Effect of Ospemifene on the Pharmacokinetics of the Co-Administered Drug

Warfarin

Ospemifene 60 mg was given after a light breakfast (two slices of bread with ham and cheese and juice) once daily for 12 days in sixteen postmenopausal women who were determined to be rapid metabolizers of CYP2C9 (CYP2C9*1/*1 or CYP2C9*1/*2). On Day 8, a single dose of warfarin 10 mg and vitamin K 10 mg were administered one hour after a light breakfast. The geometric mean ratio (90% CI) for S-warfarin with and without ospemifene for Cmax and AUC0-inf were 0.97 (0.92-1.02) and 0.96 (0.91-1.02), respectively. Multiple doses of ospemifene did not significantly affect the pharmacokinetics of a single dose of warfarin. No study was conducted with multiple doses of warfarin.

Omeprazole

Ospemifene 60 mg was administered once daily for 7 days after a light meal in the late afternoon in fourteen postmenopausal women. On Day 8 after an overnight fast, a single 20 mg dose of omeprazole was administered in the morning of at least 10 hrs; ospemifene was not given on Day 8. The geometric mean ratios for the metabolic index (omeprazole/5-hydroxyomeprazole) at the concentration at the 3 hr time point and for AUC0-8hr was 0.97 with and without ospemifene. It is unclear if ospemifene will affect the pharmacokinetics of drugs metabolized by CYP2C19 due to the significant time gap between ospemifene and omeprazole administration.

Bupropion

Ospemifene 60 mg was administered once daily for seven consecutive days after the evening meal in sixteen postmenopausal women (not homozygous for CYP2B6*6). On the Day 8 after overnight fast, a single 150 mg dose of sustained release bupropion was administered in morning under fasted condition. The geometric mean ratio (90% CI) for bupropion with and without ospemifene for Cmax and AUC0-inf were 0.82 (0.75-0.91) and 0.81 (0.77-0.86), respectively. The geometric mean ratio (90% CI) for hydroxybupropion, an active metabolite formed via CYP2B6, with and without ospemifene for Cmax and AUC0-inf were 1.16 (1.09-1.24) and 0.98 (0.92-1.04), respectively.
13. NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
Carcinogenesis

In a 2-year carcinogenicity study in female mice, ospemifene administration of 100, 400 or 1500 mg/kg/day was well tolerated. No eva luation for carcinogenicity was conducted in male mice. There was significant increase in adrenal subcapsular cell adenomas at 4 and 5 times the human exposure based on AUC, and adrenal cortical tumors at 5 times the human exposure. In the ovary, an increase in sex cord/stromal tumors, tubulostromal tumors, granulosa cell tumors, and luteomas were also seen. These findings occurred at doses 2 to 5 times the human exposure based on AUC, and are probably related to estrogenic/antiestrogenic effect of ospemifene in mice.

In a 2-year carcinogenicity study in rats, ospemifene administration of 10, 50, or 300 mg/kg/day was well tolerated. A significant increase in thymomas was recorded for males and thymomas for females at all ospemifene dose levels, or 0.3 to 1.2 times the human exposure based on AUC. In the liver, an increase in hepatocellular tumors were recorded at for females at al