The GnRH Therapy on Cognition in Down Syndrome study (ClinicalTrials.gov identifier: NCT04390646) is an ongoing Phase 2/3 randomized, double-blind, placebo-controlled clinical trial investigating the effects of pulsatile gonadotropin-releasing hormone (GnRH) therapy on cognitive function in adults with Down Syndrome[1]. The study is conducted at the Centre Hospitalier Universitaire Vaudois (CHUV) in Lausanne, Switzerland, under the leadership of Professor Nelly Pitteloud.
Down Syndrome is the most common chromosomal disorder, affecting approximately 1 in 700 births. With increasing life expectancy, approximately 80% of individuals with Down Syndrome now reach age 65 years[1:1]. This population faces a dramatically elevated risk of early-onset Alzheimer's disease, with neuropathology typically appearing by age 30 and clinical symptoms emerging in the late forties[1:2]. Currently, no effective treatments exist for the cognitive or olfactory deficits in Down Syndrome.
GnRH is a decapeptide hormone secreted by hypothalamic neurons that serves as the primary regulator of the reproductive axis. However, GnRH receptors (GNRHR) are also expressed in brain regions beyond the pituitary, including the cerebral cortex, hippocampus, amygdala, habenula, olfactory structures, and adrenal gland[1:3]. This widespread expression suggests that GnRH may have functions extending beyond reproduction.
Recent research has demonstrated that GnRH plays a role in ageing and lifespan control. In murine models, GnRH has been shown to function as an anti-ageing factor independent of sex hormones. Ageing is characterized by hypothalamic inflammation and diminished neurogenesis, particularly in the hypothalamus and hippocampus. Notably, GnRH treatment was able to promote adult neurogenesis in these models[1:4].
Research by Prévot et al. explored cognition in the Ts65Dn mouse model of Down Syndrome, demonstrating an age-dependent loss of object recognition ability along with olfactory defects. When pulsatile GnRH therapy (but not continuous GnRH infusion) was administered for two weeks, both cognitive and olfactory defects were recovered[2]. This preclinical evidence provided the foundation for the current clinical trial.
The study employs a multicentric randomized double-blind design with triple masking (participant, care provider, and investigator are all blinded)[1:5].
Key design parameters:
The trial aims to enroll approximately 56 participants with the following conditions:
| Arm | Type | Intervention |
|---|---|---|
| Pulsatile GnRH pump treatment | Active Comparator | GnRH (gonadorelin acetate) administered via subcutaneous pump |
| Pulsatile placebo pump treatment | Placebo Comparator | 0.9% NaCl (saline) administered via subcutaneous pump |
The drug (Lutrelef, gonadorelin acetate) is delivered using a pulsatile pump system to mimic the natural physiological secretion pattern of GnRH[1:7].
| Measure | Time Frame |
|---|---|
| Cognition | Baseline to end of treatment (Week 24) |
Cognitive Assessments:
Quality of Life:
Metabolic Markers:
| Parameter | Value |
|---|---|
| Status | Recruiting |
| Start Date | August 27, 2020 |
| Primary Completion Date | December 2028 (estimated) |
| Completion Date | December 2028 (estimated) |
| Last Updated | February 9, 2024 |
Lead Sponsor/Principal Investigator:
Location:
This trial represents a novel therapeutic approach targeting a population with extremely high unmet medical needs. Individuals with Down Syndrome face near-universal development of Alzheimer's disease neuropathology by age 30, yet no approved treatments exist for their cognitive decline. The repurposing of GnRH—already approved for reproductive disorders—for cognitive enhancement in Down Syndrome could provide a transformative therapy if efficacy is demonstrated.
The trial also explores the relationship between GnRH and olfactory function, as smell deficits often precede cognitive decline in both Down Syndrome and Alzheimer's disease. If successful, this approach could potentially be extended to sporadic AD and other forms of cognitive decline associated with ageing.