From Genotype to Therapeutic Monitoring: Enhancing Tamoxifen Efficacy in Breast Cancer Treatment.

ABSTRACT: Endoxifen is the most active metabolite of tamoxifen and plays a central role in its therapeutic efficacy. However, significant interindividual variability in endoxifen plasma concentrations, driven by both genetic and non-genetic factors, may result in subtherapeutic exposure for a substantial subset of patients. This study evaluated the influence of CYP2D6 phenotype and age on endoxifen steady-state concentrations and explored the clinical utility of therapeutic drug monitoring (TDM) to guide tamoxifen therapy. A total of 63 breast cancer patients receiving tamoxifen 20 mg daily for at least 3 months were enrolled. Patients were genotyped for CYP2D6 using TaqMan assays and classified as normal metabolizers (NMs, n = 49), intermediate metabolizers (IMs, n = 13), or ultrarapid metabolizers

SUBMITTER: Mendes Batista AF 

PROVIDER: S-EPMC12649294 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature