Trial reportClinical pharmacokinetics2022
Therapeutic Drug Monitoring of Endoxifen for Tamoxifen Precision Dosing: Feasible in Patients with Hormone-Sensitive Breast Cancer.
Trial report in Clinical pharmacokinetics, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05501158 (CYP2D6 Genotypes and Breast Cancer Clinical Outcomes in the Indonesian Population), which is not on this map. Cited by 21 papers.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
CYP2D6 Genotypes and Breast Cancer Clinical Outcomes in the Indonesian Population (Pengaruh Genotipe CYP2D6 Terhadap Efektivitas Penggunaan Tamoksifen Untuk Pasien Kanker Payudara ER+ Pada Populasi Indonesia)
Who cites it
21 citing papers in PubMed, 29 citations in OpenAlex.
- Factors affecting inter-individual variability in endoxifen concentrations in patients with breast cancer: results from the prospective TOTAM trial.Breast cancer research and treatment · 2022Trial
- Preliminary results using a kit to measure tamoxifen and metabolites concentrations in capillary blood samples from women with breast cancer.Scientific reports · 2022Trial
- Rhubarb water extract as a promising gastroprotective agent in Tamoxifen induced parietal cell damage in female rats: a histological study.Anatomy & cell biology · 2025Article
- From Genotype to Therapeutic Monitoring: Enhancing Tamoxifen Efficacy in Breast Cancer Treatment.Journal of clinical pharmacology · 2025Article
- Therapeutic Drug Monitoring of Oral Targeted Anticancer Drugs: Achievements, Experiences, Challenges, and the Path Forward.Therapeutic drug monitoring · 2025Review
- Impact of Complex Genetic and Drug-Drug Interactions on Tamoxifen Metabolism and Efficacy.Journal of personalized medicine · 2025Review
- Article
- Effects of tamoxifen on cognitive function in patients with primary breast cancer.British journal of cancer · 2025Article
- Article
- Endoxifen Concentration Is Associated with Recurrence-Free Survival in Hormone-Sensitive Breast Cancer Patients.Cancer research and treatment · 2025Article
- Reasons for non-feasibility of therapeutic drug monitoring of oral targeted therapies in oncology - an analysis of the closed cohorts of a multicentre prospective study.British journal of cancer · 2024Article
- Review
- Cost-Effectiveness Analysis of MammaPrintPharmacoEconomics · 2023Article
- Effects of Genetic Polymorphisms of Drug Metabolizing Enzymes and co-Medications on Tamoxifen Metabolism in Black South African Women with Breast Cancer.Clinical pharmacology and therapeutics · 2023Article
- Tamoxifen pharmacokinetics and pharmacodynamics in older patients with non-metastatic breast cancer.Breast cancer research and treatment · 2023Article
- Development and validation of a liquid chromatography-mass spectrometry assay for quantification of Z- and E- isomers of endoxifen and its metabolites in plasma from women with estrogen receptor positive breast cancer.Journal of chromatography. B, Analytical technologies in the biomedical and life sciences · 2023Article
- The impact of endoxifen-guided tamoxifen dose reductions on endocrine side-effects in patients with primary breast cancer.ESMO open · 2023Article
- Tamoxifen evolution.British journal of cancer · 2023Review
- Pharmacokinetics of Tamoxifen and Its Major Metabolites and the Effect of the African Ancestry Specific CYP2D6*17 Variant on the Formation of the Active Metabolite, Endoxifen.Journal of personalized medicine · 2023Article
- Tamoxifen use and potential effects on liver parenchyma: A long-term prospective transient elastographic evaluation.Hepatology communications · 2022Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
14 authors at 6 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundEndoxifen is the most important active metabolite of tamoxifen. Several retrospective studies have suggested a minimal or threshold endoxifen systemic concentration of 14-16 nM is required for a lower recurrence rate. The aim of this study was to investigate the feasibility of reaching a predefined endoxifen level of ≥ 16 nM (5.97 ng/mL) over time using therapeutic drug monitoring (TDM).
methodsThis prospective open-label intervention study enrolled patients who started treatment with a standard dose of tamoxifen 20 mg once daily for early breast cancer. An outpatient visit was combined with a TDM sample at 3, 4.5, and 6 months after initiation of the tamoxifen treatment. The tamoxifen dose was escalated to a maximum of 40 mg if patients had an endoxifen concentration < 16 nM. The primary endpoint of the study was the percentage of patients with an endoxifen level ≥ 16 nM at 6 months after the start of therapy compared with historical data, in other words, 80% of patients with endoxifen levels ≥ 16 nM with standard therapy.
resultsIn total, 145 patients were included. After 6 months, 89% of the patients had endoxifen levels ≥ 16 nM, compared with a literature-based 80% of patients with endoxifen levels ≥ 16 nM at baseline (95% confidence interval 82-94; P = 0.007). In patients with an affected CYP2D6 allele, it was not always feasible to reach the predefined endoxifen level of ≥ 16 nM. No increase in tamoxifen-related adverse events was reported after dose escalation.
conclusionThis study demonstrated that it is feasible to increase the percentage of patients with endoxifen levels ≥ 16 nM using TDM. TDM is a safe strategy that offers the possibility of nearly halving the number of patients with endoxifen levels < 16 nM.
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