Table 1

Two estimand strategies for PD trials

AttributeTypical PD trial estimandAlternative treatment policy estimand
TreatmentExperimental treatment or placebo added to background therapy with adjustment of the background medication permitted during the first titration period, but not thereafterExperimental treatment or placebo added to background therapy, dosed as required, and alternative medication, dosed as required
PopulationIdiopathic PD with ‘wearing off’ phenomenonIdiopathic PD with ‘wearing off’ phenomenon
OutcomeChange from baseline in absolute OFF-time up to the end of maintenance phaseChange from baseline in absolute OFF-time up to the end of maintenance phase
Population-level summaryMean differenceMean difference
Postrandomisation eventAdjustment of PD medication during the maintenance period
Hypothetical strategy; that is, the treatment effect in the hypothetical case where adjustment to PD medication did not occur
Adjustment of PD medication during the maintenance period
Treatment policy strategy where data after the post randomisation events is collected and used in the analysis.
  • PD, Parkinson’s disease.