What is it? Why is it important?

An Interim Analysis (IA) is a statistical evaluation of collected study data before the completion of the study. The aim is to assess whether the study can continue as planned.

 

The results of an IA may lead to a reassessment of the sample size (e.g. if the assumptions made during study planning do not align with the observed data) and/or to early study termination.

 

Early study termination may be due to::

  • Futility: there is a high probability that the intervention is ineffective or has only minimal benefit
  • Safety: there are unacceptable participant safety risks (e.g. with more adverse events in the intervention group compared to the control group, resulting in an unacceptable risk-benefit-ratio)
  • Efficacy: due to a significant beneficial treatment effect, the study success is declared early. Continuing the study without providing the intervention to all participants would be unethical (e.g. principles of ethics)

What do I need to do?

As a SP-INV, assess whether an interim analysis is needed to identify:

  • Risks to study quality (e.g. risks to the study’s critical quality factors)
  • Participant safety
  • Requirement for early study termination due to clear evidence of treatment efficacy or lack thereof

 

As a SP-INV:

  • Discuss the planned IA with a statistician, as IA results may affect the sample size calculation and overall study design
  • Describe the IA in the study protocol, and, if applicable, in the Statistical Analysis Plan (SAP). Include the type, timing, and frequency of IAs
  • Define the composition and requirement of the independent Data Safety Monitoring Board (DSMB), also named the Independent Data Monitoring Committee (IDMC). 

 

Note: Interim analyses are usually conducted by an independent statistician, with IA results provided to the DSMB / IDMC. Based on IA results, the committee can provide important impartial recommendations, thereby supporting the SP-INV on how to proceed with the study.

 

Where can I get help?

Your local Research Support Centre↧ can assist you with experienced staff regarding this topic

  • Basel, Departement Klinische Forschung (DKF), dkf.unibas.ch

  • Lugano, Clinical Trials Unit (CTU-EOC), ctueoc.ch

  • Bern, Department of Clinical Research (DCR), dcr.unibe.ch

  • Geneva, Clinical Research Center (CRC), crc.hug.ch

  • Lausanne, Clinical Research Center (CRC), chuv.ch

  • St. Gallen, Clinical Trials Unit (CTU), h-och.ch

  • Zürich, Clinical Trials Center (CTC), usz.ch

SCTO Research Tools & Resources

Video

References

ICH GCP E6 (R3) – see in particular

  • 2.6 Investigator: Premature termination or suspension of a trial
  • 3.10.1 Risk management
  • 3.17.1 Reports: The premature termination or suspnesion of a trial

ICH Topic E9 – see in particular

  • 4.1 Trial monitoring and interim analysis
  • 4.5 Interim analysis and early stopping
  • 7.2.1 Efficacy data
  • 7.2.2 Safety data
Abbreviations
  • ICH – International Council for Harmonisation
  • ICH GCP – International Council for Harmonisation Good Clinical Practice
  • DSMB - Data Safety Monitoring Board
  • IDMC – Independent Data Monitoring Committee
  • SAP -  Statistical Analysis Plan
  • SP-INV – Sponsor Investigator
Development ↦ Statistic Methodology ↦ Statistics in the Protocol ↦ Interim Analysis
Study
Basic

Provides some background knowledge and basic definitions

Basic Monitoring
Concept

Starts with a study idea

Ends after having assessed and evaluated study feasibility

Concept Statistic Methodology
Concept Drug or Device
Development

Starts with confidence that the study is feasible

Ends after having received ethics and regulatory approval

Development Drug or Device
Set-Up

Starts with ethics and regulatory approval

Ends after successful study initiation

Set-Up Ethics and Laws
Set-Up Statistic Methodology
Set-Up Quality and Risk
Set-Up Drug or Device
Conduct

Starts with participant recruitment

Ends after the last participant has completed the last study visit

Conduct Statistic Methodology
Conduct Drug or Device
Completion

Starts with last study visit completed

Ends after study publication and archiving

Completion Drug or Device
Current Path (click to copy): Development ↦ Statistic Methodology ↦ Statistics in the Protocol ↦ Interim Analysis