Novel Combined Oral Contraceptive Effective in Phase 3 Trial

Previous Phase 2 studies confirmed esterol has minimal impact on liver cells and metabolic pathways, as well as on coagulation parameters.

Mithra announced that the Phase 3 Estelle study met its primary efficacy endpoint, demonstrating “excellent contraceptive efficacy” in line with similar approved combined hormonal contraceptives

Estelle, a combined oral contraceptive, includes estetrol 15mg and drospirenone 3mg. Estetrol is a native estrogen with selective action in tissues. Previous Phase 2 studies confirmed estetrol has minimal impact on liver cells and metabolic pathways, as well as on coagulation parameters. The hemostasis study showed that overall, Estelle was associated with a lower increase in coagulation factors and a lower decrease in coagulation inhibitors vs the comparators.

The Phase 3 study evaluated the safety, acceptability, efficacy, and cycle control of Estelle in healthy women aged 16 to 50 years for a 12-month duration (thirteen 28-day cycles). The primary endpoint was contraceptive efficacy as measured by the number of on-treatment pregnancies per 100 women per 12 months of exposure among the 16 to 35-year-old subjects at study entry. 

Results showed a Pearl Index (PI) of 2.41 per 100 women (95% CI, 1.73-3.88) during 13,979 cycles among women 16-35 years of age. Overall, for women 16-50 years old, the PI was 2.30 (95% CI, 1.67-3.64) during 15,797 cycles.

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“This novel product has great potential based on Phase 2 data which shows less effects on liver metabolism, lipids, and the coagulation profile as compared to contraceptives using ethinyl estradiol,” said Mitchell Creinin, Director of Family Planning at the University of California, Davis. “The overall efficacy, safety and excellent cycle control demonstrated in the Phase 3 studies confirms that Estelle offers a truly innovative, next-generation oral contraceptive option.”

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This article originally appeared on MPR