Clinical trial • Phase III • Oncology

TAMOXIFEN for Breast cancer

Phase III trial of TAMOXIFEN for Breast cancer.

Overview

Trial Therapeutic Area
Oncology
Trial Disease
Breast cancer
Trial Stage
Phase III
Drug Modality
Small molecule

Key dates

Initial CTIS Submission Date
05-06-2025
First CTIS Authorization Date
02-09-2025

Trial design

Randomised, open-label, standard regimen: tamoxifen 20 mg per day (standard of care) compared to personalised dosing of tamoxifen (10 mg, 20 mg or 40 mg per day).-controlled Phase III trial across 9 sites in Sweden.

Randomised
Yes
Open Label
Yes
Comparator
Standard regimen: Tamoxifen 20 mg per day (standard of care) compared to personalised dosing of tamoxifen (10 mg, 20 mg or 40 mg per day).
Target Sample Size
1100

Eligibility

Recruits 1100 No vulnerable population selected. Participants are adults (Women aged ≥18 years). "Able and willing to give their written consent to participate in the trial" is required..

Pregnancy Exclusion
Current pregnancy, breastfeeding, or already at start of tamoxifen planning to become pregnant within the next two years
Vulnerable Population
No vulnerable population selected. Participants are adults (Women aged ≥18 years). "Able and willing to give their written consent to participate in the trial" is required.

Inclusion criteria

  • {"criterion_text":"-Patients with primary breast cancer, recommended for adjuvant tamoxifen treatment with or without concomitant goserelin"}
  • {"criterion_text":"-Women aged ≥18 years"}
  • {"criterion_text":"-Premenopausal or perimenopausal, defined according to SOC för therapy decisions"}
  • {"criterion_text":"-ECOG WHO PS 0 – 2"}
  • {"criterion_text":"-Participants must use non-hormonal contraception during the trial. A pregnancy test is recommended for women of child-bearing potential who are sexually active and not using reliable contraceptive methods before inclusion"}
  • {"criterion_text":"-Able and willing to undergo blood sampling according to study protocol"}
  • {"criterion_text":"-Able and willing to give their written consent to participate in the trial"}

Exclusion criteria

  • {"criterion_text":"-Previous use of tamoxifen, endoxifen, or aromatase inhibitors"}
  • {"criterion_text":"-Uncontrolled intercurrent physical or psychiatric illness, or social situations that would limit compliance with protocol requirements"}
  • {"criterion_text":"-Prior invasive malignancy during the last five years. Prior or current in situ cancers are allowed"}
  • {"criterion_text":"-Participation in another clinical drug trial"}
  • {"criterion_text":"-Inability to understand the study related information"}
  • {"criterion_text":"-Concomitant treatment with adjuvant CDK 4/6 inhibitors or capecitabine or trastuzumab emansine."}
  • {"criterion_text":"-Previous medical history of: Deep venous thrombosis or pulmonary embolism if not on life-long anticoagulant treatment with DOAC. A history of previous PICC-line or subcutaneous venous port associated thrombosis or superficial thrombophlebitis is allowed. Bleeding disorder or coagulopathy. Macular disorders, retinal disorder, severe cataract or glaucoma."}
  • {"criterion_text":"-Current use of warfarin. Antiaggregants’ and direct oral anticoagulants are allowed"}
  • {"criterion_text":"-Not willing to abstain from strong and moderate CYP2D6 inhibitors or CYP3A4 inducers during the tamoxifen treatment"}
  • {"criterion_text":"-Strong and moderate inhibitors of CYP2D6 not allowed in the trial: Bupropion (Zyban), Duloxetin (Cymbalta), Fluoxetin (Fontex), Levemopromazin (Nozinan), Mirabegron (Betmiga), Paroxetin (Seroxat), Terbinafin (Lamisil) for systemic use."}
  • {"criterion_text":"-CYP3A4 inducers not allowed in the trial (D-interactions in “Janusmedicin” janusmed.se): Efavirenz, Fenobarbital, Fenytoin, Johannesört, Karbamazepin, Primidon, Rifampicin, rifamycin."}
  • {"criterion_text":"-Current pregnancy, breastfeeding, or already at start of tamoxifen planning to become pregnant within the next two years"}
  • {"criterion_text":"-Use of systemic menopausal hormonal therapy (MHT) and all types of systemic hormonal contraception. Local treatment is acceptable"}

Endpoints

Primary endpoints

  • {"endpoint_text":"-The primary endpoint is discontinuation of tamoxifen.","definition_or_measurement_approach":""}

Secondary endpoints

  • {"endpoint_text":"-BESS plus (2007) scale and subscales and the POWER symptom questionnaire","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Quality of life questionnaire","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Concentration of circulating plasma metabolites","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Invasive disease-free survival (iDSF), Distant relapse-free survival (DRFS), Breast cancer specific survival (BCSS)","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Overall survival (OS)","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Mammographic breast density","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Cost effectiveness and use of health care resources","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Genetic polymorphisms in germline DNA","definition_or_measurement_approach":""}
  • {"endpoint_text":"-Biomarkers used for therapeutic drug monitoring","definition_or_measurement_approach":""}

Recruitment

Planned Sample Size
1100
Recruitment Window Months
128
Consent Approach
Written informed consent is required from participants. Participants are adults (women aged ≥18 years). No information on assent or multiple-language documents is provided in the available record.

Geography

Total Number Of Sites
9
Total Number Of Participants
1100

Sweden

Earliest CTIS Part Ii Submission Date
13-06-2025
Latest Decision Or Authorization Date
02-09-2025
Processing Time Days
81
Number Of Sites
9
Number Of Participants
1100

Sites

Site Name
Capio S:t Goerans Sjukhus AB
Department Name
Surgery and Oncology
Contact Person Name
Jenny Bergqvist
Site Name
Sahlgrenska University Hospital-Vaestra Goetalandsregionen
Department Name
Surgery
Contact Person Name
Jenny Heiman
Contact Person Email
jenny.heiman@vgregion.se
Site Name
Region Oerebro Laen
Department Name
Oncology
Contact Person Name
Antonis Valachis
Contact Person Email
antonios.valachis@oru.se
Site Name
Soedra Aelvsborg Hospital Vaestra Goetalandsregionen
Department Name
Medicine
Contact Person Name
Rebecka Landin
Contact Person Email
rebecka.landin@vgregion.se
Site Name
Soedersjukhuset AB
Department Name
Oncology
Contact Person Name
Linda Thorén
Site Name
Region Skane Skanes Universitetssjukhus
Department Name
Hematology, Oncology and radiation physics
Contact Person Name
Kristin Sigurjónsdóttir
Site Name
Malarsjukhuset Eskilstuna
Department Name
Oncology
Contact Person Name
Andreas Nearchou
Site Name
Skaraborg Hospital-Vaestra Goetalandsregionen
Department Name
Oncology
Contact Person Name
Chaido Chamalidou
Contact Person Email
chaido.chamalidou@vgregion.se
Site Name
Region Joenkoepings Laen
Department Name
Oncology
Contact Person Name
Maria Ekholm
Contact Person Email
maria.ekholm@rjl.se

Sponsor

Primary sponsor

Full Name
Karolinska Institutet
Organisation Type
Educational Institution
Country Of Registered Address
Sweden

Investigational products

Investigational Product Name
Tamoxifen Viatris 20 mg tabletter.
Active Substance
TAMOXIFEN
Modality
Small molecule
Routes Of Administration
ORAL
Route
Oral
Authorisation Status
Marketing authorisation (SE), marketingAuthNumber 10443
Starting Dose
Standard 20 mg per day; trial includes personalised dosing options
Dose Levels
10 mg per day | 20 mg per day | 40 mg per day
Frequency
Once daily
Maximum Dose
40 mg per day
Dose Escalation Increase
Initial and following doses: 10 mg, 20 mg, 40 mg (personalised dosing arms)
Combination Treatment
Yes

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