New drug combo may keep breast cancer from coming back

NCT ID NCT04584853

Disease control Sponsor: Institute of Cancer Research, United Kingdom Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This phase 3 trial tests whether adding the drug abemaciclib to standard hormone therapy can lower the chance of breast cancer returning in postmenopausal women with a high-risk type. About 123 participants will receive either hormone therapy alone or with abemaciclib for up to 2 years. The study focuses on women whose tumors show high growth activity after initial hormone treatment before surgery.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 3

Large-scale testing in a bigger group. Usually the last step before a treatment can be approved.

Participants

123 people

The number who actually took part.

Started

Dec 2020

Expected to finish

Oct 2030

An estimate. End dates often move.

Lead sponsor

Other sponsor

The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 years and older

Sex

Female participants only

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Registration Stage Inclusion Criteria: 1. Women determined to be postmenopausal according to established local criteria. 2. Diagnosed operable invasive breast cancer with a clinical/radiological tumour size ≥1.0cm\* 3. Grade 2 or 3 tumours 4. Preoperative full assessment completed (including bilateral breast examination and imaging with mammogram +/- ultrasound/MRI as performed locally). 5. Tumour ER positive. ER positivity is defined as \>/=1% cells staining positive (or equivalent Allred Score of ER \>/=3 out of 8). 6. Tumour HER2 negative or HER2 status unknown. HER2 negativity will be defined as per the 2018 ASCO/CAP updated guidelines. Patients whose HER2 status is pending/unknown at the time of registration will be allowed to register to the trial. However, please note that only patients who are confirmed to be HER2 negative will be eligible to join the randomised part. 7. Received or planned to receive 10 days to 6 months of anastrozole or letrozole prior to surgery. 8. Written informed consent to enter the registration stage of the trial and to donation of fresh tissue. 9. The patient has given written informed consent prior to any study-specific procedures and is willing and able to make herself available for the duration of the study and amenable and able to follow study schedule during treatment and follow-up and for the use of routinely collected electronic health and related records. Registration Stage Exclusion Criteria: 1. Men and pre/perimenopausal women. 2. Intended or actual use of HRT or any other oestrogen-containing medication (including vaginal oestrogens) within 4 weeks prior to planned surgery). Note: patient with a Mirena coil in situ at the time of registration are not excluded. 3. Patients who commenced pre-surgical AI therapy \>6 months prior to surgery. 4. Prior endocrine therapy for breast cancer or breast cancer prevention. 5. Prior neoadjuvant chemotherapy for breast cancer. 6. Evidence of metastatic disease. 7. Locally advanced breast cancer not amenable to surgery. 8. Bilateral invasive breast cancer (excluding contralateral DCIS/LCIS). 9. Multiple unilateral tumours with different ER and/or HER2 status. Synchronous DCIS/LCIS, as well as multifocal disease with homogenous ER/HER2 status is allowed if at least one lesion is at least 1.0cm; the largest lesion should be used for sample collection and CRF completion. If ER/HER2 status of smaller foci is unknown at time of registration, patients can be registered; however, note that congruity of receptor status will need to be confirmed by the time of randomisation, unless smaller foci are \<10mm and receptor status is unknown. 10. Previous invasive breast cancer except for ipsilateral DCIS or LCIS treated \>5 years previously by locoregional therapy alone or contralateral DCIS/LCIS treated by locoregional therapy at any time. 11. Any invasive malignancy diagnosed within previous 5 years (other than non-melanoma skin cancer or cervical carcinoma in situ). 12. Any other medical condition likely to exclude the patient from subsequent randomisation stage. (See exclusion criteria: Eligibility for Randomisation). Randomisation Stage Inclusion Criteria: 1. Patient previously consented and registered for screening component of POETIC-A. 2. Tumour HER2 negative. HER2 negativity will be defined as per the 2018 ASCO/CAP updated guidelines 3. Centrally confirmed Ki67 \>/=8% following 2 weeks of AI. 4. Patient is expected by the time of treatment initiation to have undergone definitive surgery for the primary breast tumour with clear radial margins as judged by the multidisciplinary team, and will have completed any adjuvant chemotherapy or radiotherapy (if prescribed). 5. Surgical staging of the axilla must have been undertaken by sentinel node biopsy, axillary sampling or dissection. 6. The patient is randomised in time for treatment to start no later than three months after completion of non-endocrine therapy (defined as the final fraction of radiotherapy, Day 1 of the final cycle of chemotherapy or the date of the final surgical procedure). 7. The patient is able to swallow oral medications (excluding transient side effects from adjuvant non-endocrine treatment, if randomised before the end of this treatment). 8. The patient intends to take adjuvant endocrine therapy for at least 5 years. 9. The patient has given written informed consent prior to any study-specific procedures (for the randomised intervention part), is willing to donate tissue from diagnostic biopsy, and is willing and able to make herself available for the duration of the study and to follow study schedule during treatment and follow-up and for the use of routinely collected electronic health and related records. Randomisation Stage Exclusion Criteria: 1. Patient has received prior CDK4/6 inhibitor. 2. Patient is planned to receive adjuvant abemaciclib as standard of care. 3. Any patient with a history of VTE (for example, DVT of the leg or arm and/or PE) will be excluded. Patients with a history of venous catheter occlusion by thrombus that did NOT surround the catheter, and the lumen could be made patent by appropriate measures (for example, saline or thrombolytic agent), are not excluded. 4. The patient has a serious/or uncontrolled pre-existing medical condition(s) that, in the judgment of the investigator, is likely to preclude study treatment (such as severe renal impairment, \[for example, estimated creatinine clearance \<30 mL/min\], interstitial lung disease, severe dyspnoea at rest or requiring oxygen therapy, history of major surgical resection involving the stomach or small bowel, or pre-existing Crohn's disease or ulcerative colitis or a pre-existing chronic condition resulting in baseline Grade 2 diarrhoea). 5. The patient has a personal history of any of the following conditions: syncope of cardiovascular aetiology, ventricular arrhythmia of pathological origin (including, but not limited to, ventricular tachycardia and ventricular fibrillation), or sudden cardiac arrest. Exception: patients with controlled atrial fibrillation diagnosed more than 30 days prior to randomisation are not excluded. 6. The patient has received an experimental treatment in a clinical trial within the last 30 days or 5 half-lives, whichever is longer, prior to randomisation, or is currently enrolled in any other type of medical research (for example: medical device) judged by the Chief Investigator not to be scientifically or medically compatible with this study. 7. The patient has any known active systemic bacterial infections (that would be expected to require IV antibiotics at time of initiating study treatment), systemic fungal infection or detectable viral infection (such as known HIV positivity or with known active hepatitis B or C, e.g. hepatitis B surface antigen positive) which would be expected to preclude study treatment. Screening is not required for enrolment. 8. Evidence of metastatic disease or local recurrence. 9. Multiple unilateral tumours with different ER and/or HER2 status (DCIS/LCIS are permitted, and confirmation of congruent ER/HER2 status is not necessary for lesions less than 10mm). Week 1 Day 1 Inclusion Criteria: 1. Patient must have undergone definitive surgery for the primary breast tumour with clear radial margins as judged by the multidisciplinary team. 2. Adjuvant chemotherapy, if prescribed, must have been completed prior to Week 1 Day 1, and patients must have recovered (Common Terminology Criteria for Adverse Events, version 5 \[CTCAE v5\] Grade ≤1) from the acute effects of chemotherapy except for residual alopecia or Grade 2 peripheral neuropathy prior to Week 1 Day 1. A washout period of a minimum of 28 days from day 1 of the last cycle of treatment is required. 3. Adjuvant radiotherapy, if prescribed, must have been completed prior to Week 1 Day 1, and patients must have recovered (Grade \</=1) from the acute effects of radiotherapy. A washout period of at least 14 days is required between end of radiotherapy and Week 1 Day 1. 4. Week 1 Day 1 is scheduled to take place no later than three months after completion of non-endocrine therapy (defined as the final fraction of radiotherapy, Day 1 of the final cycle of chemotherapy or the date of the final surgical procedure, whichever is latest). 5. The patient is able to swallow oral medications. 6. The patient has adequate organ function for all of the following criteria defined as: ANC \>/= 1.5 × 10e9/L (G-CSF cannot be administered to meet this ANC eligibility criterion); Platelets \>/= 100 × 10e9/L; Haemoglobin \>/= 8g/dL; Total bilirubin \</= 1.5 × ULN (Patients with Gilbert's syndrome with a total bilirubin ≤2.0 times ULN and direct bilirubin within normal limits are permitted); ALT and AST \</= 3 × ULN Week 1 Day 1 Exclusion Criteria: 1. Patient has received any CDK4/6 inhibitor therapy since randomisation. 2. Any newly occurring or diagnosed VTE since randomisation (for example, DVT of the leg or arm and/or PE). Note: patients with a history of venous catheter occlusion by thrombus that did NOT surround the catheter, and the lumen could be made patent by appropriate measures (for example, saline or thrombolytic agent), are not excluded. 3. Any newly occurring or diagnosed medical conditions since randomisation that, in the judgment of the investigator, would preclude participation in this study (such as severe renal impairment, \[for example, estimated creatinine clearance \<30 mL/min\], interstitial lung disease, severe dyspnoea at rest or requiring oxygen therapy, major surgical resection involving the stomach or small bowel, or condition resulting in baseline Grade 2 diarrhoea). 4. Any newly occurring or diagnosed cardiovascular conditions since randomisation such as: syncope of cardiovascular aetiology, ventricular arrhythmia of pathological origin (including, but not limited to, ventricular tachycardia and ventricular fibrillation), or sudden cardiac arrest. 5. Major surgery within 14 days prior to Week 1 Day 1. 6. The patient has received an experimental treatment in a clinical trial within the last 30 days or 5 half-lives, whichever is longer, prior to Week 1 Day 1, or is currently enrolled in any other type of medical research (for example: medical device) judged by the Chief Investigator not to be scientifically or medically compatible with this study. 7. Any active systemic bacterial infections (requiring IV antibiotics at time of Week 1 Day 1), systemic fungal infection or detectable viral infection (such as known HIV positivity or active hepatitis B or C, e.g. hepatitis B surface antigen positive). Screening is not required for initiation of treatment. 8. Evidence of metastatic disease or local recurrence

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Conditions

The condition(s) this trial relates to.

breast cancer female breast carcinoma

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Breast cancer female

Contacts and locations

Locations

Aberdeen Royal Infirmary

Aberdeen, United Kingdom
Barnet and Chase Farm Hospitals

London, United Kingdom
Belfast City Hospital

Belfast, Northern Ireland, United Kingdom
Blackpool Victoria Hospital

Blackpool, United Kingdom
Borders General Hospital

Melrose, United Kingdom
Burnley General Hospital

Burnley, BB10 2PQ, United Kingdom
Calderdale Royal Hospital

Halifax, United Kingdom
Charing Cross Hospital

London, United Kingdom
Doncaster Royal Infirmary

Doncaster, United Kingdom
Dumfries and Galloway Royal Infirmary

Dumfries, United Kingdom
East Surrey Hospital

Redhill, United Kingdom
Forth Valley Royal Hospital

Larbert, Scotland, FK5 4WR, United Kingdom
George Eliot Hospital NHS Trust

Nuneaton, United Kingdom
Glan Clwyd

Rhyl, United Kingdom
Great Western Hospital

Swindon, England, SN3 6BB, United Kingdom
Harrogate District Hospital

Harrogate, United Kingdom
Huddersfield Royal Infirmary

Huddersfield, United Kingdom
Ipswich Hospital

Ipswich, IP4 5PD, United Kingdom
Kettering General Hospital

Kettering, United Kingdom
Kingston Hospital

Kingston upon Thames, United Kingdom
Lincoln County Hospital

Lincoln, United Kingdom
Maidstone and Tunbridge Wells NHS Trust

Maidstone, United Kingdom
Mid Yorkshire -Pinderfields Hospital

Wakefield, WF1 4DG, United Kingdom
Milton Keynes University Hospital

Milton Keynes, United Kingdom
Musgrove Park Hospital

Taunton, United Kingdom
Ninewells Hospital

Dundee, United Kingdom
North Manchester General Hospital

Manchester, United Kingdom
North Tyneside General Hospital

North Shields, United Kingdom
Northampton General Hospital

Northampton, Northants, United Kingdom
Pilgrim Hospital

Boston, United Kingdom
Poole General Hospital

Poole, United Kingdom
Queen Elizabeth Hospital

Kings Lynn, England, PE30 4ET, United Kingdom
Royal Albert Edward Infirmary

Wigan, United Kingdom
Royal Berkshire Hospital

Reading, United Kingdom
Royal Blackburn Hospital

Blackburn, BB2 3HH, United Kingdom
Royal Bournemouth Hospital

Bournemouth, United Kingdom
Royal Cornwall Hospital

Truro, Cornwall, United Kingdom
Royal Devon & Exeter Hospital

Exeter, Devon, United Kingdom
Royal Free Hospital

London, United Kingdom
Royal Marsden Hospital

Sutton, United Kingdom
Royal Marsden NHS Foundation Trust

London, United Kingdom
Royal Shrewsbury Hospital

Shrewsbury, United Kingdom
Royal Stoke University Hospital

Stoke-on-Trent, United Kingdom
Royal Surrey County Hospital

Guildford, Surrey, GU2 7XX, United Kingdom
Royal Sussex County Hospital

Brighton, United Kingdom
Royal United Hospital Bath

Bath, United Kingdom
Southampton General Hospital

Southampton, SO166YD, United Kingdom
St George's Hospital

London, United Kingdom
St James's University Hospital

Leeds, United Kingdom
St John's Hospital

Livingston, United Kingdom
The Beatson West of Scotland Cancer Centre

Glasgow, United Kingdom
The Christie Hospital

Manchester, United Kingdom
University College London

London, United Kingdom
University Hospital Llandough

Penarth, United Kingdom
University Hospitals of Morecambe Bay

Lancaster, United Kingdom
University Hospitals of North Tees and Hartlepool

Stockton-on-Tees, United Kingdom
Wansbeck General Hospital

Ashington, United Kingdom
Warwick Hospital

Warwick, United Kingdom
Western General Hospital

Edinburgh, United Kingdom
Worcestershire Acute Hospitals NHS Trust

Worcester, United Kingdom
Wythenshawe Hospital

Manchester, United Kingdom
Ysbyty Gwynedd

Bangor, United Kingdom

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