Power calculations and placebo effect for future clinical trials in progressive supranuclear palsy

Academic Article


  • 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.
  • Authors

    Published In

  • Movement Disorders  Journal
  • Digital Object Identifier (doi)

    Author List

  • Stamelou M; Schöpe J; Wagenpfeil S; Del Ser T; Bang J; Lobach IY; Luong P; Respondek G; Oertel WH; Boxer A
  • Start Page

  • 742
  • End Page

  • 747
  • Volume

  • 31
  • Issue

  • 5