non-breast-cancer histology.
  • Women who are pregnant or in the period of lactating.
  • Any concurrent disease or serious medical condition or abnormality in clinical laboratory tests that, in the investigator's judgment, precludes the patient's safe participation in and completion of the study.
  • Judgement by the investigator that the patient should not participate in the study if the patient is unlikely to comply with study procedures, restrictions and requirements.
  • Contraindications or known hypersensitivity to the trial medication or excipients.
  • Treatment with any investigational agents within 30 days prior to expected start of trial treatment.

Trial locations and contacts

37 sites in 6 countries.

37 sites in 6 countries

Italy11 sites

  • Clinica Oncologica AOU Riuniti Ancona

    Ancona

  • Humanitas Gavazzeni

    Bergamo

  • ASL BR Azienda Sanitaria Locale

    Brindisi

  • IRCCS Ospedale Policlinico San Martino

    Genova

  • Istituto oncologico romagnolo per lo studio dei tumori "Dino Amadori"

    Meldola

  • Istituto Europeo di Oncologia

    Milan

  • AOU maggiore della carita

    Novara

  • Istituti Clinici Scientifici Maugeri SpA-SB

    Pavia

  • Azienda USL Toscana Centro

    Prato

  • Rimini Oncology department

    Rimini

  • Policlinico universitario Agostino Gemelli IRCCS Rome

    Roma

Other trials in Italy

Germany10 sites

  • HELIOS Klinikum Berlin Buch

    Berlin

  • Praxisklinik Krebsheilkunde formerly MediOnko-Institut GbR

    Berlin

  • KEM / Kliniken Essen Mitte

    Essen

  • Klinikum der J. W. Goethe Universität

    Frankfurt

  • Universitätsklinikum Schleswig-Holstein

    Kiel

  • St. Elisabeth Krankenhaus

    Leipzig

  • Universitätsklinikum Mannheim GmbH

    Mannheim

  • Klinikum Südstadt

    Rostock

  • Universitätsklinikum Ulm

    Ulm

  • Helios Klinikum Wuppertal GmbH

    Wuppertal

Other trials in Germany

Switzerland8 sites

  • Kantonsspital Baden AG

    Baden

  • Praxis Dr. Thorn, Praxis fur ambulante Tumortherapie (Praxis Thorn (Bethesda))

    Basel

  • Onc Inst of Southern Switzerland (IOSI)

    Bellinzona

  • Centre du Sein (Hopital Fribourgeois-Freiburger Spital)

    Fribourg

  • La Chaux-de-fonds, RH Neuchatelois (Hopital Les Cadolles)

    La Chaux-de-Fonds

  • St. Anna Hirslanden

    Lucerne

  • Brustzentrum Thurgau ( Spital AG)

    Thurgau

  • Universitiy Hospital Zurich

    Zurich

Other trials in Switzerland

Spain5 sites

  • Institut Catala D'oncologia ICO-Badalona

    Badalona

  • Institut Catala d'Oncologia - Hospitalet

    Barcelona

  • CIOCC (Centro Integral Oncológico Clara Campal)

    Madrid

  • Hospital Universitari Son Espases

    Palma de Mallorca

  • H. la Fé

    Valencia

Other trials in Spain

Ireland2 sites

  • St. James Hospital

    Dublin

  • University Hospital Galway

    Galway

Other trials in Ireland

France1 site

  • Gustave Roussy Cancer Center

    Villejuif

Other trials in France

About this study

PREcoopERA is a randomized (2:2:1), multicenter, open-label, three-arm (A, B, C), Window-of-Opportunity (WOO) trial to evaluate the activity and safety of giredestrant (A) versus giredestrant plus triptorelin (B) versus anastrozole plus triptorelin (C).

Read the detailed description

The primary objectives are:

  • to determine if 4 weeks of giredestrant plus triptorelin provides greater anti-proliferative activity than anastrozole plus triptorelin among premenopausal patients with ER-positive/HER2-negative operable invasive breast cancer.
  • to determine if 4 weeks of giredestrant without triptorelin provides anti-proliferative activity that is similar (non-inferior) to giredestrant plus triptorelin among premenopausal patients with ER-positive/HER2-negative operable invasive breast cancer.
Conditions
Breast Cancer
Being tested
Giredestrant, Triptorelin, Anastrozole
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • GiredestrantDrug

    Giredestrant: 30 mg daily, PO from day 1 until the day of re-biopsy/surgery.

  • TriptorelinDrug

    Triptorelin: 3.75 mg IM on day 1. Note: If re-biopsy/surgery cannot be done on day 29 (±3 days) from the first injection, then a second dose of triptorelin should be given on day 29 (±3 days).

  • AnastrozoleDrug

    Anastrozole: 1 mg daily, PO from day 1 until the day of re-biopsy/surgery.

Study groups in NCT05896566
Study groupRoleWhat they receive
Arm A: GiredestrantExperimentalGiredestrant
Receives: Drug: Giredestrant
Arm B: Giredestrant plus triptorelinExperimentalGiredestrant plus triptorelin
Receives: Drug: Giredestrant; Drug: Triptorelin
Arm C: Anastrozole plus triptorelinActive comparatorAnastrozole plus triptorelin
Receives: Drug: Triptorelin; Drug: Anastrozole

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in Ki 67

    The primary endpoint is the change in Ki 67 (Ki 67-labeling index, the percentage immunostaining cells measured by IHC in central laboratory) between the pre-treatment tumor biopsy and a post-treatment tumor re-biopsy (analyzed on the natural logarithm scale).

    Measured: From date of randomisation until 29 ±3 days post-randomisation

Secondary outcomes (2)

  1. Complete cell cycle arrest (CCCA)

    Complete cell cycle arrest (CCCA), defined as Ki 67 ≤2.7% on the post -treatment tumor re-biopsy on day 29 (±3 days), by visual image analysis.

    Measured: From date of randomisation until 29 ±3 days post-randomisation

  2. Adverse events according to CTCAE v5.0

    Record all AEs (including SAEs and AESIs) and assign the appropriate grade according to the CTCAE v5.0.

    Measured: From the date of enrolment until last patient last visit (approximately 28 months after randomisation of the first patient)]

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted9 Jun 2023
  2. Study start23 Jan 2024
  3. Primary completion18 Sep 2025
  4. Study completion18 Sep 2025

Resources

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
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Window of opportunity trial with no therapeutic intent, no efficacy.
Masking
None (open label)
Enrolment
231 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05896566
Sponsor's protocol ID
IBCSG 67-22
Acronym
PREcoopERA
Status last verified
Feb 2026
First submitted
31 May 2023
Last updated
24 Feb 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Giredestrant, Triptorelin and Anastrozole in people with Breast Cancer, run by ETOP IBCSG Partners Foundation at 37 sites in 6 countries.

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 20 inclusion and 23 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: finished, as of the sponsor's last update on 24 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 37 sites in Italy, Germany, Switzerland, Spain, Ireland and 1 more country. 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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in Ki 67 (time frame: From date of randomisation until 29 ±3 days post-randomisation). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05896566.

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 24 Feb 2026.

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