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Updated: Mar 24, 2026
Author Spotlight: Methodologies and Advancements of Chronic Pain Management Research
Published on: January 5, 2024
Power calculations and placebo effect for future clinical trials in progressive supranuclear palsy
Maria Stamelou1,2,3, Jakob Schöpe4, Stefan Wagenpfeil4
1Department of Neurology, Philipps University, Marburg, Germany.
Background:
Two recent randomized, placebo-controlled trials of putative disease-modifying agents (davunetide, tideglusib) in progressive supranuclear palsy (PSP) failed to show efficacy, but generated data relevant for future trials.
Methods:
We provide sample size calculations based on data collected in 187 PSP patients assigned to placebo in these trials. A placebo effect was calculated.
Results:
The total PSP-Rating Scale required the least number of patients per group (N = 51) to detect a 50% change in the 1-year progression and 39 when including patients with ≤ 5 years disease duration. The Schwab and England Activities of Daily Living required 70 patients per group and was highly correlated with the PSP-Rating Scale. A placebo effect was not detected in these scales.
Conclusions:
We propose the 1-year PSP-Rating Scale score change as the single primary readout in clinical neuroprotective or disease-modifying trials. The Schwab and England Activities of Daily Living could be used as a secondary outcome. © 2016 International Parkinson and Movement Disorder Society.
