Choosing Appropriate Estimands in Clinical Trials

Area of Science:

• Clinical Trials
• Biostatistics
• Pharmaceutical Research

Background:

• Clinical trials frequently encounter protocol deviations and missing data, complicating the assessment of true treatment effects.
• Differentiating between ideal treatment effects (efficacy) and real-world outcomes (effectiveness) is crucial due to adherence variations.

Purpose of the Study:

• To highlight the importance of estimands in clinical trial planning.
• To provide guidance on selecting appropriate estimands, focusing on the distinction between efficacy and effectiveness.
• To present a comprehensive process chart for clinical trial planning, incorporating estimand definition.

Main Methods:

• The study reviews the concept of estimands and their role in addressing adherence and missing data.
• A process chart is proposed, outlining key planning steps from estimand selection to analysis.
• Examples from clinical practice are used to illustrate the application of different estimands.

Main Results:

• Defining the estimand is a critical prerequisite for designing clinical trials and conducting primary analyses.
• The choice of estimand significantly influences subsequent trial design, analysis strategies, and sensitivity analyses.
• The proposed process chart offers a structured approach to decision-making during trial planning.

Conclusions:

• Clear definition and justification of the primary estimand are essential for robust clinical trial protocols.
• The process chart aids in systematically addressing all planning aspects, particularly the efficacy versus effectiveness choice.
• Implementing these recommendations can improve the reliability and interpretability of clinical trial results.