# Treatment of Disturbed Sleep in Progressive Supranuclear Palsy: a randomized, remote, double-blinded, 6-week cross-over design study protocol comparing zolpidem, suvorexant, and placebo

## TL;DR

This study tests whether suvorexant or zolpidem improves sleep in people with progressive supranuclear palsy compared to a placebo.

## Contribution

The study introduces a remote, double-blind, cross-over trial design to evaluate orexinergic and GABAergic treatments for PSP-related sleep issues.

## Key findings

- PSP patients show disrupted sleep due to degeneration of sleep-regulating brain regions.
- Orexinergic neurons in the hypothalamus are relatively preserved in PSP, suggesting a potential treatment target.
- A remote trial design is proposed to reduce participant burden and improve accessibility for rare disease research.

## Abstract

Prior research identified profound sleep disruption in progressive supranuclear palsy (PSP). The hypothalamus and brainstem, areas that help regulate sleep/wake patterns, are among the earliest affected brain regions in PSP disease progression. Comparing polysomnography and quantitative-neuropathology metrics, we identified relative sparing of wake-promoting nuclei in PSP compared to Alzheimer’s disease, though PSP had more disrupted sleep. It led to the hypothesis that PSP patients have hyperinsomnia (or hyposomnia, little sleep) due to degeneration of sleep nuclei with a preservation of sleep neurons, causing a system unbalance. A higher neuronal count of wake-promoting nuclei was associated with greater nocturnal wake, regardless of disease. Specifically, orexinergic wake-promoting neurons in the lateral hypothalamus, previously described as the sleep-on/off switch, are relatively spared in PSP. Thus, we hypothesized that an orexinergic antagonist may be more effective in treating sleep/wake issues in PSP than other hypnotic medications. This study protocol was established to test the safety and efficacy of an orexinergic antagonist (suvorexant) targeting the wake-promoting system and contrasts it with a GABAergic receptor agonist (zolpidem) targeting sleep-promoting systems and placebo.

This is a remote clinical trial, designed as a double-blind, cross-over, within-subject 6-week trial, with 3 one-week-long conditions, separated by 1-week washout periods. The order of the 3 regimens is randomized and counterbalanced: placebo (microcrystalline cellulose), 15 mg/day suvorexant, 5 mg/day zolpidem. Participants are recruited from doctor and study referrals, registries, and support groups. Once onboarded, the trial coordinator maintains communication with the participant/caregiver throughout the 6 weeks. Assessments include neurological interviews, cognitive testing, and subjective questionnaire packets. Sleep and circadian rhythms are assessed through ambulatory EEG and actigraphy monitoring devices worn by the participant throughout the trial.

The study design aims to reduce participant and caregiver burden, while improving accessibility to such a study. Administering a remote clinical trial for a rare disease, however, creates unique issues that would otherwise be absent from in-person studies. Particularly, a symptom rather than disease-modifying trial is challenging to recruit for when potential disease-modifying therapeutics are available. Needing to coordinate with non-associated medical offices to attain medical records or prescriptions can cause frustrations for the potential participant, medical office, and study team. In recruitment, onboarding, and trial maintenance, this study design relies on consistent communication to support participant enrollment and satisfaction.

Treatment of Disturbed Sleep in Progressive Supranuclear Palsy (PSP); NCT04014389. Registered on June 2, 2019.