title: Power calculations and placebo effect for future clinical trials in progressive supranuclear palsy.
abstract: 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.
  
  
  
  We provide sample size calculations based on data collected in 187 PSP patients assigned to placebo in these trials. A placebo effect was calculated.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Department of Neurology, Philipps University, Marburg, Germany.|Second Department of Neurology, Attikon University Hospital, University of Athens, Athens, Greece.|Movement Disorders Department, Hygeia Hospital, Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Stamelou
authors.affiliation: Institute for Medical Biometry, Epidemiology and Medical Informatics, Saarland University, Campus Homburg, Homburg, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Schöpe
authors.affiliation: Institute for Medical Biometry, Epidemiology and Medical Informatics, Saarland University, Campus Homburg, Homburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Wagenpfeil
authors.affiliation: Medical Department, Noscira SA, Madrid, Spain.|Alzheimer Project Research Unit, Fundación CIEN, Madrid, Spain.
authors.forename: Teodoro
authors.initials: T
authors.lastname: Del Ser
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA.
authors.forename: Jee
authors.initials: J
authors.lastname: Bang
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA.
authors.forename: Iryna Y
authors.initials: IY
authors.lastname: Lobach
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA.
authors.forename: Phi
authors.initials: P
authors.lastname: Luong
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA.
authors.forename: Gesine
authors.initials: G
authors.lastname: Respondek
authors.affiliation: Department of Neurology, Philipps University, Marburg, Germany.
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Oertel
authors.affiliation: Memory and Aging Center, Department of Neurology, University of California, San Francisco, California, USA.
authors.forename: AdamL
authors.initials: A
authors.lastname: Boxer
authors.affiliation: Department of Neurology, Philipps University, Marburg, Germany.|Department of Neurology, Technische Universität München, Munich, Germany.|German Center for Neurodegenerative Diseases (DZNE), Munich, Germany.
authors.forename: Günter U
authors.initials: GU
authors.lastname: Höglinger
mesh_terms: D000203:Activities of Daily Living; D006801:Humans; D009842:Oligopeptides / Q000494:pharmacology; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D015990:Placebo Effect; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D012107:Research Design / Q000706:statistics & numerical data*; D018401:Sample Size; D012720:Severity of Illness Index; D013494:Supranuclear Palsy, Progressive / Q000188:drug therapy*; D013830:Thiadiazoles / Q000494:pharmacology
chemical_list: D009842:Oligopeptides; D013830:Thiadiazoles; C425904:davunetide; C520571:tideglusib
keywords: clinical trials; placebo effect; power calculation; progressive supranuclear palsy; rate of progression