1. Exemestane may be less detrimental than letrozole to bone health in women homozygous for the UGT2B17*2 gene deletion
- Author
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Bryana J. Gregory, Jingyue Xi, Kelley M. Kidwell, Daniel F. Hayes, Ana Maria Storniolo, Daniel L. Hertz, Landry K. Kamdem, Vered Stearns, James M. Rae, Brandi L. Clark, N. Lynn Henry, and Christina L. Gersch
- Subjects
musculoskeletal diseases ,0301 basic medicine ,Oncology ,Cancer Research ,medicine.medical_specialty ,Genotype ,medicine.drug_class ,Breast Neoplasms ,Article ,Bone and Bones ,Bone remodeling ,Minor Histocompatibility Antigens ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Breast cancer ,Exemestane ,Bone Density ,Internal medicine ,medicine ,Humans ,Glucuronosyltransferase ,Genetic Association Studies ,Bone mineral ,Aromatase inhibitor ,Aromatase Inhibitors ,business.industry ,Letrozole ,Middle Aged ,medicine.disease ,Androstadienes ,Postmenopause ,Tamoxifen ,030104 developmental biology ,chemistry ,Pharmacogenetics ,Hormone receptor ,030220 oncology & carcinogenesis ,Female ,Bone Remodeling ,business ,Gene Deletion ,medicine.drug - Abstract
PURPOSE: UGT2B17 gene deletion (UGT2B17*2) has been reported to affect bone health as well as the pharmacokinetics of aromatase inhibitor (AI) drugs such as exemestane. The goal of this study was to assess associations between UGT2B17 gene deletion and bone health prior to and after 24 months of AI treatment in postmenopausal women with hormone receptor positive (HR+) breast cancer. METHODS: Bone health in women with HR+ breast cancer enrolled on the prospective randomized Exemestane and Letrozole Pharmacogenetics (ELPh) trial was determined by measuring bone turnover markers (BTM) and bone mineral density (BMD) pre-treatment and after 3 (BTM) and 24 (BMD) months of treatment with either the steroidal AI exemestane or the nonsteroidal AI letrozole. DNA samples were genotyped for UGT2B17*2. RESULTS: Of the 455 subjects included in the analyses, 244 (53.6%) carried at least one copy of UGT2B17*2. UGT2B17*2 was associated with lower pre-treatment BMD at the hip (P = 0.01) and spine (P = 0.0076). Letrozole treatment was associated with a greater decrease in BMD of the hip (P = 0.03) and spine (P = 0.03) than exemestane. UGT2B17 genotype was not associated with changes in BMD from 24 months of AI treatment, though in UGT2B17*2 homozygous patients, there was a trend toward greater decreases in BMD of the spine from treatment with letrozole compared with exemestane (P = 0.05). CONCLUSION: UGT2B17*2 may be associated with lower baseline BMD in women with HR+ breast cancer. Exemestane is less detrimental to bone health than letrozole in postmenopausal women treated with AI, and this effect may be confined to patients carrying UGT2B17*2, though this finding requires independent validation.
- Published
- 2019
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