Endometrial effects of three doses of trimegestone, a new orally active progestogen, on the postmenopausal endometrium

Single-dose pharmacokinetics and pharmacodynamics assessment of oestriol and trimegestone containing vaginal rings in healthy women with childbearing potential

PURPOSE

To evaluate the pharmacokinetics and pharmacodynamics of oestriol (E3) and trimegestone (TMG) in healthy women after application of three different vaginal rings over 21 days. The vaginal rings had a nominal delivery rate of 0.413/0.050 mg/day (Test 1), 0.311/0.090 mg/day (Test 2) and 0.209/0.137 mg/day (Test 3) E3/TMG.

METHODS

Thirty-five healthy women were randomised to receive a single application of Test 1, 2 or 3 (Clinical Trial NCT03343912). The E3 and TMG plasma concentration was determined by LC-MS/MS. Oestradiol (E2) and progesterone (PG) serum concentrations, and bleeding patern were determined as pharmacodynamic parameters. Safety was assessed by evaluation of adverse events and local tolerability.

RESULTS

The total and maximum exposure of E3 and TMG increased in a proportional ratio to dose. However, not in a magnitude which was expected from the dose differences for E3. During Test 2 and 3 treatment all E2 and PG values remained on a well suppressed level until end of treatment. E2 and PG serum levels increased distinctly earlier after ring removal with Test 1 compared to Test 2 and 3. Test 3 achieved 95.24% of "no bleeding" days under treatment followed by Test 1 (91.67%), and Test 2 (86.15%).

CONCLUSIONS

The Test 3 formulation presented the best dose combination of E3/TMG for contraception. Moreover, all vaginal rings were well tolerated.

Bleeding profile and endometrial safety of continuous combined regimens 1 mg 17beta-estradiol/trimegestone versus 1 or 2 mg 17beta-estradiol/norethisterone acetate in postmenopausal women

OBJECTIVE

To compare the bleeding profile and endometrial safety of continuous combined 1 mg 17beta-estradiol (17beta-E2) and 0.125 mg trimegestone (TMG) with those of two continuous combined 17beta-E2 and norethisterone acetate (NETA) regimens.

STUDY DESIGN

This was a double-blind, randomized, multicenter study conducted in 12 European countries and Israel over a 2-year period. Healthy postmenopausal women with an intact uterus were given either 1 mg 17beta-E2/0.125 mg TMG, 2 mg 17beta-E2/1 mg NETA or 1 mg 17beta-E2/0.5 mg NETA for up to 26 cycles, each of 28 days.

RESULTS

The percentage of amenorrheic women was greater in most cycles up to cycle 13 in the 1 mg 17beta-E2/0.125 mg TMG group than in the comparator groups. The mean number of bleeding days was similar in the 1 mg 17beta-E2/0.125 mg TMG and the 1 mg 17beta-E2/0.5 mg NETA groups, but greater in the 2 mg 17beta-E2/1 mg NETA group. No endometrial hyperplasia was observed for any group.

CONCLUSION

Continuous combined 1 mg 17beta-E2/0.125 mg TMG exhibits a more favorable bleeding profile than 1 mg 17beta-E2/0.5 mg NETA up to 1 year, while providing an adequate protective effect on the endometrium.