Recruiting

NCT Number: NCT07235917

A Study to Investigate Mibavademab in Adult Women With Functional Hypothalamic Amenorrhea

This study is researching an experimental drug called mibavademab (also called "study drug"). The study is focused on patients with a condition called Functional Hypothalamic Amenorrhea (FHA). FHA is a condition where a woman stops menstruating because the brain is not sending the correct hormonal signals to the ovaries, which then are not able to cycle and ovulate properly.

The aim of the study is to see how well the study drug helps the body make the hormones necessary for ovulation and reproduction, and to assess its safety.

The study is looking at several other research questions, including:

* Whether the drug helps bone health * What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the body makes antibodies against the study drug (which could make the drug less effective or could lead to side effects)

Recruiting

Interested in participating?

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Key information

Conditions

Functional Hypothalamic Amenorrhea (FHA)

Age range

18 year–40 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 2

Primary location

Arensia Exploratory Medicine Clinic, Phoenix, Arizona, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

Diagnosis of FHA after exclusion of anatomic or organic causes of amenorrhea
Has had no menstrual bleeding episode within 3 months (or longer) prior to day 1, as described in the protocol
Has a Body Mass Index (BMI) ≥18.5 and <25 kg/m^2 at screening, or BMI ≥25 to <30 kg/m^2 at screening AND percentage of body fat <20% from rigorous exercise as determined by the investigator through Standard of Care (SoC) methods (eg, skinfold thickness, DXA, bioimpedance) within 6 months of screening, as described in the protocol

Key Exclusion Criteria:

Has presence of primary amenorrhea (failure to reach menarche, first menstrual cycle)
Has blood estradiol ≥50 pg/mL or blood progesterone ≥1 ng/mL at screening
Has uterine (eg, absence of uterus, prior endometrial ablation, endometriosis, outflow tract disorders) or ovarian (eg, absence of an ovary, presence of polycystic ovaries) conditions that impact assessment of menses or of the HPO axis
Has conditions other than FHA that may cause amenorrhea or menstrual cycle disturbances (eg, polycystic ovarian syndrome, hyperprolactinemia, primary ovarian insufficiency, untreated primary hypothyroidism, primary hyperthyroidism)
Polycystic ovarian morphology with an ovarian volume >10 cc on TransVaginal UltraSound (TVUS) [or TransAbdominal Pelvic Ultrasound (TAPU) if applicable] at baseline
Presence of follicle ≥17 mm, evidence of ruptured follicle, and/or evidence of corpus luteum on TVUS (or TAPU if applicable) at baseline

NOTE: Other protocol-defined Inclusion/Exclusion criteria apply

Treatment and study plan

Mibavademab

Drug

Administered per the protocol

Other names: REGN4461

Placebo

Other

Administered per the protocol

Primary outcomes

Change from the highest serum estradiol observed during a 28-day period

Time frame: Baseline to month 6

Secondary outcomes

Change from the mean serum estradiol observed during a 28-day period

Time frame: Baseline to month 6
Occurrence of menses followed by mid-cycle serum estradiol ≥200 pg/ml and mid-luteal serum progesterone ≥7.9 ng/ml

Time frame: At month 6
Change in the highest serum estradiol

Time frame: Baseline through 6 months
Occurrence of serum estradiol ≥200 pg/ml

Time frame: Through 6 months
Number of ovulatory menstrual cycles

Time frame: Through 6 months
Number of menses with mid-luteal serum progesterone ≥7.9 ng/ml and midluteal estradiol ≥100 pg/ml

Time frame: Through 6 months
Number of menstrual cycles

Time frame: Through 6 months
Percent change in Bone Mineral Density (BMD) at the lumbar spine, as measured by Dual X-ray Absorptiometry (DXA)

Time frame: Baseline to 6 months
Absolute change in BMD at the lumbar spine, as measured by DXA

Time frame: Baseline to 6 months
Percent change in Bone Mineral Content (BMC) at the lumbar spine, as measured by DXA

Time frame: Baseline to 6 months
Absolute change in BMC at the lumbar spine, as measured by DXA

Time frame: Baseline to 6 months
Percent change in BMD at the lumbar spine, as measured by DXA in participants with baseline lumbar spine BMD Z-score <-1

Time frame: Baseline to 6 months
Absolute change in BMD at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Time frame: Baseline to 6 months
Percent change in BMC at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Time frame: Baseline to 6 months
Absolute change in BMC at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Time frame: Baseline to 6 months
Occurrence of Treatment Emergent of Adverse Events (TEAEs)

Time frame: Up to day 280
Severity of TEAEs

Time frame: Up to day 280
Concentrations of total mibavademab in serum

Time frame: Up to day 280
Occurrence of Anti-Drug Antibodies (ADA) to mibavademab

Time frame: Up to day 280
Magnitude of ADA to mibavademab

Time frame: Up to day 280

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Trials Administrator

CONTACT

[email protected]

844-734-6643

Sponsors and collaborators

Lead sponsor

Regeneron Pharmaceuticals

Industry

Registry information

Official study title

A Phase 2, Double-Blind, Placebo-Controlled Study to Investigate the Safety and Efficacy of Mibavademab in Adult Women With Functional Hypothalamic Amenorrhea

Acronym: KYRIAD

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Nov 19, 2025
Registry last updated: Jul 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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View Trial Details

Key information

Conditions

Age range

Sex eligibility

Study type

Phase

Primary location

Who can participate

Treatment and study plan

Mibavademab

Placebo

Primary outcomes

Change from the highest serum estradiol observed during a 28-day period

Secondary outcomes

Change from the mean serum estradiol observed during a 28-day period

Occurrence of menses followed by mid-cycle serum estradiol ≥200 pg/ml and mid-luteal serum progesterone ≥7.9 ng/ml

Change in the highest serum estradiol

Occurrence of serum estradiol ≥200 pg/ml

Number of ovulatory menstrual cycles

Number of menses with mid-luteal serum progesterone ≥7.9 ng/ml and midluteal estradiol ≥100 pg/ml

Number of menstrual cycles

Percent change in Bone Mineral Density (BMD) at the lumbar spine, as measured by Dual X-ray Absorptiometry (DXA)

Absolute change in BMD at the lumbar spine, as measured by DXA

Percent change in Bone Mineral Content (BMC) at the lumbar spine, as measured by DXA

Absolute change in BMC at the lumbar spine, as measured by DXA

Percent change in BMD at the lumbar spine, as measured by DXA in participants with baseline lumbar spine BMD Z-score <-1

Absolute change in BMD at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Percent change in BMC at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Absolute change in BMC at the lumbar spine, as measured by DXA, in participants with baseline lumbar spine BMD Z-score <-1

Occurrence of Treatment Emergent of Adverse Events (TEAEs)

Severity of TEAEs

Concentrations of total mibavademab in serum

Occurrence of Anti-Drug Antibodies (ADA) to mibavademab

Magnitude of ADA to mibavademab