Endoxifen levels and metabolic phenotype-associated factors in Mexican Mestizo patients under tamoxifen treatment

• Published in: Pharmacogenomics Vol. 21; no. 13; pp. 929 - 943
• Main Authors: Jorge-Aarón, Rangel-Méndez, Rodrigo, Rubi-Castellanos, Esther, Moo-Puc Rosa
• Format: Journal Article
• Language: English
• Published: London Future Medicine Ltd 01.08.2020
• Subjects: Breast cancer; Cancer therapies; CYP2D6 protein; Cytochrome P450; Deoxyribonucleic acid; DNA; endoxifen; Genotype & phenotype; Haplotypes; Hot flash; metabolic phenotype; Metabolism; Metabolites; Mexican Mestizos; Patients; Phenotypes; Tamoxifen; United States > US; Mexico
• ISSN: 1462-2416; 1744-8042
• DOI: 10.2217/pgs-2020-0061

To evaluate plasma endoxifen levels and metabolic phenotype-associated factors in Mexican Mestizo patients under tamoxifen treatment. A total of 138 breast cancer patients under tamoxifen treatment were cross-sectionally evaluated and side effects (SE) were recorded. genetic phenotypes (GP) and metabolic phenotypes (MP) were assessed (metabolic poor [mPM], intermediate [mIM], normal [mNM], and ultrarapid [mUM] metabolizer). Associations were tested in uni-multivariate models for endoxifen >5.9 ng/ml and for mNM + mUM MP. The main SE was hot flashes (62%). Distribution of the  MP was 4.3% mPM; 14.5% mIM; 75.4% mNM; and 5.8% mUM. Endoxifen >5.9 ng/ml was partially associated with SE (p = 0.06); the mNM + mUM MP was associated with treatment time (p = 0.03). The endoxifen-associated factors in Mexican Mestizo patients remain inconclusive, although treatment time was associated with MP.