The effects of synthetic conjugated estrogens, a (cenestin) on trabecular bone structure and strength in the ovariectomized rat model.

This study evaluated the effect of Cenestin, a synthetic conjugated estrogens product, on the maintenance of trabecular bone microarchitecture, bone strength, and of bone turnover in the ovariectomized (ovx) rat model. Two doses of Cenestin were chosen in an attempt to approximate the equivalent human oral doses of 0.3 mg and 0.625 mg. Forty-nine 6-month-old retired female breeder Sprague-Dawley rats were randomly assigned to one of four groups: (1) sham-operated + vehicle; (2) ovx + vehicle; (3) ovx + day 1 post-ovariectomy Cenestin (8.12 mg/kg); (4) ovx + day 1 post-ovariectomy Cenestin (16.24 mg/kg) for 8 weeks. Trabecular structure of the right proximal tibia of each rat was imaged noninvasively by microCT. A compression test to induce a tibial plateau fracture was performed to determine the mechanical properties of the proximal tibia. Urine was collected on days 0, 14, 28, 42 and 56 and serum on days 0, 28 and 56 to assess biochemical markers of bone turnover including deoxypyridinoline crosslinks and osteocalcin. Both biochemical markers of bone turnover were analyzed by ELISA. Trabecular bone mass, structure, and connectivity density in the Cenestin-treated groups did not differ statistically ( p>0.05) from those of the sham-operated + vehicle-treated rats, but all were significantly higher ( p<0.05) than in the ovx + vehicle-treated rats. Structure Model Index, a measure of trabecular plate morphometry, in Cenestin-treated rats maintained a more equal mix of plate- and rod-like structures similar to the sham group, whereas the ovx group had predominantly rod-like trabeculae. Fracture load in the Cenestin (16.24 mg/kg) treated group was 31% ( p<0.01) higher than in the sham + vehicle-treated group and 61% ( p<0.05) higher than in the ovx + vehicle-treated group. Both the sham-operated + vehicle-treated and Cenestin-treated groups showed significantly lower urinary deoxypyridinoline crosslink excretion at all timepoints and serum osteocalcin at day 56 compared with the ovx + vehicle-treated group. In summary, Cenestin maintained trabecular bone microarchitecture and strength in an ovariectomized rat model of estrogen deficiency.

Evaluation of single- and multiple-dose pharmacokinetics of synthetic conjugated estrogens, A (Cenestin) tablets: a slow-release estrogen replacement product.

A multiple-dose, placebo-controlled, randomized pharmacokinetic study was performed in 15 early (i.e., 1-3 years) postmenopausal women to evaluate the single and steady-state pharmacokinetics of 0.625 mg Cenestin (Synthetic Conjugated Estrogens, A) tablets, administered once daily for 90 days. Plasma concentration-time profiles for both total (conjugated and unconjugated) estrone and equilin, two major estrogens in Cenestin, were nearly superimposable between Day 1 (single dose) and Day 90 (multiple dose), indicating equivalent drug exposure from one dose to the next. For total estrone, the mean estimates of Cmax and AUC0-24 were 2.5 ng/ml and 35.0 ng x h/ml for Day 1 and 3.0 ng/ml and 39.8 ng x h/ml for Day 90, respectively. Similarly, Cmax and AUC0-24 mean values for total equilin were 1.4 ng/ml and 17.4 ng x h/ml after Day 1 and 1.5 ng/ml and 17.3 ng x h/ml after Day 90, respectively. The mean tmax value for total estrone was 8.3 hours on Day 1 and 8.6 hours on Day 90, indicating a slower rate of absorption. The average estimate for observed drug accumulation index for the 24-hour dosing interval was calculated to be 1.1 for total estrone and 1.0 for total equilin. These data, taken together, indicate a slow and steady rate of absorption, minimal drug accumulation at steady state, and consistent drug exposure between Cenestin doses.

Perimenopausal women in estrogen vasomotor trials: contribution to placebo effect and efficacy outcome.

OBJECTIVE: To determine the difference, if any, in the placebo response when both perimenopausal and postmenopausal women are enrolled, compared with postmenopausal women alone, in a study assessing the efficacy of synthetic conjugated estrogen tablets on moderate-to-severe vasomotor symptoms (MSVS). METHODS: A total of 120 healthy women (72 active; 48 placebo) complaining of moderate-to-severe vasomotor symptoms were enrolled in a randomized, placebo-controlled, double-blind, multicenter clinical trial. In all, 109 patients completed treatment to week 12. Women were enrolled using minimal inclusion and exclusion criteria, and included perimenopausal women (n = 34; 0 to 6 months since last menses) as well as menopausal women (n = 79; > 12 months since last menses). RESULTS: Changes in MSVS in the intent-to-treat (ITT) population showed differences between the active and placebo treatments at weeks 4 (p < 0.022), 8 (p < 0.010) and 12 (p < 0.010). At week 12, the mean percentage reduction in MSVS was 81% for the active treatment group and 58% in the placebo treatment group. To examine the placebo response, the ITT population was broken down into groups defined by the time since their last menses. The perimenopausal group (0 to 6 months since last menses) demonstrated a consistently higher placebo response than that of the postmenopausal groups (> 12 months since last menses). CONCLUSIONS: Perimenopausal women contributed to a higher placebo response, compared with the rate of response previously reported in clinical studies of estrogen replacement in postmenopausal women. Including perimenopausal women in future vasomotor symptom trials will require study populations of sufficient size to maintain the statistical power to demonstrate a difference between therapeutic response to active or placebo treatment.

A 12-week clinical trial determining the efficacy of synthetic conjugated estrogens, A (SCE), in the treatment of vasomotor symptoms in menopausal women.

OBJECTIVE: To compare the clinical effects of a new oral synthetic conjugated estrogens, A (SCE), versus placebo in a clinically relevant population on the reduction in the mean number of moderate to severe vasomotor symptoms. DESIGN: A total of 120 healthy pre- and postmenopausal women (72 active, 48 placebo) were enrolled into a randomized, placebo-controlled, double-blind, multi-center clinical trial. Women of all races were enrolled, using minimal inclusion and exclusion criteria. Each subject received either orally administered SCE, in doses of 0.3 mg, 0.625 mg or 1.25 mg per day, or placebo. Analysis of variance was performed on the primary efficacy variable (change from baseline to weeks 4, 8, and 12 in the mean number of moderate to severe vasomotor symptoms). RESULTS: Changes in moderate to severe vasomotor symptoms in the intent to treat population showed statistically significant differences between the active and placebo treatments at week 4 (P < .022), week 8 (P < .010), and week 12 (P < .010). By week 12, the mean percentage reduction in moderate to severe vasomotor symptoms was 81%, from an average baseline of 96.8, to 16.5 hot flashes per week for the active treatment group. The overall incidence of expected estrogen-related adverse effects was modest. Laboratory tests and vital sign measurements did not reveal clinically significant changes or abnormalities from screening to the final visit in either treatment group. CONCLUSIONS: The results of this study confirm the efficacy and safety of SCE in the treatment of moderate to severe vasomotor symptoms in menopausal women. In addition, the study also demonstrated that the use of more liberal entry criteria did not materially affect the efficacy outcome.