Assessment of the Effects of Age and Renal Function on Pharmacokinetics of Bazedoxifene in Postmenopausal Women

Bazedoxifene (BZA), a chemically distinct selective estrogen receptor modulator, has demonstrated efficacy and long‐term safety in phase 3 placebo‐controlled studies for prevention and treatment of osteoporosis. Here, we assessed the potential effects of age and renal function on BZA pharmacokinetics in healthy postmenopausal women (aged 55–84 years; CLcr, 32‐109 mL/min). This was an open‐label, single‐dose, parallel, nonrandomized inpatient study conducted in healthy postmenopausal women and postmenopausal women with impaired renal function. Each subject received a single oral dose of BZA in a 20‐mg tablet. Twenty‐six subjects were enrolled: 8 in each of 3 age groups (55–64 years, 65–74 years, ≥75 years) and 2 (aged 71 and 75 years) with mild renal impairment; all subjects received treatment and completed the study. Age‐related changes in pharmacokinetics were apparent. Although the correlation was modest ( R 2 = 0.28), BZA CL/F decreased steadily with age, such that the oldest group (>75 years) had a mean CL/F 60% less than the youngest group (55–64 years). Over the observed range of CLcr, there was a weak positive correlation ( R 2 = 0.19) between BZA CL/F and CLcr.