This document discusses interim analyses of clinical trial data. It describes different types of interim analyses including early stopping for safety or efficacy, sample size re-assessments, and administrative analyses. Early stopping for safety is generally done by a data monitoring committee to ensure participant safety. Early stopping for efficacy can determine whether a trial meets success criteria or shows futility. Sample size can be re-estimated based on nuisance parameters or treatment effects. Interim analyses are most useful when the alternative hypothesis is uncertain, enrollment is slow, or endpoints are acute. The document recommends doing some form of interim analysis or monitoring in almost all cases.

1. Interim Analysis of Clinical Trial Data:
Implementation and Practical Advice
Chris Pulling
Vice President
NAMSA

2. 2
Overview
 Types of interim analyses
 When are interim analyses appropriate?
 How are interim analysis plans implemented?
 When you should apply different approaches

3. 3
Types of Interim Analyses

4. 4
Early stopping for safety
 Generally, This is the purpose of a data
monitoring committee and data safety/monitoring
committee (DMC/DSMB)

5. 5
Early stopping for efficacy
 Success (alpha spending functions)
 Futility

6. 6
Sample size re-assessments
 Re-estimation based on nuisance parameters (simple,
almost worthwhile . . . usually free)
 Re-estimation based on treatment effect (rare,
controversial)

7. 7
Administrative
 Analyses with no impact on study design or
management

8. 8
Investor – Milestone-based financing
 Not necessarily early stopping for efficacy, futility or
safety
 No chance to commit a type I error
 Type II error??
*Type I and II errors described in the complete Remote Training Series

9. 9
When are Interim
Analyses Appropriate?

10. 10
It almost always makes sense to do
some form of interim analysis/monitoring
 Most useful when there is uncertainty with alternative
hypothesis
 More helpful if enrollment is slow and if endpoints are acute

11. 11
 To view the complete series about the Interim Analysis of
Clinical Trial Data: Implementation and Practical Advice
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