New CPIC Guideline: CYP2D6 and tamoxifen

The CPIC Guideline for tamoxifen and CYP2D6 is now published in Clinical Pharmacology and Therapeutics. The accepted article can be viewed on the PharmGKB page for tamoxifen, and the CPIC website.

Tamoxifen is a selective estrogen receptor modulator (SERM) and is utilized in breast cancer treatment. Tamoxifen is extensively metabolized, in part by CYP2D6. Patients with certain CYP2D6 genetic polymorphisms and patients who receive strong CYP2D6 inhibitors exhibit lower endoxifen concentrations and a higher risk of disease recurrence in some studies of tamoxifen adjuvant therapy of early breast cancer.

The CPIC guideline and supplement summarize evidence from the literature and provide therapeutic recommendations for tamoxifen based on CYP2D6 genotype.

For further details see the guidelines and supplement on CPIC, or on the pages for tamoxifen on PharmGKB.

Researchers interested in a highly curated genotype-phenotype data set for women treated with tamoxifen, please see the International Tamoxifen Pharmacogenetics Consortia (ITPC) paper published in Clin Pharmacol Ther (2014; PMID 24060820) with the associated data set at PharmGKB.