Updated May 2026 · ClinicalTrials.gov
GnRH Therapy on Cognition in Down Syndrome
Effect of Pulsatile GnRH Therapy on Cognition in Down Syndrome: Randomized Placebo Control Study
GnRH Therapy on Cognition in Down Syndrome (NCT04390646) is a Phase 2 / Phase 3 interventional studying Down Syndrome and Cognitive Decline, sponsored by Nelly Pitteloud. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.
About This Trial
Down syndrome (DS) is the most common chromosomal disorder; with the increasing life expectancy, about 80% of DS adults reach age 65 years old. Early Alzheimer's disease (AD) is the most common cause of death within this population. DS individuals already show AD neuropathology by the age of 30, while it becomes clinically recognized in their late forties. DS subjects also exhibit olfaction defects in adulthood. To date, there is no treatment available for the cognitive or olfactory defects in DS. The development of an effective treatment targeting cognitive dysfunction in DS adolescents/adults would be warranted. GnRH, a decapeptide secreted by hypothalamic neurons is the pilot light of reproduction in all mammals. Pulsatile GnRH acts on the gonadotrophs via the GnRH receptor (GNRHR) in the pituitary gland to stimulate LH and FSH, which themselves will act on the gonads to produce gametes and steroids. However, GNRHR are also expressed in cerebral cortex, hippocampus, amygdala, habenula, olfactory structures, and adrenal gland, suggesting that GnRH may have a role beyond reproduction. Recently, GnRH has been shown to be involved in the process of ageing and lifespan control. Notably, in murine models, GnRH acts as an anti-ageing factor, independent of sex hormones. While ageing is characterized by hypothalamic inflammation and diminished neurogenesis, particularly in the hypothalamus and the hippocampus, GnRH was able to promote adult neurogenesis. The regulation of GnRH secretion is complex and involves hormonal, neuronal input, and environmental factors. Prévot et al. recently explored cognition within the Ts65Dn model and showed an age-dependent loss of the ability to recognize new objects. Also, these mice exhibit defects in olfaction. Given the role of GnRH in anti-aging mice model, pulsatile GnRH or continuous GnRH infusion (leading to desensitization of the GNRHR) were given to the Ts65Dn mice for two weeks. Amazingly, pulsatile but not continuous GnRH therapy was able to recover cognitive and olfaction defects.
What Stage of Research Is This?
Phase 2 trials evaluate whether a treatment actually works against Down Syndrome and continue monitoring side effects. Phase 2 enrolls larger groups (typically 100–300 patients) and produces the first real efficacy signal. A successful Phase 2 readout is what unlocks the much larger Phase 3 confirmatory trials needed for FDA approval.
This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.
Target enrollment of 56 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Down Syndrome subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.
Who May Be Eligible (Plain English)
These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.
Original Eligibility Criteria
View original clinical language
Treatments Being Tested
GnRH, gonadorelin acetate
Drug administered by a subcutaneous pump
0.9% NaCl
Drug administered by a subcutaneous pump
Locations (1)
Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.
How to Talk to Your Doctor About This Trial
Bring the printable summary of this trial — including the NCT ID (NCT04390646), the sponsor (Nelly Pitteloud), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.
Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.
Authoritative Sources
The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.
Frequently Asked Questions
What is the NCT04390646 clinical trial studying?
Down syndrome (DS) is the most common chromosomal disorder; with the increasing life expectancy, about 80% of DS adults reach age 65 years old. Early Alzheimer's disease (AD) is the most common cause of death within this population. DS individuals already show AD neuropathology by the age of 30, while it becomes clinically recognized in their late forties. DS subjects also exhibit olfaction defects in adulthood. To date, there is no treatment available for the cognitive or olfactory defects in DS. The development of an effective treatment targeting cognitive dysfunction in DS adolescents/adul… The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.
Who can participate in NCT04390646?
Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.
How do I contact the trial site for NCT04390646?
Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.
Is participating in a clinical trial safe?
Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.
Where can I verify the data on this page?
Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.
How This Page Is Built
Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.
Source: ClinicalTrials.gov API v2 record for NCT04390646. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT04390646. Data: ClinicalTrials.gov."
Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.
Last updated 2026-05-08 · Data from ClinicalTrials.gov.