A Phase 4 interventional study of ganirelix acetate in Estrogen and Premenopause, sponsored by University of Delaware. Recruiting at 1 site in United States. Open to female participants aged 40 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-02.
Sponsored by University of Delaware · Phase 4, Interventional, and Basic science
The purpose of this study is to identify the impact of estradiol (E2) on the associations between (a) responsivity to daily stress or (b) sleep variability with vascular function in midlife premenopausal women.
In the last 20 years, deaths due to cardiovascular disease (CVD) have increased by up to 30% in midlife women. This increase in CVD risk in midlife women is at least partially explained by the declines in estradiol (E2) that occur across the menopausal transition. This loss of E2 induces vascular dysfunction, a major contributor to increased CVD risk. Nevertheless, we have shown that declines in vascular function are evident in some midlife premenopausal women, suggesting that vascular dysfunction-associated CVD risk cannot solely be explained by the loss of E2. Emerging factors that may help explain vascular dysfunction in midlife women include greater emotional vulnerability to daily stressors and poorer sleep health. However, not yet know is the extent to which daily stress and sleep health independently impact vascular function in midlife premenopausal women or the degree to which these associations are influenced by E2. The objective of this project is to test the central hypothesis that (a) greater negative affective responsivity to daily stressors and (b) greater sleep variability will each be related to more severe declines in vascular function in midlife premenopausal women and that these associations will be magnified during E2 suppression (simulated menopause) compared to the follicular phase of the menstrual cycle/placebo phase of hormonal contraception. We will assess affective responsitivy to daily stressors and device-measured sleep characteristics for 10 consecutive days and cutaneous microvascular endothelial function before and during pharmacological E2 suppression.
The investigators will assess multiple dynamic aspects of daily stress processes for 10 consecutive days (mobile app). Investigators will concurrently objectively assess sleep variability (ActiGraph wGT3X). Immediately before and after completion of these ambulatory assessments, Investigators will assess microvascular endothelial function using intradermal microdialysis coupled with laser Doppler flowmetry. Participants will complete two 10-day measurement bursts:The first will occur during the follicular phase of their menstrual cycle or the low hormone/placebo phase of hormonal contraception; The second will occur during supression of endogenous ovarian hormone production via GnRH antagonist ganirelix acetate.
University of Delaware is the lead sponsor of 128 studies on the registry; 22 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will undergo study measurements during the follicular phase of their natural menstrual cycle.
Participants will undergo study measurements during 10 days of daily ganirelix acetate (Antagon) injections.
Drug: ganirelix acetate
Ganirelix acetate (Antagon) will be used to prevent endogenous production of ovarian hormones in young women. Ganirelix is derived from native GnRH, and acts by competitively blocking GnRH receptors on the pituitary and subsequent pathways. Thus, administration of the GnRH antagonist (GnRHant) suppresses steroidogenesis, leading to low or undetectable serum estrogen and progesterone concentrations, which occurs within two days of initiation of administration. Women will self-administer subcutaneous injections (0.25 mg/day in 0.5 ml of normal saline) of the GnRH antagonist ganirelix acetate (Antagon, Organon, Inc., West Orange, New Jersey,) every day for \~12-15 days (starting on day \~2-4 of the menstrual cycle). Testing will occur on day 3-4 and day14-15 of using Antagon.
Also known as: Antagon
Endothelium-dependent dilation (EDD)
EDD will be calculated as the area under the dose-response curve (AUC) to ascending concentrations of acetylcholine.
Time frame: Immediately before and after each 10-day measurement burst
Negative affective response to daily stressors
Within-person composite slope between daily stressors and daily negative affect
Time frame: 10-day measurement burst
Sleep variability
Sleep onset standard deviation (minutes) estimated via actigraphy
Time frame: 10-day measurement burst
Plan to share: No
No publications or documents are linked to this record.
Started Nov 2024 (actual). Primary completion is estimated for Oct 2026, 23 months after the start.
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Studies of the drug tested here: Ganirelix