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

ABSTRACT: 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.

SUBMITTER: Stamelou M

PROVIDER: S-EPMC5289149 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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

Stamelou Maria M Schöpe Jakob J Wagenpfeil Stefan S Del Ser Teodoro T Bang Jee J Lobach Iryna Y IY Luong Phi P Respondek Gesine G Oertel Wolfgang H WH Boxer AdamL A Höglinger Günter U GU

Movement disorders : official journal of the Movement Disorder Society 20160307 5

<h4>Background</h4>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.<h4>Methods</h4>We provide sample size calculations based on data collected in 187 PSP patients assigned to placebo in these trials. A placebo effect was calculated.<h4>Results</h4>The total PSP-Rating Scale required the least number of patients per group (N ...[more]

PMID: 26948290

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Project description:Progressive supranuclear palsy causes diverse clinical presentations, including classical Richardson's syndrome and several variant phenotypes. Clinical trials of disease-modifying therapies have recently been completed, with more planned for the next 2 years. However, many people with progressive supranuclear palsy do not meet eligibility criteria for these clinical trials. Understanding clinical progression with different phenotypes would improve trial design and enhance the accuracy of risk-benefit and cost-benefit assessments of new treatments for progressive supranuclear palsy. We set out to determine rates of motor and cognitive progression of possible, probable and definite progressive supranuclear palsy, with different phenotypes, from a representative cohort in a regional UK healthcare service. Longitudinal clinical data from people with Richardson's syndrome and variant phenotypes were analysed using linear mixed-modelling, using both the full and modified versions of the Progressive Supranuclear Palsy Rating Scale, Mini-Mental State Examination and the revised Addenbrooke's Cognitive Examination. Subgroup analyses considered patients meeting recent Phase II trial entry criteria and patients with neuropathological confirmation. Two hundred and twenty-seven patients [male = 59%, mean age (±standard deviation), 71.8 (±7.0) years] were followed for a mean 21.6 (±15.6) months. One hundred and seventy-four (77%) had Richardson's syndrome at the outset, 25 had cortical variant presentations (13%, frontal, corticobasal, speech and language variants) and 28 had subcortical variant presentations (14%, parkinsonism, postural instability and gait freezing variants). Across all participants, annual progression in Richardson's syndrome was faster than variant phenotypes on the Mini-Mental State Examination (-1.8 versus -0.9/year, P = 0.005) and revised Addenbrooke's Cognitive Examination (-5.3 versus -3.0/year, P = 0.01) but not the Progressive Supranuclear Palsy Rating Scale (9.0 versus 7.1/year, P = 0.2) nor the modified Progressive Supranuclear Palsy Rating Scale (2.7 versus 2.3/year, P = 0.4). However, for those with more than 1 years' follow-up, a significant difference was observed between Richardson's syndrome and variant phenotypes in Progressive Supranuclear Palsy Rating Scale (8.7 versus 6.3/year, P = 0.04). Survival was longer in variant phenotypes than Richardson's syndrome [7.3 (±3.9) versus 5.6 (±2.0) years, P = 0.02]. Pathologically confirmed cases (n = 49) supported these findings. Patients meeting basic trial-eligibility criteria (n = 129) progressed faster on the Progressive Supranuclear Palsy Rating Scale than trial-not-eligible patients (10.1 versus 6.1/year, P = 0.001). In conclusion, phenotypes other than Richardson's syndrome show slower progression and longer survival. Trial criteria do not select representative progressive supranuclear palsy cases. This has implications for trial design, and application of trial results to clinically more diverse patient populations.

Project description:BackgroundThe Movement Disorder Society diagnostic criteria for progressive supranuclear palsy introduced the diagnostic certainty level "suggestive of progressive supranuclear palsy" for clinical conditions with subtle signs, suggestive of the disease. This category aims at the early identification of patients, in whom the diagnosis may be confirmed as the disease evolves.ObjectiveTo assess the diagnostic performance of the defined clinical conditions suggestive of progressive supranuclear palsy in an autopsy-confirmed cohort.MethodsDiagnostic performance of the criteria was analyzed based on retrospective clinical data of 204 autopsy-confirmed patients with progressive supranuclear palsy and 216 patients with other neurological diseases.ResultsThe conditions suggestive of progressive supranuclear palsy strongly increased the sensitivity compared to the National Institute of Neurological Disorders and Stroke and Society for Progressive Supranuclear Palsy criteria. Within the first year after symptom onset, 40% of patients with definite progressive supranuclear palsy fulfilled criteria for suggestive of progressive supranuclear palsy. Two-thirds of patients suggestive of progressive supranuclear palsy evolved into probable progressive supranuclear palsy after an average of 3.6 years. Application of the criteria for suggestive of progressive supranuclear palsy reduced the average time to diagnosis from 3.8 to 2.2 years.ConclusionsClinical conditions suggestive of progressive supranuclear palsy allow earlier identification of patients likely to evolve into clinically possible or probable progressive supranuclear and to have underlying progressive supranuclear palsy pathology. Further work needs to establish the specificity and positive predictive value of this category in real-life clinical settings, and to develop specific biomarkers that enhance their diagnostic accuracy in early disease stages. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

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

Publications

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

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