Dextromethorphan phenotyping as a test for prediction of tamoxifen (TAM) activation in breast cancer patients receiving adjuvant hormone therapy.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13019-e13019
Author(s):  
Milena Gusella ◽  
Laura Bertolaso ◽  
Felice Pasini ◽  
Yasmina Modena ◽  
Antonio Bononi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Cancer Patients ◽  
Plasma Levels ◽  
Linear Regression Analysis ◽  
Plasma Concentrations ◽  
Breast Cancer Patients ◽  
Active Metabolites ◽  
Adjuvant Hormone Therapy ◽  
State Plasma

e13019 Background: TAM is mainly metabolized by CYP2D6 to form its most active metabolites, 4hydroxy-tamoxifen (4OH-T) and endoxifen (END). Because of its long half-life, steady state is reached after around 4 months of continuous intake. The wide variable inter-patient activity of CYP2D6 might influence drug efficacy. A multi-institutional study in north Italy is evaluating the relationship between END levels and outcome. As a part of it, we investigated the role of dextromethorphan (DM), a probe drug for CYP2D6 enzymatic activity, as a potential phenotyping test for TAM activation. Methods: Twenty-nine breast cancer patients (75% postmenopausal) on adjuvant TAM therapy (20 mg/die) were investigated. They received a single dose (15 mg) of oral DM before starting TAM and their urines were collected over the10 following hours. Simultaneous quantitative determination of DM and its metabolite dextrorphan (DO) was performed in urines to estimate their log transformed metabolic ratio (LMR=logDM/DO). After 4 months a blood sample was collected to characterize TAM exposure at steady state; plasma levels of TAM, END, 4OH-T and the non active END precursor N-desmethyltamoxifen (NDT) were quantified by HPLC. Linear regression analysis and t test were performed for correlating LMR and drug plasma levels. Results: LMR varied between -2.15 and 0.90 (median: -1.37) while steady state plasma levels of END varied between 1.9 and 15.0 ng/ml (median: 4.36) and 4OH-T between 0.9 to 3.1 ng/ml (median:1.72). A significant correlation (r = 0.56; p= 0.0013) was found between LMR and END plasma concentrations. The patients with high LMR (> median value), compared to patients with low LMR, had lower END (3.7 vs 7.5 ng/ml, p=0.0003), lower 4OH-T (1.6 vs 2.1 ng/ml, p=0.04) and, accordingly, higher NDT (291.2 vs 198.2 ng/ml, p=0.025). Conclusions: DM/DO urine ratio obtained before starting therapy correlates with TAM biotransformation activity and can predict steady state active metabolites exposure in individual patients. This phenotyping test is fast, simple and unexpensive and could contribute to the personalization of adjuvant breast cancer treatment. Funded by Regione Veneto.

CYP2D6 genotypes in association with steady state plasma concentrations of active metabolites of tamoxifen in patients with breast cancer

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 634-634 ◽  
Author(s):  
H. Lim ◽  
H. Lee ◽  
K. Lee ◽  
E. Lee ◽  
I. Jang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Plasma Concentrations ◽  
Cancer Center ◽  
Cyp2d6 Genotype ◽  
Active Metabolites ◽  
Fluorescence Detector ◽  
Wilcoxon Rank Sum Test ◽  
Center Hospital ◽  
State Plasma

634 Background: Tamoxifen is a prodrug that is metabolized to active metabolites, Z-4-hydroxy-N-desmethyltamoxifen (BX) and Z-4-hydroxy-tamoxifen (4OH) where CYP2D6 plays a major role in the conversion. Genetic polymorphisms of CYP2D6 by ethnicities are well known with CYP2D6*10 in Asians (up to 50% in Koreans), and CYP2D6 *2 and *4 in American Whites as major variant alleles. We analyzed the steady state plasma concentrations of tamoxifen and its metabolites in patients (pts) with breast cancer to evaluate their associations with various CYP2D6 genotypes. Methods: Blood samples were collected from 219 pts on tamoxifen, 20 mg daily as adjuvant therapy for more than 3 months at National Cancer Center, Korea. Plasma tamoxifen, N-desmethyltamoxifen, BX, 4OH were measured by validated HPLC with fluorescence detector, and analyzed according to CYP2D6 genotype groups by Wilcoxon rank sum test. CYP2D6*10, CYP2D6*5 and CYP2D6*2×2 were identified by PCR-RFLP methods, and the rests were classified as CYP2D6*1 (wild type). This study was approved by IRB at National Cancer Center Hospital (NCCNHS04–033) and conducted after informed consent obtained by the patients. Results: Thus far, we measured plasma concentration of tamoxifen and its metabolites for 158 pts among 198 pts genotyped. 59 pts (29.8%) carried CYP2D6*1/*1, 84 pts (42.4%) *1/*10 and 49 pts (24.7%) *10/*10. Other types were CYP2D6*1/*5 (8.6%), *5/*5 (1.0%), *1/*2×2 (2.5%). Pts with CYP2D6 *10/*10 (n=40) demonstrated significantly lower steady state plasma concentrations of BX and 4OH than those with other genotypes (n=118) (BX: 7.9 vs.19.2. ng/ml [95 % CI; 5.5–10.4 vs. 15.8–22.7 ng/ml] p<0.0001; 4OH: 1.5 vs. 2.8 ng/ml [95 % CI; 1.1–2.0 vs. 2.3–3.3 ng/ml] p<0.0001), whereas there were no differences with *1/*10 (n=64) vs. without *10 allele (n=54) (BX: 20.6 vs. 18.1 ng/ml; 4OH: 2.9 vs. 2.7 ng/ml). Basically no significant differences in BX/4OH or other compounds by various CYP2D6*2 ×2 and *5 alleles were observed. Conclusions: The steady state plasma concentrations of BX and 4OH were significantly low with CYP2D6 *10/*10 genotype, and their clinical implications need to be explored.(Supported by a grant NCC-0410590). No significant financial relationships to disclose.

scholarly journals Predicting steady‐state endoxifen plasma concentrations in breast cancer patients by CYP2D6 genotyping or phenotyping. Which approach is more reliable?

2020 ◽  
Vol 8 (5) ◽  
Author(s):  
Milena Gusella ◽  
Felice Pasini ◽  
Barbara Corso ◽  
Laura Bertolaso ◽  
Giovanni De Rosa ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Cancer Patients ◽  
Plasma Concentrations ◽  
Breast Cancer Patients

Clinical Implications of CYP2D6 Genotypes Predictive of Tamoxifen Pharmacokinetics in Metastatic Breast Cancer

2007 ◽  
Vol 25 (25) ◽  
pp. 3837-3845 ◽  
Author(s):  
Hyeong-Seok Lim ◽  
Han Ju Lee ◽  
Keun Seok Lee ◽  
Eun Sook Lee ◽  
In-Jin Jang ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Steady State ◽  
Clinical Outcome ◽  
Plasma Concentrations ◽  
Metastatic Breast ◽  
Pregnane X Receptor ◽  
Cyp2d6 Genotype ◽  
Breast Cancer Patients ◽  
State Plasma

Purpose The CYP3A and CYP2D6 enzymes play a major role in converting tamoxifen to its active metabolites. CYP3A is a highly inducible enzyme, regulated mainly by pregnane X receptor (PXR). This study assessed the association between genetic polymorphisms of CYP2D6 and PXR, and tamoxifen pharmacokinetics (PK) and clinical outcomes in patients with breast cancer. Patients and Methods Plasma concentrations of tamoxifen and its metabolites were measured. Common alleles of CYP2D6 and PXR were identified in 202 patients treated with tamoxifen 20 mg daily for more than 8 weeks. Twelve of the 202 patients and an additional nine patients with metastatic breast cancer receiving tamoxifen were assessed for clinical outcome in correlation with genotypes. Results Patients carrying CYP2D6*10/*10 (n = 49) demonstrated significantly lower steady-state plasma concentrations of 4-hydroxy-N-desmethyltamoxifen and 4-hydroxytamoxifen than did those with other genotypes (n = 153; 4-hydroxy-N-desmethyltamoxifen: 7.9 v 18.9 ng/mL, P < .0001; 4-hydroxytamoxifen: 1.5 v 2.6 ng/mL, P < .0001), whereas no difference by PXR genotypes was found. CYP2D6*10/*10 was significantly more frequent among nonresponders with MBC (100% v 50%, P = .0186). In Cox proportional hazard analysis, CYP2D6 genotype and number of disease sites were significant factors affecting time to progression (TTP). The median TTP for patients receiving tamoxifen was shorter in those carrying CYP2D6*10/*10 than for others (5.0 v 21.8 months, P = .0032) Conclusion CYP2D6*10/*10 is associated with lower steady-state plasma concentrations of active tamoxifen metabolites, which could possibly influence the clinical outcome by tamoxifen in Asian breast cancer patients.

scholarly journals Plasma levels of VEGF-A, VEGF B, and VEGFR-1 and applicability of these parameters as tumor markers in diagnosis of breast cancer

2018 ◽  
Author(s):  
Monika Zajkowska ◽  
Emilia Lubowicka ◽  
Paweł Malinowski ◽  
Maciej Szmitkowski ◽  
Sławomir Ławicki
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Predictive Value ◽  
Plasma Levels ◽  
Plasma Concentrations ◽  
Control Group ◽  
Breast Cancer Patients ◽  
Significant Difference ◽  
Vegf Family Members ◽  
Test Result

The VEGF family members are important factors in promoting angiogenesis and lymphangiogenesis in malignant processes. The aim of this study was to investigate plasma concentrations of VEGF-A, VEGF-B and their soluble VEGFR-1 receptor and their diagnostic utility and potency as compared to CA 15-3 in breast cancer patients and in relation to the control group. The study included 120 breast cancer patients and 60 control patients. Plasma levels of tested parameters were determined with ELISA and CA 15-3 levels were determined with CMIA. Concentrations of all tested parameters in breast cancer patients showed statistically significant difference when compared to the control groups (benign breast tumor patients and/or healthy women). VEGF-B showed the highest values of sensitivity (Sn) and predictive value of a negative test result (NPV) in total BC group (90% and 66.7%, respectively) and, more importantly, in stages I–II of BC (SE: 86.8%; 92.7%, NPV: 82.8%; 88.9%, respectively). Among all parameters tested, VEGF-A showed the highest specificity (Sf) (76.7%) and predictive value of a positive test result (PPV) (84.8%), yet they were lower than for CA 15-3. VEGF-A was also the best parameter that had statistically significant Area Under Curve (AUC) in stages I (0.678) and II (0.768). In the whole group of BC patients all parameters tested showed statistically significant AUC, but the maximum range was obtained for the combination of VEGF-A and CA 15-3 (0.817). The combined analysis of the studied parameters and CA 15-3 resulted in an increase in sensitivity and AUC values, which provides hope for developing a new panel of biomarkers that may be used in BC diagnosis in the future.

Prediction of individual tamoxifen activation in breast cancer patients.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. e13514-e13514
Author(s):  
Milena Gusella ◽  
Laura Bertolaso ◽  
Anna Paola Fraccon ◽  
Carmen Barile ◽  
Anna Rizzi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Cancer Patients ◽  
Plasma Levels ◽  
Metabolic Ratio ◽  
Tamoxifen Treatment ◽  
Cyp2d6 Genotype ◽  
Predictive Equation ◽  
Breast Cancer Patients ◽  
Cyp2d6 Activity

e13514 Background: Endoxifen (EN), the main active metabolite of tamoxifen (T), reaches steady state (SS) plasma levels after about 4 months of administration. It derives principally by cytochrome CYP2D6 activity, which is highly variable among patients. In order to predict individual SS EN exposure, three different approaches were investigated. Methods: Before starting T administration, 73 breast cancer patients (median age: 59 yrs, range: 30-89) were characterized by means of: 1) a phenotyping test of CYP2D6 activity, based on the urinary metabolic ratio of dextromethorphan/dextrorphan (log transformed, LMR). 2) CYP2D6 genotyping (alleles *1, *3, *4, *5, *6, *9, *10, *41), to classify patients in 3 functional groups: Extensive (EM), Intermediate (IM) and Poor (PM) Metabolizers. After starting T treatment (20mg/day), EN plasma levels were measured after 1 month (1M EN, pre- steady state) and 4 months of therapy (SS EN). ANOVA, paired and unpaired T test and linear regressions were performed to analyze associations between LMR, CYP2D6 genotype, 1M EN and SS EN. Multivariate linear regression was used to create a predictive equation; its mean prediction and absolute errors (MPE% and MAE%) and the positive and negative predictive values (PPV% and NPV%, according to median SS EN) were calculated. Results: SS EN plasma levels varied between 2.4 and 39.2 (median: 8.7) ng/ml. LMR (median: -1.6; range: -3.1- +1.2) showed a significant linear correlation with SS EN (r=-0.59; p<0.0001). CYP2D6 genotypes (EM=35.6%; IM=50.7%; PM=13.7%) were significantly associated with SS EN (ANOVA, p<0.0001). First month EN plasma levels (median: 5.9 ng/mL; range:1.2-27 ng/ml) were significantly lower than (p<0.0001), and correlated (r=0.87; p<0.0001) with, SS EN. Multiple regression analysis including age, LMR, CYP2D6 genotypes and 1M EN gave the following predictive equation: SS EN= 0.055-1.53 x LMR + 1.11 x 1M EN; (r=0.88; p<0.0001). MPE was 4.1% and MAE was 30%; PPV was 88.5% and NPV was 84.6%. Conclusions: Individual EN exposition at steady state can be reliably predicted by measuring baseline CYP2D6 activity, through the log (dextromethorphan/dextrorphan) metabolic ratio, and EN plasma concentration after 1 month of tamoxifen treatment. Funded by Regione Veneto. Clinical trial information: 532.

scholarly journals Clinical CYP2D6 Genotyping to Personalize Adjuvant Tamoxifen Treatment in ER-Positive Breast Cancer Patients: Current Status of a Controversy

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 771
Author(s):  
Tessa A. M. Mulder ◽  
Mirjam de With ◽  
Marzia del Re ◽  
Romano Danesi ◽  
Ron H. J. Mathijssen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Clinical Outcome ◽  
Cancer Patients ◽  
Plasma Concentrations ◽  
Tamoxifen Treatment ◽  
Current Status ◽  
Endocrine Treatment ◽  
Breast Cancer Patients ◽  
Er Positive ◽  
Positive Breast Cancer

Tamoxifen is a major option for adjuvant endocrine treatment in estrogen receptor (ER) positive breast cancer patients. The conversion of the prodrug tamoxifen into the most active metabolite endoxifen is mainly catalyzed by the enzyme cytochrome P450 2D6 (CYP2D6). Genetic variation in the CYP2D6 gene leads to altered enzyme activity, which influences endoxifen formation and thereby potentially therapy outcome. The association between genetically compromised CYP2D6 activity and low endoxifen plasma concentrations is generally accepted, and it was shown that tamoxifen dose increments in compromised patients resulted in higher endoxifen concentrations. However, the correlation between CYP2D6 genotype and clinical outcome is still under debate. This has led to genotype-based tamoxifen dosing recommendations by the Clinical Pharmacogenetic Implementation Consortium (CPIC) in 2018, whereas in 2019, the European Society of Medical Oncology (ESMO) discouraged the use of CYP2D6 genotyping in clinical practice for tamoxifen therapy. This paper describes the latest developments on CYP2D6 genotyping in relation to endoxifen plasma concentrations and tamoxifen-related clinical outcome. Therefore, we focused on Pharmacogenetic publications from 2018 (CPIC publication) to 2021 in order to shed a light on the current status of this debate.

scholarly journals Obesity Alters Endoxifen Plasma Levels in Young Breast Cancer Patients: A Pharmacometric Simulation Approach

2020 ◽  
Vol 108 (3) ◽  
pp. 661-670 ◽  
Author(s):  
Anna Mueller‐Schoell ◽  
Lena Klopp‐Schulze ◽  
Werner Schroth ◽  
Thomas Mürdter ◽  
Robin Michelet ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Patients ◽  
Plasma Levels ◽  
Simulation Approach ◽  
Breast Cancer Patients ◽  
Young Breast Cancer

scholarly journals 205P Influence of green tea consumption on endoxifen steady-state concentration in breast cancer patients treated with tamoxifen

2020 ◽  
Vol 31 ◽  
pp. S324
Author(s):  
L. Braal ◽  
K.G.A.M. Hussaarts ◽  
L. Seuren ◽  
E. Oomen-de Hoop ◽  
P. de Bruijn ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Steady State ◽  
Cancer Patients ◽  
Green Tea ◽  
Tea Consumption ◽  
Breast Cancer Patients ◽  
Steady State Concentration ◽  
State Concentration
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