The POWER Trial: Personalised Dose Optimisation With Adjuvant Tamoxifen Therapy in Breast cancER (NCT07502820) | Clinical Trial Compass
Not Yet RecruitingPhase 3
The POWER Trial: Personalised Dose Optimisation With Adjuvant Tamoxifen Therapy in Breast cancER
Sweden1,100 participantsStarted 2026-03
Plain-language summary
In Sweden, approximately 7000 women are diagnosed with hormone-sensitive breast cancer annually. According to international and national guidelines, most of these women are recommended anti-hormonal therapy for five to ten years to improve prognosis. Tamoxifen, one of the most widely used anti-hormonal agents globally, reduces the risk of recurrence by 40% and breast cancer mortality by 30%.
Tamoxifen is a pro-drug that undergoes hepatic metabolism to form endoxifen and other active metabolites. Variability in metabolic capacity affects therapeutic efficacy: poor metabolisers produce insufficient endoxifen and other active metabolites, risking therapeutic failure, while ultrarapid metabolisers generate excessive amounts, leading to intolerable adverse effects. Today, 30-50% of patients discontinue treatment prematurely due to severe side effects, resulting in suboptimal outcomes.
Currently, tamoxifen is uniformly prescribed at a daily dose of 20 mg, and so far, no clinical trials have tested whether individualised dosing could enhance adherence and improve survival outcomes. The primary objective is to evaluate whether individualised tamoxifen dosing reduces discontinuation rates and enhances patient outcomes in breast cancer treatment.
Who can participate
Age range
18 Years
Sex
FEMALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
* Patients with primary breast cancer, recommended for adjuvant tamoxifen treatment with or without concomitant goserelin
* Premenopausal or perimenopausal, defined according to SOC for therapy decision
* Eastern Cooperative Oncology Group (ECOG) WHO Performance Scale 0 - 2
* Participants must use non-hormonal contraception during the trial.
Exclusion Criteria:
* Previous use of tamoxifen, endoxifen, or aromatase inhibitors.
* Previous medical history of:
Deep venous thrombosis or pulmonary embolism; bleeding disorder or coagulopathy; macular disorders, retinal disorders, severe cataract or glaucoma.
* Current use of warfarin.
* Not willing to abstain from strong and moderate CYP2D6 inhibitors or CYP3A4 inducers during the tamoxifen treatment
* Current pregnancy, breastfeeding, or already at start of tamoxifen planning to become pregnant within the next two years
* Use of systemic menopausal hormonal therapy (MHT).
* Prior invasive malignancy during the last five years. Prior or current in situ cancers are allowed.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Discontinuation of tamoxifen.
Timeframe: From enrollment to end of treatment at 60 months.