Therapeutic Drug Monitoring guided tamoxifen dosing: a feasibility study in patients with hormone positive breast cancer

Status

Not yet recruiting

Phases

Phase 4

Study type

Interventional

Source

EU CTR

Registry ID

EUCTR2017-005124-24-NL

Enrollment

400

Registered

2018-01-16

Start date

2018-01-31

Completion date

Unknown

Last updated

2022-03-02

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Hormone positive breast cancer

Interventions

Trade Name: tamoxifen Pharmaceutical Form: Tablet

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Adult women (= 18 years of age) who are planned to start adjuvant tamoxifen therapy. 2. WHO Performance Status = 1 3. Able and willing to sign the Informed Consent Form prior to screening evaluations 4. Able and willing to undergo blood sampling for PK analysis. Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range 200 F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range 200

Exclusion criteria

Exclusion criteria: 1. Woman who are pregnant or breast feeding; 2. Endometrial cancer (diagnosis 20 mg OD.

Design outcomes

Primary

Measure	Time frame
Main Objective: To prove that TDM of tamoxifen is feasible in clinical practice.;Secondary Objective: 1. To determine the relation between the pharmacokinetics (PK) of tamoxifen and its metabolites and relevant adverse effects. 2. To investigate the effects of TDM on patient compliance, based on validated questionnaires. 3. To prove that TDM of tamoxifen is cost effective in clinical practice. 4. To investigate the incidence of non-alcoholic fatty liver disease after 2 years of tamoxifen therapy. 5. To investigate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 6. To investigate the effects of lowering the tamoxifen dose in patients with severe side effects and an endoxifen concentration of >32 nmol/L on the level of adverse effects. 7. To evaluate the effect of two year tamoxifen treatment on objective and subjective cognitive functioning, measured by validated online cognitive tests and questionnaires and to investigate the association between tamoxifen dose, tamoxifen plasma concentrations and cognitive functioning. ;Primary end point(s): The percentage of patients with an adequate TDM target level (endoxifen blood level =16 nmol/L) at month 6 after start of tamoxifen treatment in comparison with the percentage patients with an adequate TDM target level (endoxifen blood level =16 nmol/L) at month 1 after start of tamoxifen treatment.;Timepoint(s) of evaluation of this end point: After 6 months .	—

Measure

Time frame

Main Objective: To prove that TDM of tamoxifen is feasible in clinical practice.;Secondary Objective: 1. To determine the relation between the pharmacokinetics (PK) of tamoxifen and its metabolites and relevant adverse effects. 2. To investigate the effects of TDM on patient compliance, based on validated questionnaires. 3. To prove that TDM of tamoxifen is cost effective in clinical practice. 4. To investigate the incidence of non-alcoholic fatty liver disease after 2 years of tamoxifen therapy. 5. To investigate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 6. To investigate the effects of lowering the tamoxifen dose in patients with severe side effects and an endoxifen concentration of >32 nmol/L on the level of adverse effects. 7. To evaluate the effect of two year tamoxifen treatment on objective and subjective cognitive functioning, measured by validated online cognitive tests and questionnaires and to investigate the association between tamoxifen dose, tamoxifen plasma concentrations and cognitive functioning. ;Primary end point(s): The percentage of patients with an adequate TDM target level (endoxifen blood level =16 nmol/L) at month 6 after start of tamoxifen treatment in comparison with the percentage patients with an adequate TDM target level (endoxifen blood level =16 nmol/L) at month 1 after start of tamoxifen treatment.;Timepoint(s) of evaluation of this end point: After 6 months .

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Secondary

Measure	Time frame
Secondary end point(s): 1. To determine the safety (Adverse Events) in relation with pharmacokinetic parameters, such as endoxifen steady state concentrations) of TDM guided dosing. 2. To determine the patient compliance and quality of life after 1, 6 and 24 months after start tamoxifen treatment in comparison with the baseline. We will evaluate compliance with the MORISKY 8 scale scores during this intervention study. 3. To evaluate the direct medical costs needed to monitor all patients to adequately adjust subtherapeutic patients. To determine the Quality of Life after 1, 6 and 24 months after start tamoxifen treatment in comparison with the baseline, we will evaluate Quality of Life with the EORTC QLQ BR23 questionnaire 4. To evaluate the incidence of non-alcoholic fatty liver disease 24 months after start of tamoxifen treatment in comparison with the baseline (0-3 months after start of tamoxifen treatment) 5. To evaluate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 4. To evaluate the incidence of non-alcoholic fatty liver disease 24 months after start tamoxifen treatment in comparison with the baseline (0-3 months after start tamoxifen treatment. 5. To evaluate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 6. To investigate the effects of lowering the tamoxifen dose in patients with severe side effects and an endoxifen concentration of >32 nmol/L on the level of adverse effects. 7. The difference in the age-corrected scores on each cognitive subtest and the score of self-reported cognition between patients on two-year tamoxifen treatment and healthy controls. 8. The association between tamoxifen dose, plasma concentrations of tamoxifen and endoxifen and score on each cognitive subtest and the score of self-reported cognition. ;Timepoint(s) of evaluation of this end point: End of the study	—

Measure

Time frame

Secondary end point(s): 1. To determine the safety (Adverse Events) in relation with pharmacokinetic parameters, such as endoxifen steady state concentrations) of TDM guided dosing. 2. To determine the patient compliance and quality of life after 1, 6 and 24 months after start tamoxifen treatment in comparison with the baseline. We will evaluate compliance with the MORISKY 8 scale scores during this intervention study. 3. To evaluate the direct medical costs needed to monitor all patients to adequately adjust subtherapeutic patients. To determine the Quality of Life after 1, 6 and 24 months after start tamoxifen treatment in comparison with the baseline, we will evaluate Quality of Life with the EORTC QLQ BR23 questionnaire 4. To evaluate the incidence of non-alcoholic fatty liver disease 24 months after start of tamoxifen treatment in comparison with the baseline (0-3 months after start of tamoxifen treatment) 5. To evaluate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 4. To evaluate the incidence of non-alcoholic fatty liver disease 24 months after start tamoxifen treatment in comparison with the baseline (0-3 months after start tamoxifen treatment. 5. To evaluate the effects of food on the pharmacokinetics (PK) of tamoxifen and its metabolites. 6. To investigate the effects of lowering the tamoxifen dose in patients with severe side effects and an endoxifen concentration of >32 nmol/L on the level of adverse effects. 7. The difference in the age-corrected scores on each cognitive subtest and the score of self-reported cognition between patients on two-year tamoxifen treatment and healthy controls. 8. The association between tamoxifen dose, plasma concentrations of tamoxifen and endoxifen and score on each cognitive subtest and the score of self-reported cognition. ;Timepoint(s) of evaluation of this end point: End of the study

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Countries

Netherlands

Contacts

Public ContactS.L.W. Koolen

Erasmus MC

s.koolen@erasmusmc.nl

Outcome results

None listed

Source: EU CTR (via WHO ICTRP) · Data processed: Feb 4, 2026