Fewer, less severe vasomotor symptoms reported by postmenopausal women using estetrol
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The estrogen estetrol was associated with decreased frequency and severity of vasomotor symptoms for postmenopausal women, study findings presented at the NAMS Annual Meeting showed.
Estetrol has previously been approved for use in combination with drospirenone as an oral contraceptive (Nextstellis, Mayne Pharma), but it would be “the first natural/native estrogen to be added to older women’s health in almost 80 years,” Wulf H. Utian, MBBCh, PhD, DSc(Med), FRCOG, FACOG, FICS, the Arthur Bill Professor Emeritus of reproductive biology at Case Western Reserve University in Cleveland, and the founder of the International Menopause Society, told Healio.
Utian and colleagues conducted E4Comfort I and II — two phase 3, randomized, double-blind trials of estetrol — among postmenopausal women aged 40 to 65 years who reported at least seven daily or at least 50 total moderate to severe vasomotor symptoms (VMS) in the week before the trial. Women were categorized by hysterectomy status and randomly assigned 1:1:1 to 15 mg estetrol, 20 mg estetrol or placebo daily for 12 weeks. The researchers assessed mean change in VMS severity and frequency at 4 weeks and 12 weeks.
The researchers assessed the general and endometrial safety of both dosages of estetrol through 12 months, as well as the safety of the combination of 20 mg estetrol and 100 mg progesterone among women who had not had a hysterectomy.
All endpoints were met in both studies, with estetrol significantly reducing VMS frequency and severity — up to 80% and 56%, respectively — at 4 weeks and 12 weeks compared with placebo, according to the researchers. Estetrol also was associated with improved quality of life measures, such as mood swings, anxiety, libido and joint pain, at 12 weeks.
According to Utian, the mode of action was surprising, as estetrol has different binding properties than the other naturally occurring estrogens — estrone, estradiol and estriol — “making it potentially safer in its overall risk-benefit [profile].”
Pending long-term safety and efficacy data, which are being analyzed in an ongoing study, the researhers said, estetrol will provide a new option for postmenopausal women experiencing VMS.