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Buijs SM, Koolen SLW, Mathijssen RHJ, Jager A. Tamoxifen Dose De-Escalation: An Effective Strategy for Reducing Adverse Effects? Drugs 2024; 84:385-401. [PMID: 38480629 PMCID: PMC11101371 DOI: 10.1007/s40265-024-02010-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2024] [Indexed: 05/19/2024]
Abstract
Tamoxifen, a cornerstone in the adjuvant treatment of estrogen receptor-positive breast cancer, significantly reduces breast cancer recurrence and breast cancer mortality; however, its standard adjuvant dose of 20 mg daily presents challenges due to a broad spectrum of adverse effects, contributing to high discontinuation rates. Dose reductions of tamoxifen might be an option to reduce treatment-related toxicity, but large randomized controlled trials investigating the tolerability and, more importantly, efficacy of low-dose tamoxifen in the adjuvant setting are lacking. We conducted an extensive literature search to explore evidence on the tolerability and clinical efficacy of reduced doses of tamoxifen. In this review, we discuss two important topics regarding low-dose tamoxifen: (1) the incidence of adverse effects and quality of life among women using low-dose tamoxifen; and (2) the clinical efficacy of low-dose tamoxifen examined in the preventive setting and evaluated through the measurement of several efficacy derivatives. Moreover, practical tools for tamoxifen dose reductions in the adjuvant setting are provided and further research to establish optimal dosing strategies for individual patients are discussed.
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Affiliation(s)
- Sanne M Buijs
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3015 CN, Rotterdam, The Netherlands.
| | - Stijn L W Koolen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3015 CN, Rotterdam, The Netherlands
- Department of Clinical Pharmacy, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Ron H J Mathijssen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3015 CN, Rotterdam, The Netherlands
| | - Agnes Jager
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3015 CN, Rotterdam, The Netherlands
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2
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El-Tanani M, Al Khatib AO, Al-Najjar BO, Shakya AK, El-Tanani Y, Lee YF, Serrano-Aroca Á, Mishra V, Mishra Y, Aljabali AA, Goyal R, Negi P, Farani MR, Binabaj MM, Gholami A, Binabaj MM, Charbe NB, Tambuwala MM. Cellular and molecular basis of therapeutic approaches to breast cancer. Cell Signal 2023; 101:110492. [PMID: 36241056 DOI: 10.1016/j.cellsig.2022.110492] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/03/2022] [Accepted: 10/05/2022] [Indexed: 11/29/2022]
Abstract
In recent decades, there has been a significant amount of research into breast cancer, with some important breakthroughs in the treatment of both primary and metastatic breast cancers. It's a well-known fact that treating breast cancer is still a challenging endeavour even though physicians have a fantastic toolset of the latest treatment options at their disposal. Due to limitations of current clinical treatment options, traditional chemotherapeutic drugs, and surgical options are still required to address this condition. In recent years, there have been several developments resulting in a wide range of treatment options. This review article discusses the cellular and molecular foundation of chemotherapeutic drugs, endocrine system-based treatments, biological therapies, gene therapy, and innovative techniques for treating breast cancer.
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Affiliation(s)
- Mohamed El-Tanani
- Pharmacological and Diagnostic Research Centre, Al-Ahliyya Amman University, Faculty of Pharmacy, Amman, Jordan; Centre for Cancer Research and Cell Biology, Queen's University Belfast, Grosvenor Road, Belfast BT12 6BJ, Northern Ireland, UK; Institute of Cancer Therapeutics, Faculty of Life Sciences, University of Bradford, Bradford, UK.
| | - Arwa Omar Al Khatib
- Pharmacological and Diagnostic Research Centre, Al-Ahliyya Amman University, Faculty of Pharmacy, Amman, Jordan
| | - Belal O Al-Najjar
- Pharmacological and Diagnostic Research Centre, Al-Ahliyya Amman University, Faculty of Pharmacy, Amman, Jordan
| | - Ashok K Shakya
- Pharmacological and Diagnostic Research Centre, Al-Ahliyya Amman University, Faculty of Pharmacy, Amman, Jordan
| | - Yahia El-Tanani
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, Grosvenor Road, Belfast BT12 6BJ, Northern Ireland, UK; Institute of Cancer Therapeutics, Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Yin-Fai Lee
- School of Pharmacy and Pharmaceutical Science, Ulster University, Coleraine BT52 1SA, UK; School of Life Sciences, Faculty of Science and Engineering, Anglia Ruskin University, Cambridge CB1 1PT, UK; Neuroscience, Psychology & Behaviour, College of Life Sciences, University of Leicester, Leicester LE1 9HN, UK
| | - Ángel Serrano-Aroca
- Biomaterials and Bioengineering Laboratory, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, c/Guillem de Castro 94, 46001 Valencia, Spain
| | - Vijay Mishra
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Yachana Mishra
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara 144411, Punjab, India
| | - Alaa A Aljabali
- Department of Pharmaceutics and Pharmaceutical Technology, Yarmouk University, Irbid 566, Jordan
| | - Rohit Goyal
- School of Pharmaceutical Sciences, Shoolini University of Biotechnology & Management Sciences, Solan 173229, India
| | - Poonam Negi
- School of Pharmaceutical Sciences, Shoolini University of Biotechnology & Management Sciences, Solan 173229, India
| | - Marzieh Ramezani Farani
- Toxicology and Diseases Group (TDG), Pharmaceutical Sciences Research Center (PSRC), the Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), 1417614411 Tehran, Iran.
| | - Maryam Moradi Binabaj
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Amir Gholami
- Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Maryam Moradi Binabaj
- Student Research Committee, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Nitin B Charbe
- Center for pharmacometrics and system pharmacology, department of pharmaceutics, college of pharmacy, University of Florida, FL, USA
| | - Murtaza M Tambuwala
- School of Pharmacy and Pharmaceutical Science, Ulster University, Coleraine BT52 1SA, UK; Neuroscience, Psychology & Behaviour, College of Life Sciences, University of Leicester, Leicester LE1 9HN, UK.
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3
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Braal CL, Jager A, Hoop EOD, Westenberg JD, Lommen KMWT, de Bruijn P, Vastbinder MB, van Rossum-Schornagel QC, Thijs-Visser MF, van Alphen RJ, Struik LEM, Zuetenhorst HJM, Mathijssen RHJ, Koolen SLW. Therapeutic Drug Monitoring of Endoxifen for Tamoxifen Precision Dosing: Feasible in Patients with Hormone-Sensitive Breast Cancer. Clin Pharmacokinet 2021; 61:527-537. [PMID: 34786650 PMCID: PMC8975771 DOI: 10.1007/s40262-021-01077-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2021] [Indexed: 02/08/2023]
Abstract
Background Endoxifen 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). Methods This 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. Results In 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. Conclusion This 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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Affiliation(s)
- C Louwrens Braal
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Agnes Jager
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Esther Oomen-de Hoop
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Justin D Westenberg
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Koen M W T Lommen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Peter de Bruijn
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Mijntje B Vastbinder
- Department of Internal Medicine, IJsselland Hospital, Capelle aan den IJssel, The Netherlands
| | | | - Martine F Thijs-Visser
- Department of Internal Medicine, Ikazia Hospital, Rotterdam, The Netherlands.,Department of Internal Medicine, Spijkenisse MC, Spijkenisse, The Netherlands
| | - Robbert J van Alphen
- Department of Internal Medicine, Elisabeth Tweesteden Hospital, Tilburg, The Netherlands
| | - Liesbeth E M Struik
- Department of Internal Medicine, Ikazia Hospital, Rotterdam, The Netherlands
| | | | - Ron H J Mathijssen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands
| | - Stijn L W Koolen
- Department of Medical Oncology, Erasmus MC Cancer Institute, Dr. Molewaterplein 40, PO Box 2040, 3000 CA, Rotterdam, The Netherlands. .,Department of Hospital Pharmacy, Erasmus University Medical Center, Rotterdam, The Netherlands.
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4
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Chan CWH, Law BMH, Ng MSN, Wong CCY, Wong CWY, Quinley M, Orgusyan JM, Chow KM, Waye MMY. Association of single nucleotide polymorphisms of cytochrome P450 enzymes with experience of vasomotor, vaginal and musculoskeletal symptoms among breast cancer patients: a systematic review. BMC Cancer 2021; 21:570. [PMID: 34006247 PMCID: PMC8130378 DOI: 10.1186/s12885-021-08268-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 04/28/2021] [Indexed: 02/20/2023] Open
Abstract
Background Adjuvant endocrine therapies are known to induce undesirable adverse effects such as vasomotor, vaginal and musculoskeletal symptoms among breast cancer patients. Drugs used in these therapies are often metabolised by cytochrome P450 (CYP) enzymes, in which their metabolising activities can be modified by single nucleotide polymorphisms (SNP) in CYP genes and CYP genotypes. This review aims to explore whether SNPs or genotypes of CYP are associated with the occurrence, frequency and severity of vasomotor, vaginal and musculoskeletal symptoms in breast cancer patients on adjuvant endocrine therapies. Methods A literature review was conducted using five electronic databases, resulting in the inclusion of 14 eligible studies, and their findings were presented narratively. Selected items from the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist were used for critical appraisal of the reporting quality of the included studies. Results Most of the included studies showed that SNPs or genotypes of CYP that modify its metabolising activity have no effect on the occurrence, frequency or severity of vasomotor symptoms, including hot flashes. One study showed no correlation of these genetic variations in CYP with musculoskeletal symptoms, and no data were available on the association between such genetic variations and vaginal symptoms. Conclusions Overall, genetic variations in CYP have no effect on the experience of hot flashes among breast cancer patients. We recommend exploration of the link between the active metabolites of chemotherapeutic drugs and the molecules shown to affect the occurrence or severity of hot flashes, and the establishment of the relationship between such genetic variations and patients’ experience of musculoskeletal and vaginal symptoms. Subgroup analyses based on patients’ duration of adjuvant endocrine therapies in such studies are recommended.
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Affiliation(s)
- Carmen W H Chan
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, the New Territories, Hong Kong SAR, China.,The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Bernard M H Law
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, the New Territories, Hong Kong SAR, China
| | - Marques S N Ng
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, the New Territories, Hong Kong SAR, China
| | | | - Carissa W Y Wong
- University College London Cancer Institution, University College London, London, UK
| | - Morgan Quinley
- Molecular, Cell & Development Biology, University of California, Santa Cruz, USA
| | | | - Ka Ming Chow
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, the New Territories, Hong Kong SAR, China. .,Asia-Pacific Genomic and Genetic Nursing Centre, The Chinese University of Hong Kong, Hong Kong SAR, China.
| | - Mary M Y Waye
- The Nethersole School of Nursing, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, the New Territories, Hong Kong SAR, China.,The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Hong Kong SAR, China.,Asia-Pacific Genomic and Genetic Nursing Centre, The Chinese University of Hong Kong, Hong Kong SAR, China
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5
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Kingma JS, Burgers DMT, Monpellier VM, Wiezer MJ, Blussé van Oud-Alblas HJ, Vaughns JD, Sherwin CMT, Knibbe CAJ. Oral drug dosing following bariatric surgery: General concepts and specific dosing advice. Br J Clin Pharmacol 2021; 87:4560-4576. [PMID: 33990981 PMCID: PMC9291886 DOI: 10.1111/bcp.14913] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 04/06/2021] [Accepted: 05/01/2021] [Indexed: 11/30/2022] Open
Abstract
Bariatric or weight‐loss surgery is a popular option for weight reduction. Depending on the surgical procedure, gastric changes like decreased transit time and volume and increased pH, decreased absorption surface in the small intestine, decreased exposure to bile acids and enterohepatic circulation, and decreased gastrointestinal transit time may be expected. In the years after bariatric surgery, patients will also substantially lose weight. As a result of these changes, the absorption, distribution, metabolism and/or elimination of drugs may be altered. The purpose of this article is to report the general influence of bariatric surgery on oral drug absorption, and to provide guidance for dosing of commonly used drugs in this special population. Upon oral drug administration, the time to maximum concentration is often earlier and this concentration may be higher with less consistent effects on trough concentrations and exposure. Additionally, prescription of liquid formulations to bariatric patients is supported by some reports, even though the high sugar load of these suspensions may be of concern. Studies on extended‐release medications result in an unaltered exposure for a substantial number of drugs. Also, studies evaluating the influence of timing after surgery show dynamic absorption profiles. Although for this group specific advice can be proposed for many drugs, we conclude that there is insufficient evidence for general advice for oral drug therapy after bariatric surgery, implying that a risk assessment on a case‐by‐case basis is required for each drug.
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Affiliation(s)
- Jurjen S Kingma
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands.,Department of Clinical Pharmacy, Division of Laboratories, Pharmacy, and Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Desirée M T Burgers
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - Valerie M Monpellier
- Nederlandse Obesitas Kliniek (Dutch Obesity Clinic), Huis ter Heide, The Netherlands
| | - Marinus J Wiezer
- Department of Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands
| | | | - Janelle D Vaughns
- Department of Anesthesia and Pain Medicine, Children's National Health System, Washington, DC, USA.,Division of Clinical Pharmacology, Children's National Health System, Washington, DC, USA
| | - Catherine M T Sherwin
- Department of Pediatrics, Wright State University Boonshoft School of Medicine, Dayton Children's Hospital, Dayton, Ohio, USA
| | - Catherijne A J Knibbe
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, The Netherlands.,Division of Systems Biomedicine & Pharmacology, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
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6
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Groenland SL, van Nuland M, Verheijen RB, Schellens JHM, Beijnen JH, Huitema ADR, Steeghs N. Therapeutic Drug Monitoring of Oral Anti-Hormonal Drugs in Oncology. Clin Pharmacokinet 2020; 58:299-308. [PMID: 29862467 DOI: 10.1007/s40262-018-0683-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Oral anti-hormonal drugs are essential in the treatment of breast and prostate cancer. It is well known that the interpatient variability in pharmacokinetic exposure is high for these agents and exposure-response relationships exist for many oral anti-hormonal drugs. Yet, they are still administered at fixed doses. This could lead to underdosing and thus suboptimal efficacy in some patients, while other patients could be overdosed resulting in unnecessary side effects. Therapeutic drug monitoring (TDM), individualized dosing based on measured blood concentrations of the drug, could therefore be a valid option to further optimize treatment. In this review, we provide an overview of relevant clinical pharmacokinetic and pharmacodynamic characteristics of oral anti-hormonal drugs in oncology and translate these into practical guidelines for TDM. For some agents, TDM targets are not well established yet and as a reference the median pharmacokinetic exposure could be targeted (exemestane: minimum plasma concentration (Cmin) 4.1 ng/mL and enzalutamide: Cmin 11.4 mg/L). However, for most drugs, exposure-efficacy analyses could be translated into specific targets (abiraterone: Cmin 8.4 ng/mL, anastrozole: Cmin 34.2 ng/mL, and letrozole: Cmin 85.6 ng/mL). Moreover, prospective clinical trials have shown TDM to be feasible for tamoxifen, for which the exposure-efficacy threshold of its active metabolite endoxifen is 5.97 ng/mL. Based on the available data, we therefore conclude that individualized dosing based on drug concentrations is feasible and promising for oral anti-hormonal drugs and should be developed further and implemented into clinical practice.
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Affiliation(s)
- Stefanie L Groenland
- Division of Medical Oncology, Department of Clinical Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
| | - Merel van Nuland
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek and MC Slotervaart, Amsterdam, The Netherlands
| | - Remy B Verheijen
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek and MC Slotervaart, Amsterdam, The Netherlands
| | - Jan H M Schellens
- Division of Medical Oncology, Department of Clinical Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Jos H Beijnen
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek and MC Slotervaart, Amsterdam, The Netherlands.,Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Alwin D R Huitema
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek and MC Slotervaart, Amsterdam, The Netherlands.,Department of Clinical Pharmacy, University Medical Center, Utrecht University, Utrecht, The Netherlands
| | - Neeltje Steeghs
- Division of Medical Oncology, Department of Clinical Pharmacology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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7
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Helland T, Hagen KB, Haugstøyl ME, Kvaløy JT, Lunde S, Lode K, Lind RA, Gripsrud BH, Jonsdottir K, Gjerde J, Bifulco E, Hustad S, Jonassen J, Aas T, Lende TH, Lien EA, Janssen EAM, Søiland H, Mellgren G. Drug monitoring of tamoxifen metabolites predicts vaginal dryness and verifies a low discontinuation rate from the Norwegian Prescription Database. Breast Cancer Res Treat 2019; 177:185-195. [PMID: 31144152 DOI: 10.1007/s10549-019-05294-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/22/2019] [Indexed: 11/30/2022]
Abstract
PURPOSE Tamoxifen is an important targeted endocrine therapy in breast cancer. However, side effects and early discontinuation of tamoxifen remains a barrier for obtaining the improved outcome benefits of long-term tamoxifen treatment. Biomarkers predictive of tamoxifen side effects remain unidentified. The objective of this prospective population-based study was to investigate the value of tamoxifen metabolite concentrations as biomarkers for side effects. A second objective was to assess the validity of discontinuation rates obtained through pharmacy records with the use of tamoxifen drug monitoring. METHODS Longitudinal serum samples, patient-reported outcome measures and pharmacy records from 220 breast cancer patients were obtained over a 6-year period. Serum concentrations of tamoxifen metabolites were measured by LC-MS/MS. Associations between metabolite concentrations and side effects were analyzed by logistic regression and cross table analyses. To determine the validity of pharmacy records we compared longitudinal tamoxifen concentrations to discontinuation rates obtained through the Norwegian Prescription database (NorPD). Multivariable Cox regression models were performed to identify predictors of discontinuation. RESULTS At the 2nd year of follow-up, a significant association between vaginal dryness and high concentrations of tamoxifen, Z-4'-OHtam and tam-NoX was identified. NorPD showed a tamoxifen-discontinuation rate of 17.9% at 5 years and drug monitoring demonstrated similar rates. Nausea, vaginal dryness and chemotherapy-naive status were significant risk factors for tamoxifen discontinuation. CONCLUSIONS This real-world data study suggests that measurements of tamoxifen metabolite concentrations may be predictive of vaginal dryness in breast cancer patients and verifies NorPD as a reliable source of adherence data.
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Affiliation(s)
- Thomas Helland
- Hormone Laboratory, Haukeland University Hospital, 5020, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Kari Britt Hagen
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Breast and Endocrine Surgery, Haukeland University Hospital, Bergen, Norway
| | - Martha Eimstad Haugstøyl
- Hormone Laboratory, Haukeland University Hospital, 5020, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Jan Terje Kvaløy
- Department of Mathematics and Natural Science, University of Stavanger, Stavanger, Norway
- Department of Research, Stavanger University Hospital, Stavanger, Norway
| | - Siri Lunde
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Kirsten Lode
- Department of Research, Stavanger University Hospital, Stavanger, Norway
| | - Ragna Anne Lind
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Birgitta Haga Gripsrud
- Department of Caring and Ethics, Faculty of Health Sciences, University of Stavanger, Stavanger, Norway
| | - Kristin Jonsdottir
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
- Department of Research, Stavanger University Hospital, Stavanger, Norway
| | - Jennifer Gjerde
- Hormone Laboratory, Haukeland University Hospital, 5020, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ersilia Bifulco
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Core Facility for Metabolomics, University of Bergen, Bergen, Norway
| | - Steinar Hustad
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Core Facility for Metabolomics, University of Bergen, Bergen, Norway
| | - Janne Jonassen
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Turid Aas
- Department of Breast and Endocrine Surgery, Haukeland University Hospital, Bergen, Norway
| | - Tone Hoel Lende
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Ernst Asbjørn Lien
- Hormone Laboratory, Haukeland University Hospital, 5020, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Emiel Adrianus Maria Janssen
- Department of Mathematics and Natural Science, University of Stavanger, Stavanger, Norway
- Department of Pathology, Stavanger University Hospital, Stavanger, Norway
| | - Håvard Søiland
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Department of Breast and Endocrine Surgery, Stavanger University Hospital, Stavanger, Norway
| | - Gunnar Mellgren
- Hormone Laboratory, Haukeland University Hospital, 5020, Bergen, Norway.
- Department of Clinical Science, University of Bergen, Bergen, Norway.
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8
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Lee CI, Fox P, Balakrishnar B, Balleine RL, Gao B, Provan P, Coulter S, Liddle C, Hui R, Wong M, Gurney H, Wilcken N. Tamoxifen-induced severe hot flashes and endoxifen levels: is dose reduction a safe and effective strategy? Breast 2019; 46:52-57. [PMID: 31082762 DOI: 10.1016/j.breast.2019.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 04/17/2019] [Accepted: 05/03/2019] [Indexed: 10/26/2022] Open
Abstract
OBJECTIVES Severe hot flash (HF) toxicity due to tamoxifen can compromise compliance. We previously found that HFs did not correlate with endoxifen level or CYP2D6 genotype. In this study, we reduced tamoxifen dose in patients with severe HFs to determine whether HFs were ameliorated whilst maintaining a purported therapeutic endoxifen level of >15 nM. MATERIALS AND METHODS Twenty patients with severe HFs on 20 mg TAM had CYP2D6genotype, trough level tamoxifen and metabolites measured with Loprinzi HF scores (HFS) derived before and after DR of tamoxifen to 10 mg. Other data collected included demographics, smoking, alcohol, menstrual and breast cancer history, previous chemotherapies, concurrent medications, BMI and other tamoxifen toxicities. RESULTS At the 20 mg tamoxifen dose, endoxifen levels were 25.6, 0-91.9 nM (median, range) with HFS 131, 22-1482 (median, range). Upon DR to 10 mg, median endoxifen level fell to 14.1, 0.6-71.9 nM (difference in means p = 0.11, two-tailed T test) with HFS 47, 5-864 (difference in means p = 0.24, two-tailed T test). Despite lacking statistical significance, 85% of patients reported subjective improvement of HFs with DR. After DR, the proportion of patients with endoxifen level <15 nM increased from 20% to 50%. HFS did not correlate with any other parameter. CONCLUSION DR of tamoxifen from 20 mg to 10 mg daily resulted in halving of endoxifen levels and subjective improvement of HF. While half the dose-reduced patients were below a potential therapeutic level of endoxifen, other recent studies suggest that low endoxifen levels may not indicate reduced effectiveness of tamoxifen.
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Affiliation(s)
- Clara I Lee
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Department of Medical Oncology, Bankstown-Lidcombe Hospital, Bankstown, Australia; Faculty of Medicine, University of New South Wales, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia.
| | - Peter Fox
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | | | - Rosemary L Balleine
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Westmead Institute for Medical Research, Westmead, Australia
| | - Bo Gao
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Pamela Provan
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia
| | - Sally Coulter
- Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia; Westmead Institute for Medical Research, Westmead, Australia
| | - Christopher Liddle
- Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia; Westmead Institute for Medical Research, Westmead, Australia
| | - Rina Hui
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia
| | - Mark Wong
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia
| | - Howard Gurney
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia; Macquarie University, Australia
| | - Nicholas Wilcken
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia; Faculty of Medicine and Health, The University of Sydney, Camperdown, Australia
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9
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van Nuland M, Vreman RA, Ten Ham RMT, de Vries Schultink AHM, Rosing H, Schellens JHM, Beijnen JH, Hövels AM. Cost-effectiveness of monitoring endoxifen levels in breast cancer patients adjuvantly treated with tamoxifen. Breast Cancer Res Treat 2018; 172:143-150. [PMID: 30006796 PMCID: PMC6208915 DOI: 10.1007/s10549-018-4886-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 07/10/2018] [Indexed: 01/13/2023]
Abstract
PURPOSE Breast cancer is the most common malignancy in women worldwide. Recurrence rates in breast cancer are considered to be dependent on the serum concentration of endoxifen, the active metabolite of tamoxifen. The goal of this study is to investigate the cost-effectiveness of periodically monitoring serum concentrations of endoxifen in adjuvant estrogen receptor alfa (ERα) positive breast cancer patients treated with tamoxifen in the Netherlands. METHODS A Markov model with disease-free survival (DFS), recurrent disease (RD), and death states was constructed. The benefit of drug monitoring was modeled via a difference in the fraction of patients achieving adequate serum concentrations. Robustness of results to changes in model assumptions were tested through deterministic and probabilistic sensitivity analyses. RESULTS Monitoring of endoxifen added 0.0115 quality-adjusted life-years (QALYs) and saved € 1564 per patient in the base case scenario. Deterministic sensitivity analysis demonstrated a large effect on the incremental cost-effectiveness ratio (ICER) of the differences in costs and utilities between the DFS and RD states. Probabilistic sensitivity analysis showed that the probability of cost-effectiveness at a willingness to pay of € 0 per quality-adjusted life-year (QALY) was 89.8%. CONCLUSIONS Based on this model, monitoring of endoxifen in adjuvant ERα + breast cancer patients treated with tamoxifen is likely to add QALYs and save costs from a healthcare payer perspective. We advise clinicians to consider integrating serum endoxifen concentration monitoring into standard adjuvant tamoxifen treatment of ERα + breast cancer patients.
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Affiliation(s)
- M van Nuland
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute and MC Slotervaart, Amsterdam, The Netherlands. .,Division of Pharmacology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands. .,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
| | - R A Vreman
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - R M T Ten Ham
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - A H M de Vries Schultink
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute and MC Slotervaart, Amsterdam, The Netherlands.,Division of Pharmacology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - H Rosing
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute and MC Slotervaart, Amsterdam, The Netherlands
| | - J H M Schellens
- Division of Pharmacology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.,Division of Clinical Pharmacology, Department of Medical Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - J H Beijnen
- Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute and MC Slotervaart, Amsterdam, The Netherlands.,Division of Pharmacology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - A M Hövels
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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10
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Jansen LE, Teft WA, Rose RV, Lizotte DJ, Kim RB. CYP2D6 genotype and endoxifen plasma concentration do not predict hot flash severity during tamoxifen therapy. Breast Cancer Res Treat 2018; 171:701-708. [PMID: 29980881 DOI: 10.1007/s10549-018-4876-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE Tamoxifen is frequently prescribed to prevent breast cancer recurrence. Tamoxifen is a prodrug and requires bioactivation by CYP2D6. Tamoxifen use is often limited by adverse effects including severe hot flashes. There is paucity of prospectively collected data in terms of CYP2D6 genotype and measured tamoxifen, 4-hydroxytamoxifen and endoxifen concentrations in relation to hot flash severity during tamoxifen therapy. METHODS We conducted a longitudinal prospective study of breast cancer patients on tamoxifen (n = 410). At each visit, blood samples were collected, and patients completed a standardized hot flash survey (n = 1144) that reflected hot flash severity during the 7 days prior to the visit. Plasma concentrations of tamoxifen, 4-hydroxytamoxifen, and endoxifen were measured using liquid chromatography-tandem mass spectrometry and genotyping was carried out for CYP2D6. A linear mixed-effects regression analysis assessed the association of covariates in relation to the hot flash severity score (HFSS). RESULTS Median age at first assessment was 50 years with 61.9% of patients considered peri-menopausal. Most patients (92.2%) experienced hot flash symptoms with 51.0% having low HFSS (0-4) and 7.32% experiencing HFSS > 25. Age was significantly associated with hot flash severity, with patients aged 45-59 more likely to have higher HFSS. Neither duration of tamoxifen therapy nor observed tamoxifen, endoxifen and 4-hydroxy tamoxifen plasma concentration predicted hot flash severity. Genetic variation in CYP2D6 or CYP3A4 was not predictive of hot flash severity. CONCLUSIONS Hot flash severity during tamoxifen therapy can not be accounted for by CYP2D6 genotype or observed plasma concentration of tamoxifen, 4-hydroxytamoxifen, or endoxifen.
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Affiliation(s)
- Laura E Jansen
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada
| | - Wendy A Teft
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada
| | - Rhiannon V Rose
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5K5, Canada
| | - Daniel J Lizotte
- Department of Epidemiology and Biostatistics, Western University, London, ON, N6A 5K5, Canada
| | - Richard B Kim
- Department of Medicine, Division of Clinical Pharmacology, Western University, London, ON, N6A 5K5, Canada. .,Department of Oncology, Western University, London, ON, N6A 5K5, Canada. .,Department of Medicine, LHSC-University Hospital, Room A-LL-152, 339 Windermere Road, London, ON, N6A 5A5, Canada.
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11
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Yoo TK, Jang MJ, Lee E, Moon HG, Noh DY, Han W. Endocrine Treatment-Related Symptoms and Patient Outcomes in Breast Cancer: A Meta-Analysis. J Breast Cancer 2018; 21:37-44. [PMID: 29628982 PMCID: PMC5880964 DOI: 10.4048/jbc.2018.21.1.37] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 01/08/2018] [Indexed: 11/30/2022] Open
Abstract
Purpose An association between endocrine treatment-related symptoms and breast cancer recurrence has been suggested previously; however, conflicting results have been reported. We performed a meta-analysis of published studies to clarify this relationship. Methods We systematically searched PubMed, Embase, Scopus, and the Cochrane database for studies investigating the association between endocrine treatment-related symptoms and patient survival. Random-effects meta-analysis was conducted with recurrence rate as the primary outcome. Results Out of 7,713 retrieved articles, six studies were included. In patients who received endocrine treatment, the presence of any endocrine treatment-related symptom was found to be associated with a lower recurrence rate in comparison to an absence of any symptoms (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.66-0.87). This relationship persisted in patients presenting with only vasomotor or only musculoskeletal symptoms (HR, 0.74, 95% CI, 0.63-0.87; HR, 0.69, 95% CI, 0.55-0.86, respectively). At both time-points of symptom evaluation (3 months and 12 months), patients with endocrine treatment-related symptoms had a lower recurrence rate (HR, 0.74, 95% CI, 0.66-0.84; HR, 0.79, 95% CI, 0.69-0.90, respectively). This association was also significant in pooled studies including patients with and without baseline symptoms (HR, 0.73, 95% CI, 0.54-0.99; HR, 0.76, 95% CI, 0.69-0.85, respectively). Conclusion Endocrine treatment-related symptoms are significantly predictive of lower recurrence rate in breast cancer patients, regardless of the type of symptoms, time-point of evaluation, or inclusion of baseline symptoms. These symptoms could be biomarkers for the prediction of long-term responses to endocrine treatment in patients with breast cancer.
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Affiliation(s)
- Tae-Kyung Yoo
- Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Myoung-Jin Jang
- Medical Research Collaborating Center, Seoul National University Hospital, Seoul, Korea
| | - Eunshin Lee
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.,Laboratory of Breast Cancer Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Hyeong-Gon Moon
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.,Laboratory of Breast Cancer Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Dong-Young Noh
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.,Laboratory of Breast Cancer Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Wonshik Han
- Department of Surgery, Seoul National University College of Medicine, Seoul, Korea.,Laboratory of Breast Cancer Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
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12
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Binkhorst L, Bannink M, de Bruijn P, Ruit J, Droogendijk H, van Alphen RJ, den Boer TD, Lam MH, Jager A, van Gelder T, Mathijssen RHJ. Augmentation of Endoxifen Exposure in Tamoxifen-Treated Women Following SSRI Switch. Clin Pharmacokinet 2016; 55:249-55. [PMID: 26446141 PMCID: PMC4756062 DOI: 10.1007/s40262-015-0315-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND OBJECTIVE The anti-oestrogen tamoxifen requires metabolic activation to endoxifen by cytochrome P450 (CYP) enzymes, predominantly CYP2D6. Potent CYP2D6-inhibiting antidepressants can seriously disrupt tamoxifen metabolism, probably influencing the efficacy of tamoxifen. For this reason, paroxetine and fluoxetine are recommended not to be used with tamoxifen in breast cancer patients. We investigated the effects of switching potent CYP2D6-inhibiting antidepressants to weak CYP2D6-inhibiting antidepressants on the plasma pharmacokinetics of tamoxifen. METHODS Ten breast cancer patients who were treated with tamoxifen in combination with a potent CYP2D6-inhibiting antidepressant (paroxetine or fluoxetine) for at least 4 weeks were enrolled. Under close supervision by a psychiatrist, patients were switched to treatment with escitalopram or venlafaxine (weak CYP2D6-inhibiting antidepressants). Before and after the switch, pharmacokinetic blood sampling was performed over 24 h. Pharmacokinetic parameters were estimated using noncompartmental analysis. Adverse effects were recorded during the study. RESULTS Endoxifen exposure was ~3-fold higher during escitalopram co-administration than during paroxetine or fluoxetine co-administration (median 387 nM·h [range 159-637 nM·h] versus 99.2 nM·h [range 70.0-210 nM·h]; P = 0.012; Wilcoxon signed-rank test). The ratio of endoxifen to N-desmethyltamoxifen and the ratio of 4-hydroxytamoxifen to tamoxifen increased by 3.3- and ~1.5-fold, reflecting increased CYP2D6 activity. Antidepressant switching did not result in psychiatric problems or antidepressant-related adverse effects. CONCLUSION In this study, switching to the weak CYP2D6 inhibitor escitalopram was safe and feasible and resulted in clinically relevant rises in endoxifen concentrations. We therefore advise switching paroxetine and fluoxetine to escitalopram in patients using tamoxifen. However, switching should always be weighed in individual patients.
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Affiliation(s)
- Lisette Binkhorst
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands. .,Department of Hospital Pharmacy, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
| | - Marjolein Bannink
- Department of Psychiatry, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Peter de Bruijn
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands
| | - Jan Ruit
- Department of Internal Medicine, Vlietland Hospital, Schiedam, The Netherlands
| | - Helga Droogendijk
- Department of Internal Medicine, Franciscus Hospital, Roosendaal, The Netherlands
| | - Robbert J van Alphen
- Department of Internal Medicine, Elisabeth TweeSteden Hospital, Tilburg, The Netherlands
| | - Tilly D den Boer
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands
| | - Mei Ho Lam
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands
| | - Agnes Jager
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands
| | - Teun van Gelder
- Department of Hospital Pharmacy, Erasmus MC University Medical Center, Rotterdam, The Netherlands.,Department of Internal Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Ron H J Mathijssen
- Department of Medical Oncology, Erasmus MC Cancer Institute, 's Gravendijkwal 230, 3015 CE, Rotterdam, The Netherlands
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13
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Fox P, Balleine RL, Lee C, Gao B, Balakrishnar B, Menzies AM, Yeap SH, Ali SS, Gebski V, Provan P, Coulter S, Liddle C, Hui R, Kefford R, Lynch J, Wong M, Wilcken N, Gurney H. Dose Escalation of Tamoxifen in Patients with Low Endoxifen Level: Evidence for Therapeutic Drug Monitoring-The TADE Study. Clin Cancer Res 2016; 22:3164-71. [PMID: 26847054 DOI: 10.1158/1078-0432.ccr-15-1470] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/17/2016] [Indexed: 11/16/2022]
Abstract
PURPOSE Endoxifen is the major mediator of tamoxifen effect and endoxifen levels <15 nmol/L may be associated with increased risk of breast cancer recurrence. We increased tamoxifen dose in breast cancer patients with low endoxifen levels and assessed the influence of various parameters on reaching 15 nmol/L and 30 nmol/L endoxifen levels. EXPERIMENTAL DESIGN Tamoxifen dose was increased in those with endoxifen levels below 30 nmol/L. Toxicity, including hot flash score, was measured. CYP2D6 metabolizer status was classified as ultra-rapid (UM), extensive (EM), intermediate (IM), or poor (PM) based genotype of somatic DNA. RESULTS Dosage was escalated in 68 of 122 participants. On 20 mg tamoxifen, 24% had endoxifen levels below 15 nmol/L and this reduced to 6% following dose escalation. In over 50% of cases, there was no identified cause for low endoxifen. Low baseline endoxifen level, and not CYP2D6 metabolizer status, independently predicted reaching threshold targets for both the 15 nmol/L and 30 nmol/L targets (P = 0.04 and 0.003 respectively). The 15 nmol/L target was reached in all UM/EM and IM patients, 63% of PM patients, and 58% of those with baseline endoxifen of <10 nmol/L. There was no correlation between hot flash score and genotype or any tamoxifen metabolite level including endoxifen (R = 0.07). CONCLUSIONS Low endoxifen on standard dose tamoxifen was the only independent predictor of failure to achieve potentially therapeutic levels. Trials examining tamoxifen dose escalation and breast cancer outcome should be guided by endoxifen levels alone, without reference to CYP2D6 genotype or presence of hot flashes. Clin Cancer Res; 22(13); 3164-71. ©2016 AACRSee related commentary by Hertz and Rae, p. 3121.
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Affiliation(s)
- Peter Fox
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Rosemary L Balleine
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Pathology West, Institute for Clinical Pathology and Medical Research, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Westmead Millennium Institute for Medical Research, Westmead, Australia
| | - Clara Lee
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Bo Gao
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | | | | | - Shang Heng Yeap
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | | | - Val Gebski
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia
| | - Pamela Provan
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Sally Coulter
- Westmead Millennium Institute for Medical Research, Westmead, Australia
| | - Christopher Liddle
- Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Westmead Millennium Institute for Medical Research, Westmead, Australia. Storr Liver Centre, Westmead Hospital, Westmead, Australia
| | - Rina Hui
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Richard Kefford
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | | | - Mark Wong
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Nicholas Wilcken
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia
| | - Howard Gurney
- Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia. Sydney Medical School - Westmead, University of Sydney, Sydney, Australia. Faculty of Medicine and Health Sciences, Macquarie University, Sydney Australia.
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14
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Binkhorst L, Mathijssen RH, Jager A, van Gelder T. Individualization of tamoxifen therapy: Much more than just CYP2D6 genotyping. Cancer Treat Rev 2015; 41:289-99. [DOI: 10.1016/j.ctrv.2015.01.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 12/30/2014] [Accepted: 01/07/2015] [Indexed: 12/12/2022]
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15
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Baxter SD, Teft WA, Choi YH, Winquist E, Kim RB. Tamoxifen-associated hot flash severity is inversely correlated with endoxifen concentration and CYP3A4*22. Breast Cancer Res Treat 2014; 145:419-28. [DOI: 10.1007/s10549-014-2963-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 04/08/2014] [Indexed: 12/14/2022]
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